Currently, the world’s longest commercial flight takes seventeen and a half hours. It connects Auckland, New Zealand to Doha, Qatar, and was only introduced in February. It probably won’t be long, though, before this record is usurped. Nineteen-hour flights from Singapore to New York and twenty-hour treks from Sydney to London are expected to join the fray soon.

These ultra long-haul flights are becoming more efficient and economically viable. They’re also a slog for passengers. But is there a point where a super-long flight becomes a public health risk?

There are a few health risks linked to flying (yes, aside from being dragged off the plane. Or stung by falling scorpions). Tacking on a few more hours probably won’t have much of an impact, though.

“If it’s one seventeenth of the trip, it’s not that big of a deal,” says Fanancy Anzalone, an aerospace medicine physician and past president of the Aerospace Medical Association. Still, he says, “There’s a multitude of things that you need to be concerned about when you do go on a long-haul flight.”

Sitting still in a cramped seat for hours isn’t just unpleasant—it can lead to deep vein thrombosis, when blood clots form in the legs because of poor blood flow. The longer you don’t move, the greater your risk. Worst case scenario, the clot can break free and lodge in the lungs. Fortunately, this is rare. And you can cut down on your risk by getting up and walking around or flexing your legs.

Passengers “really need to think about getting up anywhere between three to four hours and walk around,” Anzalone says. “But by sitting on your chair and just pumping your legs—in essence pressing down on your heels and up with your toes—that little bit can make a big difference in whether somebody is going to have a [deep vein thrombosis].”

It also helps to stay hydrated—which means avoiding the very drinks you’re most likely to reach for on a flight. Soft drinks, booze, and coffee are all diuretics, meaning that they make you pee more. “If you are going on a long haul it’s recommended that you start [hydrating] the day before,” Anzalone says.

The superdry air on a plane can make it easier to get dehydrated. It also dries out your mucus membranes, which keeps them from trapping germs. Which is unfortunate, because there is always chance you’ll catch a cold or worse from your fellow passengers. “As each hour goes by you have a little more exposure, and so therefore the probability of catching a cold on a flight like that grows,” Anzalone says.

So you might be out of luck if you’re seated next to someone who is already ill. However, the idea that the recirculating air on a plane abets disease transmission is a myth. “Airflow and circulation of cabin air is quite sophisticated technically, so there is usually no high risk of getting infected even if you have someone [sick] sitting two rows before,” says Jochen Hinkelbein, a professor of anesthesiology at the University of Cologne in Germany and president of the German Society of Aerospace Medicine .

You should be more concerned about the tray tables, bathrooms, and other germ-gathering surfaces you’re likely to come into contact with. They do get wiped down after flights. “The major airlines that are flying long-haul in my experience do extremely well in making sure that he airplane is as clean…as possible,” Anzalone says. But he does recommend traveling with hand wipes or sanitizer. Really, it’s best to touch as little as possible.

There’s not much you can do about the cosmic rays, though. Each time a passenger flies, they are exposed to a tiny amount of radiation from space. “The more time you’re on the plane, the more radiation exposure you’ll get,” says Steven Barrett, an aerospace engineer at MIT.

However, the radiation most travelers are exposed to in a given year falls comfortably within the recommended radiation exposure for a member of the public. “The very frequent travelers who are flying on long-haul flights could potentially go above the recommended limits of radiation exposure,” says Barrett, who has calculated how much radiation flyers are exposed to. “But that’s not within the region where you’d have any real health concerns.” It’s unclear how harmful these still-low levels of radiation exposure are, or if they are harmful at all, he says.

Pilots and other flight crewmembers do spend enough time in the air that the Centers for Disease Control and Prevention considers them radiation workers. The agency recommends they try to limit their time on flights that are very long, fly at high altitudes, or fly over the poles.

Another concern is that the air pressure is also lower on a plane than it is at sea level. This doesn’t bother most people. However, the thin air can cause problems for those who are old or have heart conditions or other pre-existing illnesses.

Ultimately, the longer a flight is, the more time you have for something to go wrong. And planes have become larger in recent years, which also increases the probability that someone on board will have a medical emergency.

“Traveling itself is becoming more and more popular, more and more convenient even for the old ones with…pre-existing diseases,” Hinkelbein says. “So we have an…unhappy triad which is the setting is not ideal for unhealthy persons, the persons are older and older and having more pre existing diseases, and not moving within the aircraft cabin, drinking only a little bit.”

There’s no specific amount of time that is unsafe, and it depends on the individual traveler. “But my feeling is below 12 [or] 14 hours, you can nearly send everyone, if it’s longer you should be a little careful,” Hinkelbein says.

About half of the medical issues that do crop up on planes are cardiovascular troubles such as fainting or dizziness. Estimates for how often people have in-flight medical emergencies vary, ranging from one passenger in 10,000 to one in 40,000.

For these crises, planes come equipped with medical kits and equipment such as defibrillators. “Every one of the long-haul flights have a way by radio to connect to physicians that are available around the world to talk to them,” Anzalone says. “I have talked to pilots about medical issues that are on board and how to handle it, do you divert or not divert.”

However, very few airlines have forms to document when passengers do get sick, Hinkelbein says. He’d like to see standardized forms and an international registry where all inflight medical problems are reported. “Then you can try to figure out what are really the most [frequent] causes of inflight medical problems.”

For the vast majority of people, though, even the longest flights will pass uneventfully. “The flying public on major airlines is very safe,” Anzalone says.

In fact, a plane’s most profound influence probably isn’t on the passengers—it turns out that airplanes cruising miles above the Earth’s surface can cause problems down below.

“The main health impact is probably emissions that come from them and the health impacts for people for the ground,” Barrett says. He and his colleagues have estimated that 16,000 people globally die each year because of air pollution caused by planes. These emissions, which are linked to lung cancer and cardiopulmonary disease, came from planes at cruising height as well as those in the midst of takeoff and landing.

But ultra long-haul flights may actually spew less harmful pollution than routes that include stopovers. “From a human health perspective the direct flight would be better,” Barrett says. “Even though the high-altitude emissions do affect human health on the ground, the low altitude emissions at airports when the airplanes take off and land and taxi are still more impactful because they’re closer to where people live.”

One of the more radical ideas to cut down on plane-related pollution is to use electric aircraft, which would release no emissions while flying. Unfortunately, however, the longest flights are unlikely to be good candidates for this technology.

“Electric aircraft might be possible for shorter ranges, maybe up to 1000 or so miles, but it looks much less likely that electric aircraft could contribute in a meaningful way for ultra long-haul flights,” Barrett says. “That’s where there’s no obvious or no real solution on the horizon.”

This post has been updated. It was originally published on April 18, 2017.

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This year, the Great Plains, Florida, and the Carolinas are expected to be the worst areas of the US for people with allergies, according to a report by the nonprofit Asthma and Allergy Foundation of America. Outside these regions, Scranton, Pennsylvania, made the list at No. 3, and Rochester, New York, at No. 20. But as anyone with allergies knows—you can suffer anywhere.

Fortunately, there are several kinds of allergy medications that can tame symptoms. But, it’s important to know the differences among the many options to find out when and how long you should take them. Allergy experts have a few tips to keep in mind while bracing for the start of allergy season. 

There are two main categories of antihistamines, says Eric Macy, an allergist-immunologist at Kaiser Permanente in San Diego. In addition to their allergy-fighting effects, “first-generation” antihistamines such as Benadryl can cause drowsiness and coordination problems. They belong to a class of drugs called anticholinergics whose long-term use may increase the risk of dementia.

[Related: Does taking allergy medication make my allergies worse?]

“The first-generation antihistamines have more cognitive or brain-related effects than the second generation do, so it’s not wise to take that every day,” says Sai R. Nimmagadda, an allergist-immunologist at Northwestern University Feinberg School of Medicine and Lurie Children’s Hospital of Chicago. 

Newer “second-generation” antihistamines including Claritin, Zyrtec, and Allegra are generally safe to use regularly. However, Nimmagadda says, some people find that a given antihistamine becomes less effective over time. Rather than increasing the dose, he recommends switching to a different antihistamine. “I tell my patients to alternate the antihistamine therapies every three to six months if they find they have become tolerant to a particular medication,” Nimmagadda says.

Start using nasal spray before the pollen onslaught

Antihistamines are very effective against sneezing, itchy eyes, runny noses, and hives, but they don’t help very much with congestion, Macy says. However, corticosteroid nasal sprays like Flonase treat stuffiness as well as other allergy symptoms. They contain lab-made versions of naturally occuring hormones that calm inflammation.

Corticosteroids can be used daily without losing their edge, Nimmagadda says. “The only thing is that with intranasal steroids it’s important to start them early in the season,” he says. 

If you wait until your immune system goes to work against that dreaded pollen and your symptoms flare up, corticosteroids won’t work as well. Nimmagadda likens it to fighting a blaze before it gets out of hand. “If you have a small fire, it’s easier to put out with a garden hose,” he says. “If you have a large fire, when you try to use a garden hose it’s not going to work very well.”

An even simpler remedy is to use saline (aka salt water) washes to flush mucus and debris from your nasal passages. These solutions can be purchased at the pharmacy or made at home—and using them will likely cut down on the amount of allergy medications you need to keep your symptoms in check, Nimmagadda says.

“The cheapest and best treatment you can do is to wash your nose of all the pollen allergens every morning and night,” he says. “One of the mainstays of my treatment regimens is the saline rinses.” 

[Related: How to tell seasonal allergies from COVID-19 symptoms]

Another thing to keep in mind, Macy says, is that if you’re experiencing congestion and sinus pressure without other symptoms like itching and sneezing, it’s probably not caused by allergies. Other treatable conditions including migraines, infections, and nasal polyps, may actually be to blame. 

Check in with your doctor

If you’re dealing with nasal symptoms year-round, Macy advises, it’s a good idea to visit a doctor and discuss more effective treatment options.

“Basically it comes down to: See an allergist, figure out what the cause of the problem is, and get it dealt with [rather] than taking antihistamines to paint over rust,” he says. 

Immunotherapy treatments—allergy shots and drops—decrease a person’s sensitivity to pollen, dust mites, and other irritants. They work by exposing the immune system to gradually increasing doses of the allergen and can provide long-term relief, Nimmagadda says. 

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Raul Puente-Martinez has been pierced by quite a number of cactus needles in his time. A research botanist and curator of living collections at the Desert Botanical Garden in Phoenix, he’s been studying prickly pears and chollas, which are infamous for their barbed spines, for decades. However, the worst cholla attack he’s ever witnessed came while he was hiking with several friends in Mexico. As they strolled through a cholla forest, one of the group members discovered a chunk of cactus stuck to the tip of his shoe. He tried kicking his foot out to dislodge the spiny hitchhiker. Sure enough, most of the cactus flew off—including one piece that shot straight up and became stuck in the man’s upper lip.

Luckily, Puente-Martinez has had a lot of practice figuring how to remove cactus needles from different body parts. “You could see that they were really deep inside his lip,” he recalls. “Every time I pulled one, there was this little stream of blood coming out of the hole; that was pretty bad.”

Most encounters with cacti aren’t quite that harrowing. But the plants are ubiquitous in some parts of the desert, and are also highly popular (and useful) as home decor. They’ve evolved a wide variety of spines to thrive in the unforgiving desert and some can snare you more easily than others. They can also cause painful complications. So it’s a good idea to prepare yourself for a cactus crisis. Luckily, Puente-Martinez and several other experts can offer a number of tips on how to remove cactus needles based on their hard-won experience.

1. Understand how cactus needles work

Cactus needles make a pretty great armor, but they aren’t just there to stab you. These fibrous structures, which are derived from leaves, do a range of other jobs as well. A coating of spines can serve as shade by day or insulation by night. They can also diffuse light similarly to a photography umbrella, says John Trager, curator of desert collections at the Huntington Botanical Gardens in San Marino, California. This ensures that light is distributed over the plant’s entire surface, even if it is growing in a shady spot. Cactus spines collect water too. Some are curved downwards so that any water that condenses on them will drip onto the soil around the roots, while a few have a cork-like texture that absorbs water.

And spines can camouflage a cactus from hungry animals, as with the flattened, twisted spines of the paperspine fishhook cactus that resemble blades of grass. Cactuses are so good at blending in with their surroundings that people sometimes fail to notice them while they are out hiking, Trager says. “Depending on the lighting, you might not recognize that it’s a spiny as it is until you feel it.”

For chollas and prickly pears, spines serve another purpose that makes them especially unpleasant to tussle with. Unlike the pillar-like saguaro or barrel cactus, these species are built from a collection of smaller pieces that are easily snapped off. “Each one of those portions of the stem has the ability to root in the ground and start a new plant,” Puente-Martinez says. “That ability to propagate and disperse like this, that is what has made them so successful in the desert.”

Spines are a key part of this strategy since they allow a cholla or prickly pear pad to snag passing animals. “They might break off a piece of that cactus and then they will drop it somewhere else,” Puente-Martinez says.

The barbs on these spines resemble a line of fishhooks, says Park Nobel, an emeritus professor of biology at the University of California, Los Angeles, and coauthor of The Cactus Primer and several other books on cactuses and agaves. “So if the spine sticks in, any movement of the unfortunate animal makes the spines go further and further into the tissue, thereby encountering more barbs and making movement even more difficult,” Nobel said in an email.

To make matters worse, chollas and their relatives also sport fine, hair-like spines called glochids. Some of them, such as the bunny ears cactus that is native to Mexico, have glochids but lack regular spines, giving them a more harmless appearance. Don’t fall for it. Glochids are barbed and even trickier to remove than larger spines. “They look soft and fuzzy at first glance,” Trager says. “You might be tempted to pet it or touch it and you get a fistful of these little itchy spines.”

2. Assess if the injury is dangerous

You’re extremely unlikely to die from getting speared by cactus spines, but they can do some damage. Puente-Martinez says this is especially true if you stumble and fall on top of them, as very occasionally happens when people attend receptions at the garden and get tipsy.

The spines can also wind up in more sensitive areas after the initial attack. “If you touch that cactus and now you rub your eye or you put your finger in your mouth, if you have those little barbs or those glochids in there, then you really can have a problem,” says Raymond Dieter, a semi-retired cardiothoracic surgeon who volunteers his services at the Tri City Health Partnership Medical and Dental Clinic in St. Charles, Illinois. “Even though you may be stuck in your knee, they might end up someplace else in your body.”

Sometimes, the barbs can painfully irritate the skin or cause an infection. Such was the case for a young woman Dieter and his colleagues encountered who tripped and fell on a cactus while getting up from dinner. It was not long before swelling and redness had set in, says Dieter, who published a study on the incident in the journal Wounds. This reaction can lead to pustules that last for months and can result in little black spots of dead skin that need to be cut out. In some cases, the wound may become infected with the bacteria that cause staph infections or gas gangrene.

That’s not the most likely outcome, though. “Most people are going to do okay,” Dieter says. “They’ll get over it in a few days or a week or two, but in some people it goes on a long time.” Putting a cold pack on your skin right after you’ve been pricked may lessen the severity of the reaction, he adds.

3. Methodically remove the big and small cactus needles

First of all, don’t grab the spines. “It’s a natural reaction,” Dieter says. But “you’re better off not to use your fingers if you can avoid it.”

It’s all too easy to make a bad situation worse, particularly if you try to pull off pieces of cholla with your bare hands. Nobel once saw the aftermath of this decision in a couple in Saguaro National Forest who had fallen victim to the notorious teddy bear cholla. Initially, one of the pair had become stuck on a piece of stem, and when his wife tried to free him, she too was snared.

“The more they struggled the deeper the spines went,” Nobel says. “They were screaming for help walking along the road in an unnatural embrace, holding hands with the tortuous joint.” Nobel was able to free the pair by cutting the spines out with a pair of wire cutters.

Puente-Martinez also recommends removing the chunk of stem the spines are attached to before dealing with the individual prickers, as he did on the occasion in Mexico when his friend’s lip became a pincushion. Use a pair of scissors or pliers to clip the spines attached to the stem, leaving about half-inch segments of spine behind in your skin, he advises. You can also use the teeth of a comb to work the stem and some of the spines free. If the spines are embedded in your hand and you don’t have any tools handy, you can also try bending over, stepping on the stem joint, and tugging your hand free, although this will likely cause a bit more bleeding as the spines are pulled away.

[Related: First aid basics for your adventure in the wilderness]

What you should do next depends on the kind of spine you’re dealing with. You can try working larger needles out with a pair of tweezers. The straight spines found on cactuses like the saguaro are the easiest to pull free, while barbed cholla spears or hooked spines like those found on barrel cactuses will unsurprisingly take a little more work.

Cactus spines will often break when you try to remove them, leaving pieces lodged under the skin. “You’ll know if you haven’t gotten it all because [the area] will remain sensitive to the touch,” Trager says.

You can try digging around with tweezers or a needle to excavate the spine fragment, but they can be translucent and hard to discern. “Often you’ll do more damage trying to poke around with a needle than the spine itself did,” Trager says. “Unless you can actually see the broken base of the spine just under the skin or something it might not be worth doing it.” Soaking in a warm bath with Epsom salt can relieve some of the pain from embedded spines, he says.

The tiny glochids are particularly tricky to remove, and it’s easy to end up with dozens or more stuck in your skin if you touch a cholla or related cactus. When Puente-Martinez finds himself in this situation, he likes to soften the tiny barbs by running the afflicted limb under warm water. He then scrapes the bristles off with a knife, although this technique can leave the tips behind in your skin. “They’re going to bother you for awhile,” he admits. He’s found that tiny tweezers such as those that come with a Swiss Army Knife are ideal for plucking stubborn glochids; the larger tweezers that many people keep in their bathrooms seem to be less suited for grasping the tiny prickles. A magnifying glass comes in handy for this work, too. You can also use something sticky like duct tape to tug the barbs out of your skin.

If you can’t get all the spines or barbs out, don’t worry. In most cases, they will disintegrate inside your body or eventually be pushed out.

“Let’s just say you’ve hit a cactus with your wrist or your arm, and you reach down with your mouth to pull [the spine] out and spit it out,” Dieter says. “You might get the spine, but the glochid might then stick in your tongue, or in your lip, and then you’re going to have that reaction in your mouth or in your lip and you won’t be a happy camper.”

Another painful possibility is that the barb will embed itself in your throat, which is exactly what once happened to Puente-Martinez (and is the reason why he strongly recommends you do not try this method at home, or ever). He had gently grabbed the spine with his teeth and was just about to spit it out when one of the people working on the plants nearby asked him a question.

“I turned around and swallowed the little glochid,” he says. “I had it there for a couple of days; it was really bothering me.” He finally dislodged the glochid by chewing bread. His theory is that as your saliva moistens the blob of bread, it becomes sticky enough to pull out the spine.

The trick served him well again several months ago when he attended a conference and one the other attendees ordered prickly pears for lunch. Apparently, the fruit had not been cleaned quite thoroughly enough, and the man wound up with a glochid lodged in the roof of his mouth. Puente-Martinez advised him to start eating the white bread the server had brought out earlier. After four or five slices, the offending glochid came away.

5. Enjoy cacti … from afar

“Obviously cacti have significant aesthetic appeal to a lot of people, which has caused cactus societies to spring up around the world,” Trager notes. In fact, the plants’ flowers tend to be intensely bright and vivid thanks to the same betalain pigments found in beets and a few other plants.

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Almost three years into the pandemic, the spotlight isn’t just on COVID medicine anymore. While booster shots and take-home antiviral pills gave us new tools to fight the infectious disease, health researchers and drug makers regained momentum in other crucial areas, like organ transplants, STI prevention, and white-whale therapies for alopecia and HIV. At the same time, AI deepened its role as a diagnostic aid, while mental health services got an accessibility boost across the US. We know the pandemic isn’t over—and other pathogens and illnesses are likely lurking undetected—but the progress we make in medical labs, factories, and care centers can help nurse societies back to health before the next storm hits.

Looking for the complete list of 100 winners? Find it here.

Grand Award Winner

AuriNova by 3DBio Therapeutics: A replacement ear that’s made from ear cells

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About 1,500 people in the US are born each year with absent or underdeveloped external ears. Traditional reconstruction techniques might fix the cosmetic issue, but a new 3D-printed ear transplant, called AuriNovo, offers a living substitute. The implant is made with proteins, hydrogel, and a patient’s own cells, giving it far more flexibility than any constructed with synthetic materials; plus, the procedure is less invasive than, say, transplanting tissue from a patient’s ribs. To build the replacement, a surgeon first takes a sample of an individual’s ear tissue to separate and culture the cartilage-making cells. Then, based on a 3D scan of the fully formed ear on the patient, the part is printed with collagen-based “bio ink” and surgically inserted above the jaw. A 20-year-old woman from Mexico was the first to get the implant this June. 3DBio Therapeutics, the New York-based regenerative medicine company behind AuriNovo, hopes to use the technology to one day create other replacement body parts, like noses, spinal discs, and larger organs. 

Paxlovid by Pfizer: The first take-home treatment for COVID-19

Pfizer

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COVID therapies have come a long way since the start of the pandemic, and now include several antiviral drugs and monoclonal antibodies. But Pfizer’s Paxlovid was the first oral treatment for the disease to receive emergency authorization from the FDA, meaning it can be obtained with a prescription. It’s also highly effective: Clinical trials show it reduces hospitalization and death from the virus up to 90 percent more than a placebo. The remedy is a combination of two pills: nirmatrelvir, which prevents the novel coronavirus from replicating, and ritonavir, which causes the body to metabolize nirmatrelvir more slowly. The drug does have downsides—it can interact with other medications and sometimes causes a foul aftertaste. Plus, rare cases of rebound COVID symptoms and positive tests have occurred in people following Paxlovid treatment, although research indicates that the latter might be related to the immune system responding to residual viral RNA. Still, it represents a crucial new safeguard for healthcare providers and the public.

EVO Visian Implantable Collamer Lenses by STAAR Surgical: Combining the perks of contacts and laser surgery

STAAR Surgical

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Most cases of nearsightedness and astigmatism, which is blurred vision caused by an irregularly shaped cornea, can be fixed with laser eye surgery. But the procedure requires some corneal tissue to be removed and often leaves recipients with lingering dry eyes. EVO ICL provides an alternative with a minimally invasive new way to correct or reduce both conditions. During the approximately hour-long procedure, a flexible collagen-containing lens is implanted between the iris and natural lens. The implant is meant to sit in the eye permanently, but can also be plucked out by an ophthalmologist if needed. In published clinical trial results, close to 88 percent of patients reported 20/20 or better and nearly all achieved 20/32 or better distance vision after six months. The lenses also block some UV rays for added protection.

Olumiant by Eli Lilly and Incyte: Long-term relief for severe alopecia

Eli Lilly and Incyte

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More than 300,000 people of all ages in the US live with severe alopecia areata, a condition that causes the immune system to attack hair follicles, leading to patchy baldness on the scalp and elsewhere. Hair loss in the nose and ears can affect patients’ hearing and allergies, and a lack of eyelashes can leave people vulnerable to eye irritation from dust. Olumiant, the first medication to secure the FDA’s approval for severe alopecia, can help hair grow back over the entire body. It belongs to a group of drugs called JAK inhibitors, which block certain inflammation-promoting enzymes. It was originally greenlit by the agency in 2018 to treat some forms of rheumatoid arthritis, but in clinical trials for alopecia, it helped roughly a third of participants to regrow up to 80 percent of their hair by 36 weeks, and nearly half after a year. Other JAK inhibitors in development could provide alternatives for patients who don’t fully respond to Olumiant.

AIR Recon DL by GE Healthcare: Sharper MRIs in half the time

GE Healthcare

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Laying motionless for an hour or longer in a magnetic scanner can be a claustrophobic and sometimes nauseating experience. A next-level neural network by GE Healthcare reduces the stress on patients, while filtering out visual noise from movement or faulty processing. The software combs through raw radio-wave data from MRI machines and turns the most accurate bits into high-resolution 3D images. Originally, the AI-reconstructed images had to be stitched together—but the updated tech, which received FDA approval this September, delivers in one go. The speedy precision can cut exam times in half, help hospitals and clinics serve more patients, and possibly improve the rate of diagnosis by giving radiologists a much cleaner view of tissues, bones, masses, and more.

ONE Male Condom by ONE: Latex that works for anal sex

ONE

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At first glance this condom isn’t all that different from those by other brands. It’s made from natural latex, comes in three thicknesses, and has a wide range of sizes for best fit. But the contraceptive is the first to also be clinically tested for STI protection during anal sex—and has proven to be extremely effective. In studies involving 252 male-male couples and 252 male-female couples, the condoms had a less than 2-percent chance of breakage, slippage, discomfort, and adverse events (which included urinary tract infections and bacteria and viruses spread during sex). With such a healthy showing, the company earned the FDA nod to label the product as “safe for anal sex.” With widespread availability, there’s hope that the condom can help beat back a record rise in chlamydia, gonorrhea, syphilis, and other STIs.

Bivalent COVID-19 vaccines by Moderna and Pfizer-BioNTech: A one-shot-fits-all approach

Ringo Chiu, AFP via Getty Images

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One of the niftiest features of mRNA vaccines such as Moderna and Pfizer-BioNTech’s COVID shots is that they can be tweaked and scaled up quickly to keep up with an ever-changing virus. This August, the FDA authorized the first bivalent COVID boosters, modified with new genetic data to target both the original version of SARS-CoV-2 and the Omicron sub-variants BA.4 and BA.5. Just how much added protection the bivalent shots offer against the latest versions of COVID remains to be seen, although in early results, the Pfizer-BioNTech booster increased antibodies against the BA.4 and BA.5 sub-variants by up to 11 times, while the Moderna booster did so by up to 15 times. Experts anticipate that the bivalent COVID vaccines, which are available to all adults and children ages 5 and older in the US, could save thousands of lives if the virus surges again this winter. 

Umbilical cord blood transplant for HIV by Fred Hutchinson Cancer Research Center and Weill Cornell Medicine: The right cells for viral resistance

NIH

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There are now three official cases of patients in long-term HIV remission—but this one might be the most promising for the millions around the world living with the virus. In 2017, an unidentified American received a blood transplant packed with genes that were resistant to the pathogen behind AIDS. More than four years later, her doctors at Weill Cornell Medicine confirmed that the procedure at Fred Hutchinson Cancer Research Center had indeed made her free of the disease. The miraculous sample was specifically taken from a relative’s umbilical cord blood cells, which were still in the process of maturing and specializing, making it easier for the transplant to take. Previous attempts to cure the disease depended on bone marrow donations that carry a mutated gene only known in Northern Europeans. This alternative treatment makes transplants more accessible for patients from other ethnic backgrounds, so their bodies can fight HIV in the long run as well.

988 Suicide and Crisis Lifeline by SAMSHA: Streamlining the call for help 

SAMHSA

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When you have a general emergency, you might call 911. But for people experiencing a mental crisis, the number has been a lot less intuitive. This July, however, the Suicide and Crisis Lifeline, run by the US Department of Health and Human Services since 2005, fully switched over to a three-digit code that’s easy to punch in: 988. The shortcut was years in the making, but required major collaboration with the Federal Communication Commission to connect every phone service provider to the alternative number. Since it went live, officials have reported shorter hold times and a 45-percent increase in use compared to August 2021, including on a specialized veteran hotline. The service shakeup also came with $177 million for states and tribes to support the transition in different ways, like alleviating surcharges, setting up call centers, and integrating crisis relief with existing or new emergency responses.

eCoin Peripheral Neurostimulator by Valencia Technologies: A discreet implant for bladder control 

Valencia Technologies

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Pads, vaginal seals, and skin patches can be a burden for anyone who has to deal with urinary incontinence on a daily basis. A new electrode device, about as small as a nickel and implanted above the ankle, nips the issue in the bud in a more private and convenient way. Incontinence typically occurs when the muscles in and around the bladder contract too often or too much. To prevent leaks and constant trips to the toilet, the eCoin sends low-key shocks through the tibial nerve, targeting the pelvic organs and relaxing the bladder wall. A doctor can control the intensity of the pulses with a remote, making the device more customizable for a broad range of patients. Neurostimulators have become a vanguard treatment for different nervous system conditions, including chronic back pain and even paralysis—but few are so adaptable as this.

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On July 13, the US Department of Health and Human Services (HHS) notified pharmacies that refusing to fill prescriptions for medicines containing ingredients that can induce abortion or prevent pregnancy could be in violation of federal civil rights law.

The new guidance, which is aimed at the roughly 60,000 retail pharmacies across the country, breaks down how withholding certain medicines would discriminate against customers on the basis of sex or disability. These drugs include contraceptives, miscarriage treatments, and several non-abortion medications used to treat conditions like rheumatoid arthritis, ulcers, and multiple sclerosis. 

[Related: The US can’t agree on what a life-saving abortion is]

Experts are concerned that some pharmacists in states that have passed abortion restrictions might be unwilling to dispense common medications, even when they have been prescribed for other purposes besides reproductive healthcare. “Reproductive rights are not only a women’s issue, nor are they only an [obstetrics] issue,” Sara C. LaHue, an assistant professor of clinical neurology at the University of California, San Francisco, said in an email. “Restrictions on abortion will affect the care provided by the vast majority of medical specialties in the US.” 

Abortion medicines with many uses

The HHS document describes several situations where refusing to fill a prescription can be discriminatory. These include prescriptions for mifepristone and misoprostol, which are used for both abortion and miscarriage care. Mifepristone blocks hormones necessary for a pregnancy to continue, while misoprostol causes the cervix to soften and the uterus to contract and empty itself.

“Because they’re the meds also used for first-trimester abortion, some pharmacists have reportedly not dispensed them to patients who are having a miscarriage, despite a valid prescription, for fear of running afoul of their state abortion laws,” Katharine O’Connell White, an associate professor of obstetrics and gynecology at the Boston University School of Medicine and gynecologist at Boston Medical Center, said in an email. “Restricting access to mifepristone and misoprostol takes away the choice of people who are having a miscarriage to manage their pregnancy loss with medication, and avoid a procedure. This makes the already difficult experience of pregnancy loss even worse.”

Misoprostol is also prescribed to people who are enduring very heavy bleeding during a miscarriage. If these patients aren’t able to fill a prescription for misoprostol at the pharmacy, White wrote, they face a higher risk for hemorrhaging, needing a blood transfusion, or dying.

Misoprostol was developed in the 1970s to treat stomach ulcers. It’s still used to prevent ulcers related to long-term use of anti-inflammatory medications such as ibuprofen, White explained. The drug protects the stomach by reducing acid secretion, increasing mucus production, and changing blood flow in the lining of the organ. 

[Related: Aspirin has long been prescribed to prevent heart attacks. Now experts say it shouldn’t.]

Another medication with varied uses is methotrexate. The drug was first introduced in the 1940s as a chemotherapy agent due to its ability to prevent cells from making and repairing DNA, and today is used to treat a variety of cancers. Methotrexate also suppresses the immune system and is prescribed for multiple sclerosis, myasthenia gravis, rheumatoid arthritis, psoriasis, and Crohn’s disease, LaHue explained. 

Additionally, methotrexate can be used to end ectopic pregnancies—which occur when a fertilized egg grows outside the uterus—by disrupting the metabolism of folic acid to halt cell growth. “If a pharmacist doesn’t release this medication, a patient is then forced to have a surgical procedure where they will likely lose one of their fallopian tubes,” White wrote. Without surgery, an ectopic pregnancy can rupture and lead to hemorrhaging and death. “Simply put, abortion care cannot be separated from the rest of pregnancy care,” she added. 

According to a recent statement from the Arthritis Foundation, people in states like Texas are reporting difficulties getting their prescriptions for methotrexate filled. If a pharmacy refuses to fill a prescription for methotrexate because it will end an ectopic pregnancy, it may be discriminating on the basis of sex, according to the HHS. And if the pharmacy refuses to fill a prescription for methotrexate to treat a customer’s rheumatoid arthritis because of its other uses, it may be discriminating on the basis of disability, the department’s policy states. Similarly, if a pharmacy refuses to fill a customer’s prescription for mifepristone and misoprostol to manage a miscarriage, or misoprostol for severe and chronic ulcers, it might be discriminating on the basis of sex and disability, respectively.

Some pharmacies are also refusing to stock or dispense contraceptives based on misconceptions around how the treatments work. Birth control pills, morning-after pills, IUDs, and other contraceptives prevent pregnancies from taking place—they don’t cause abortions, White underscored. If a pharmacy refuses to fill a prescription for emergency or hormonal contraception, but provides other contraceptives such as condoms, it could count as sex-based discrimination, per the HHS. 

Ripple effects of reversing Roe v. Wade

The Supreme Court’s recent decision to end the longstanding right to abortion in the US might also make certain non-abortion medications that can affect fetal development less accessible, explained LaHue, who published an article in the journal JAMA Neurology earlier this month about how the ruling will impair the ability of neurologists to properly care for their patients. 

Several common medications for neurological conditions have teratogenic effects, which means they can interfere with the development of an embryo or fetus. These include the drugs teriflunomide and fingolimod for multiple sclerosis and an antiseizure medication called valproate. Often, people with the ability to become pregnant need to use contraception to be prescribed teratogenic drugs, LaHue explained. 

“However, no contraceptive is 100 percent effective, and some medications (especially antiseizure drugs) may even reduce the efficacy of contraceptives. So, unintended pregnancies with these medications are realistically unavoidable,” she wrote in her email. “Physicians may be unwilling to prescribe them in states where abortion is banned, and we may also see increases in serious birth defects in these states.”

Many cancer drugs can also be teratogenic. This raises the possibility that in some areas a sick patient who becomes pregnant won’t be eligible for certain treatments. “Restrictions on reproductive healthcare will limit management options for women with life-threatening diagnoses during pregnancy,” LaHue noted. 

An additional concern includes drugs that haven’t yet been shown to be safe in pregnancy. Many medications lack data addressing this question, LaHue mentioned. “In these cases, it is safer for the fetus to avoid such medications, but it may mean that treatment is being withheld from the mother not because of evidence of harm, but because of lack of evidence,” she added. “We need pharmaceutical companies to study teratogenic risk profiles to reduce disparities in care across medical specialties.”

Meanwhile, HHS has emphasized that it is committed to “vigorous enforcement” of civil rights laws to protect the health of people who are pregnant or experiencing miscarriages. Among its civil rights enforcement responsibilities, it is responsible for protecting the rights of women and pregnant people in their ability to access care that is free from discrimination,” the agency wrote in its new guidance for pharmacies. “This includes their ability to access reproductive health care, including prescription medication from their pharmacy, free from discrimination.”

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The 1947 children’s novel Misty of Chincoteague opens with a dramatic account of a small herd of horses escaping from the wreck of a colonial-era Spanish galleon. According to local folk stories, these same hardy animals thrived on the islands of Chincoteague and Assateague, which lie off the coasts of Maryland and Virginia. 

Scholars have long debated the likelihood of this origin story about the population of feral ponies that have made the islands famous. A new genetic analysis of a 16th-century horse tooth from the Caribbean doesn’t settle this question, but does offer some indirect support for the shipwreck tale’s plausibility.

Researchers found that the tooth fragment, which was discovered in present-day Haiti, belonged to a horse of southern European origin. Additionally, the specimen is most closely related to the Chincoteague pony breed, the team reported today in the journal PLoS ONE. 

“This helps us to have a better idea of what the origins of these early colonial horses are,” says Nicolas Delsol, a zooarchaeologist at the Florida Museum of Natural History in Gainesville and coauthor of the findings. “There is some documentary evidence from the historical literature stating that horses were boarded in southern Spain, where most of the first expeditions came from, but it’s always interesting to see how accurate these early colonial chronicles are.”

Michelle Delco, an equine orthopedic surgeon and assistant research professor at the Cornell University College of Veterinary Medicine who wasn’t involved with the research, said the findings “fill in a major gap.” 

“There is a lot of historical evidence that the modern domestic horse was introduced to the Americas from the Iberian peninsula around 1500, but we have surprisingly limited archeological and scientific evidence about this,” she said in an email.

[Related: Ancient sea creatures pioneered the gallop]

The horse family (whose members are known as equids) evolved in North America roughly 50 million years ago and spread to Eurasia around 2.5 million years ago. Equids disappeared, along with many other large animals, from the Western Hemisphere around 10,000 years ago. In the late 15th century, however, domesticated horses were brought to the Americas during the European invasion.

“Because they were so central to the European lifestyle, they brought [the horses] with them,” Delsol says. “They first were introduced in the Caribbean islands, where the first European settlements were, and then diffused throughout the continent along with the developments of European colonization.”

The tooth he and his collaborators analyzed was excavated in 1980 from a 16th-century town known as Puerto Real on Hispaniola, the island shared by the Dominican Republic and Haiti. The specimen dates to a period when occupation was sparse after Spanish authorities ordered the island’s northern ports abandoned in the 1570s in response to persistent pirate raids and smuggling. 

The tooth fragment was initially misidentified as belonging to a cow. But when Delsol examined DNA from the specimen, he realized that the tooth actually came from the molar of an adult horse. “Since it was the earliest horse genome that we had, we decided it was worth working a bit more on it and seeing what it could tell us,” Delsol says.

He and his team investigated a kind of genetic material known as mitochondrial DNA, which is passed down only through the maternal line. Mitochondrial DNA isn’t confined to the nucleus of a cell, which means it’s more abundant and easier to collect from ancient samples than nuclear DNA, Delsol says.

“Domesticated horses originated from a relatively small number of male ancestors and a great diversity of female ancestors,” said Delco, who studies the role of mitochondria in health and disease. “So, by fully reconstructing the mitochondrial genome of this early Caribbean horse, the authors could very specifically ‘place’ this individual in space and time—meaning both in the context of its origins from the Eastern Hemisphere, as well as its closest relatives among modern horses in the Americas.” 

The researchers determined that their specimen represents the oldest complete mitochondrial genome of a domestic horse in the Western Hemisphere. When they compared the Puerto Real horse’s genetic material with that of other breeds from around the world, the team concluded that it belonged to a group whose members are found in Central Asia, Southern Europe, and the Middle East—but not northern Europe. This suggests that the Puerto Real horse hailed from the Iberian Peninsula, which is occupied by Spain and Portugal. 

Additionally, the Puerto Real horse’s closest relatives turned out to be the feral ponies of Chincoteague and Assateague. This doesn’t necessarily mean that the ponies’ ancestors fled from a Spanish shipwreck, Delsol emphasizes, but it “gives more historical accuracy to this story.” 

Delco, who grew up reading the tale of Misty of Chincoteague, was excited to see a study put actual data and genetic findings behind these fables. “At the age of about 10, I persuaded my parents to take me to the Assateague Island National Seashore and will never forget the rainy, sandy week we spent with the wild ponies,” she said. “This scientific manuscript suggests the legendary origin story of the Chincoteague pony is true. It’s not often that reading a science paper gives me goosebumps.”

Beyond folk stories, Delsol adds, the ties between this Caribbean horse and the Chincoteague ponies may reflect an early Spanish presence along the Atlantic coast of North America. 

[Related: Ancient wolf DNA is being used to sniff out where our love story with dogs began]

“What we consider the different colonial spheres of influence—the French, the British, the Spanish—at that time weren’t completely watertight,” Delsol says. “Everybody was pretty much everywhere.”

However, the team acknowledges that the findings focus on a single horse and only include its mitochondrial DNA, which means that the tooth  “only gives us the story of the maternal lineage,” Delsol says. “To be more thorough, we would include an analysis of the paternal lineage.” Although DNA degrades more quickly in tropical climates, he’s successfully extracted snippets of nuclear DNA from similarly-aged cattle specimens and suspects it will be possible to do the same with the Puerto Real horse. Delsol and his team also plan to expand their analysis to the remains of other horses from Puerto Real.

The findings demonstrate how fragments of genetic material from organisms that died a long time ago, known as ancient DNA, can shed light on historical events.

“Ancient DNA is quite often associated with very remote periods of time and really ancient specimens, but it can also be pretty useful to clarify more recent history,” Delsol says. “Part of this history is the colonization of the Americas and how animals were a central part of the establishment of Europeans on the continent.”

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Nearly 20 years ago, scientists discovered a fossil in the Canadian Arctic that represented a transitional stage between marine and land-dwelling animals. Tiktaalik roseae—nicknamed a “fishapod,” or a fish with limbs—used its muscular front fins to prop itself up in shallow waters or on mudflats. 

But the course to dry land doesn’t always run smoothly. At least one close relative of Tiktaalik decided to return to the life aquatic, researchers reported on July 20 in Nature. A smaller fossil excavated from the same area as Tiktaalik shares some features with its land-curious cousins, but it has a fin much better suited for swimming than crawling. The ancient lobe-finned fish, which the team named Qikiqtania wakei, sheds light on a mysterious chapter of vertebrate evolution.

“This is a really unexpected variation in the group right at the cusp of the water-land transition,” says Thomas A. Stewart, an evolutionary biologist at Pennsylvania State University and coauthor of the findings. “It shows that there was a diversity of animals doing all kinds of different things.” 

Alice Clement, an evolutionary biologist and paleontologist who studies early vertebrates at Flinders University in Adelaide, Australia, described the work as a “lovely study.” 

“New finds such as this help us to piece together the sequence of characters acquired in the lead up to the colonization of land by our terrestrial ancestors,” she said in an email. More samples of this enigmatic group, she added, would help “confirm the authors’ interpretation about a possible ‘return to the water.’” 

The Qikiqtania fossil was first collected in 2004 on southern Ellesmere Island in Nunavut. “It was found because of bad weather,” recalls Neil H. Shubin, an evolutionary biologist at the University of Chicago and another coauthor of the study. He and his collaborators couldn’t access the site where, several days later, they would discover Tiktaalik, so the team searched for fossils near their camp. Among the finds was a block of rock with scales and part of a jaw exposed. The specimen “kind of sat in the drawer for 15 years,” Shubin says, before his colleagues began to examine it in detail. 

[Related: This ancient bony fish was a sexual pioneer]

The team initially suspected that the fish was a young Tiktaalik, Stewart says. But when they used CT scanning to get a better look at the fossil embedded within the rock, they realized that the creature’s upper arm bone had some unique characteristics.

“The surprise for us really was in the shape of the humerus, which suggested that this is not an animal that could support its body with its fins like Tiktaalik and like tetrapods,” Shubin says, referring to four-limbed animals with backbones. “This is an animal probably more suited for open-water habitats.”

The fossil included the lower jaws, partial upper jaws, fragments of neck bone, scales from various parts of the body, and the left pectoral fin. Qikiqtania was named for the Inuktitut word Qikiqtaaluk/Qikiqtani, the region where the fossil was found. The researchers estimate that it lived roughly 375 million years ago, making it slightly older than Tiktaalik. Qikiqtania would have reached about 2.5 feet in length and had an elongated body with a broad and paddle-like fin, sharp teeth, and eyes perched on top of a flat head.

To determine where Qikiqtania belonged on the prehistoric family tree, the researchers used the CT scans to create 3D reconstructions of the fossil and compared it to 12 other species. The team calculated how closely the anatomy of Qikiqtania resembled that of other early vertebrates by comparing 125 traits between the fossils.

“This animal is related to the first limbed vertebrates—the first animals with hands and feet,” Stewart says. However, “its humerus is quite distinct from other creatures that are closely related to it.”

In Qikiqtania, this arm bone is relatively small and shaped like a boomerang, whereas Tiktaalik has a blocky, angular humerus. Additionally, Qikiqtania lacks the ridges and crests in the bone that its relatives have where pectoral muscles were attached. “It’s not a humerus that could do a pushup,” Shubin says. 

Some evolutionary biologists are skeptical these unusual features represent a truly new find. Per Ahlberg, who studies vertebrate evolution at Uppsala University in Sweden, isn’t convinced that Qikiqtania is a different species from its cousin Tiktaalik. One possibility is that the distinctive humerus is “lightly ossified and crushed, which could affect the interpretation,” Ahlberg said in an email, adding that he hopes to examine the bone in more detail.

Still, he said, the new report is “an interesting paper that puts forward some novel ideas.”

[Related: An archerfish family tree is the best shot yet at the evolution of sniper fish]

Other species ancestral to Qikiqtania had fins that could support their bodies, suggesting that Qikiqtania returned to the water after its relatives crawled onto land.

“It’s a specialization which is fascinating because it’s showing that the transition from life to water to life on land is a bit more complex,” Shubin says. “You have some creatures evolving to walk on land or the water bottom, and others are evolving to open-water habitats; it’s going both ways.”

It’s not clear why Qikiqtania took to the water, but the researchers have a few guesses. “There’s a lot of meat in the water,” Shubin says. Qikiqtania’s skull has a few features that it shares withTiktaalik, indicating the fish could both bite and suck—a powerful edge while hunting. “This animal was probably able to do that as well,” Shubin speculates. “It had certain advantages to return to water in that way.”

The researchers hope to find more complete Qikiqtania specimens on future expeditions. A well-preserved shoulder or pelvis could reveal how the creature moved through the water. “What was its gait, how did it use the hind fins, how did it paddle?” Shubin says. “We don’t have enough of the anatomy to know those details.”

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Today’s mammals and birds enjoy numerous advantages from being able to generate their own body heat. Warm-blooded animals have high metabolic rates that allow them to be more active than creatures that depend on their surroundings for warmth. They can travel faster, undertake long migrations, and inhabit chilly terrain. 

Now, a report published today in Nature gives new light to a long-standing puzzle as to when mammals evolved this vital trait. To help pin down the metabolic mystery, the group of paleontologists tapped a surprising piece of anatomy: the inner ear—the shape of which is influenced by an animal’s body temperature. The team examined the inner ears of fossilized and modern species, and estimated that warm-bloodedness, or endothermy, emerged in the group around 233 million years ago during the Late Triassic Period, before the first true mammals evolved.  

“When mammals and their ancestors became endothermic has been one of the great unsolved mysteries of paleontology for a really long time; it’s such a distinct feature of mammals and it’s wrapped up in so many aspects of our physiology and biology,” says Kenneth D. Angielczyk, a curator of fossil mammals at the Field Museum of Natural History in Chicago. “We’ve been able to pinpoint when mammal-style endothermy evolved much more precisely and much more accurately than what was possible previously.”

Previous estimates for when endothermy emerged have varied widely and are based on fossil evidence for traits seen in many warm-blooded animals such as rapid growth or nocturnal activity. However, these traits aren’t necessarily “exclusive indicators” of endothermy, Angielczyk says. For example, the ability to maintain a core body temperature could enable an animal to stay active at night, when basking in the sun isn’t an option, but there are also plenty of nocturnal reptiles and amphibians found in hot climates. 

“We believe that the specific adaptations to the mammalian inner ear, namely a part of the ear called the semicircular canal system, provides a more conclusive answer,” says Ricardo Araújo, a paleontologist at the University of Lisbon’s Institute of Plasma and Nuclear Fusion in Portugal and another coauthor of the findings.

[Related: Were dinosaurs warm-blooded or cold-blooded? Maybe both.]

The semicircular canals are a series of coiled tubes filled with a liquid that help an animal track the movements and spatial location of its head, which is crucial for navigation, balance, and motor coordination. The fluid in these canals becomes runnier at warmer body temperatures. This means that, in order to maintain regular movement and balance, the semicircular canals of warm-bodied animals need to be a different specific shape and size for that thinner, sloshy liquid than in animals with colder body temperatures and thicker inner ear fluid. 

“The tuning of the inner ear system needs to be really well optimized according to the temperatures that the system is going to be exposed to,” Araújo says. “If you need to run [from a predator] and your inner ear system doesn’t know where your head is, then you’re going to die, you’re going to be eaten.” 

Canals fine-tuned for warm temperatures suggest that their animal owner can create its own internal heat. By looking at the shape and relative size of the inner ear, the researchers say, it’s possible to predict whether an animal was warm- or cold-blooded. 

Armed with this information, the research team sought to investigate the origins of endothermy in mammals by  examining CT scans of the inner ears in both fossil and modern skulls. The analysis included 341 species, including 234 modern mammals, reptiles, birds, and amphibians, as well as 64 prehistoric species that included close relatives of early mammals.

The team observed that the most ancient mammalian ancestors had long, thick semicircular canals, resembling those of cold-blooded modern reptiles and amphibians. By contrast, modern warm-blooded mammals had much thinner canals that were smaller relative to their body size. 

When the team used these inner ear measurements to calculate the animals’ body temperatures, they found that their estimates for modern species were very similar to published body temperature data. Based on their body temperature estimates for extinct animals, the team concluded that the transition to warm-bloodedness took place over a 1 million year period,  before the first true mammals emerged roughly 200 million years ago. “The tempo of the evolution of endothermy was surprisingly fast, geologically speaking,” Araújo says.

Warm-bloodedness emerged during the Carnian pluvial episode—a period of climatic instability marked by hot temperatures and heavy rains. Being able to maintain a stable body temperature may have helped the ancestors of mammals cope with the upheavals in their environment, Angielczyk says.

The study authors suspect that the emergence of endothermy in mammals is tied to genetic changes that resulted in a physiological process that allowed the animal to become “a factory that’s continuously pumping heat,” and the evolution of fur for keeping that precious heat from dissipating into the surrounding air, explains Araújo.

[Related: The secret to these bats’ hunting prowess is deep within their ears]

The new technique is more accurate for assessing groups of animals than predicting body temperature in individual species. Definitively identifying specific species that were cold- or warm-blooded would give an even more precise timeline, Angielczyk acknowledges. For future research, he and his team plan to extend their technique to more extinct creatures. “It will be interesting to do more sampling, particularly around the origin of mammals,” Angielczyk says, and “to apply this approach to other animals in the fossil record.” 

Roger Seymour, an evolutionary physiologist at the University of Adelaide in Australia who wasn’t involved in the research, says that scientists have debated how mammals became warm-blooded for at least 60 years. The new results could help move the conversation forward.

“The amount of work involved in getting the data and analyzing it is enormous,” Seymour said in an email. “The data set is very valuable.” 

Seymour and his team have previously proposed that high metabolic rates developed even in the shared ancestor of birds and mammals nearly 300 million years ago. More evidence will be needed, he said, to demonstrate that the anatomical changes in the semicircular canals reported in the new paper coincided with the advent of full-blown endothermy, rather than occurring afterwards.

Linking the inner ear structure to endothermy was “an eyeopener,” says Seymour. “This paper is definitely a new approach to the question of the origin of endothermy in the mammal lineage.”

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Since the COVID-19 vaccines first began rolling out last winter, some recipients have noticed unexpected menstrual bleeding after getting the shots. A survey of tens of thousands of adults published today in the journal Science Advances confirms that this experience is relatively common.

“We think it’s really important to be clear and honest and responsive when something like this does come to the forefront, and so we want to reassure people that this is something that might happen, it should be transitory, it should be a short-term effect,” says Katharine Lee, a biological anthropologist at Tulane University. “The main takeaway is that this is a real factor, and it shouldn’t scare people away from the vaccine.”  

She and her collaborators surveyed a gender-diverse group of more than 39,000 pre- and post-menopausal people around the world. Forty-two percent of participants with regular periods bled more heavily than usual after vaccination, while 44 percent reported no change. 

These numbers aren’t meant to be indicative of how prevalent such irregularities are in the general population, the authors note. “But the information we have about the characteristics of folks within that sample being more or less likely to experience this are still very, very useful and valuable,” Lee says.

[Related: COVID deaths in pregnant people in the US are flying under the radar]

She and her collaborators became curious about the COVID-19 shots’ effect on menstruation after several of them experienced unexpected bleeding. “We decided to look into this a little bit more because so many people were starting to talk about it on social media, and we thought it was important to capture and start to understand what was happening,” Lee says.

“This is in fact a real lived experience, there are real biological mechanisms that would underpin and predict a finding like this, and we shouldn’t be surprised that the uterus, which is an immune organ, is going to be impacted by an immune treatment like the vaccine,” says Kathryn Clancy, a biological anthropologist at the University of Illinois at Urbana-Champaign and another coauthor of the findings.

“The uterus as an organ is already very closely tied to the immune system,” she explains. The uterus must be able to contend with pathogens from outside the body while also allowing sperm and embryos to survive. “It’s not quite ‘open for business,’ but the cervix is not like a full barrier; there has to be some way in which the uterus is doing something to fight infection,” Clancy notes. 

Menstruation itself is also an inflammatory process. “Any system in the body that … has to repair itself many times or that is in any way connected to the immune system has a chance of having some kind of transient side effect associated with something like a vaccine,” Clancy says.

[Related: How to track your period—without an app]

The team released a web survey in April 2021 as vaccines were reaching widespread distribution in the US, hoping for 500 to 1,000 responses. “We had more than that within the first hour or two of the survey being open,” Lee says. “I think there was really a huge need for people to want to share these experiences, because people don’t normally get to talk about their periods; it’s sort of a taboo subject to bring up.”

The researchers ultimately focused their analysis on 39,129 respondents who were adults, fully vaccinated, and hadn’t caught COVID-19. Among participants who regularly menstruated, the proportion who experienced unusual bleeding was similar to those who noticed no change. A small minority also reported lighter periods. Among those who don’t typically menstruate, 71 percent of people on long-acting reversible contraceptives such as the IUD, 39 percent of people on gender-affirming hormones, and 66 percent of postmenopausal people reported breakthrough bleeding. 

Respondents who were Hispanic or Latinx, had a diagnosed reproductive condition such as endometriosis, had been pregnant or given birth in the past, or experienced fever or fatigue after vaccination were all more likely to report heavier menstrual flow than their peers. The type of vaccine didn’t seem to have an effect either way.

“I’m glad this innovative research on menstrual health is being conducted,” Leslie Farland, an epidemiologist at the the University of Arizona Mel and Enid Zuckerman College of Public Health who has studied how SARS-CoV-2 infection can influence menstruation, said in an email. “Traditionally, the emphasis in vaccine surveillance has been on pregnancy and fertility with little emphasis on gynecologic or menstrual health.” 

Clancy suspects that menstrual irregularities following vaccination are much less prevalent in the population at large than in the researchers’ sample. Individuals who noticed some kind of menstrual change following vaccination were probably more likely to take the survey than those who didn’t. Had pharmaceutical companies conducting vaccine trials recorded data on menstruation, Clancy notes, they might have been able to capture the effect across a broader swath of people than was possible with a survey. 

Changes to menstrual bleeding generally aren’t uncommon, dangerous, or indicative of changes to fertility, the researchers emphasized in the paper. COVID-19 vaccines are safe to receive while pregnant or breastfeeding and there is no evidence that vaccines of any kind harm a person’s fertility, according to the Centers for Disease Control and Prevention. Infection with the novel coronavirus itself, however, can cause fertility problems.

[Related: The truth about COVID, vaccines, ED, and fertility]

Nonetheless, it’s important to understand how vaccines might affect menstruation so that people aren’t caught unaware. 

“This unexpected bleeding runs the risk of psychological distress for those who experience gender dysphoria with menstruation and physical harm for people for whom managing menstruation in public is dangerous,” the researchers wrote in the paper. Breakthrough bleeding among postmenopausal people can also be an early sign of cancer, they said. “When possible side effects to a medical treatment are not shared with the clinical or patient population, it may lead to unnecessary, painful, and expensive diagnostic procedures.”

Many people who filled out the questionnaire felt that their healthcare providers brushed off their concerns. “One of the things we found really compelling as we started reading the free responses in our study was the number of people who felt betrayed, whose trust was reduced, who were really hurt by they kinds of experiences they had when they tried to tell people they had this increased bleeding and then people dismissed their experience,” Clancy says. 

Recognizing the impacts of vaccines on periods will help bolster trust between people who’ve experienced them and healthcare providers, she and her colleagues concluded. The team is now conducting a follow-up survey to determine how long changes persisted after vaccination.

The COVID jabs aren’t the first immunization to be linked to anomalies in menstruation, Farland wrote in her email. “It is my hope that in the future, information on changes to the gynecologic and menstrual health should be collected regularly as part of vaccine surveillance.” 

Amelia Wesselink, an epidemiologist at the Boston University School of Public Health whose work has indicated that COVID-19 shots and other vaccines don’t impair fertility, described the new study as an important first step. 

“Because menstrual health is not evaluated in vaccine trials, we lack any systematic data on post-vaccine change,” she said in an email. “This type of survey, designed to listen to the experience of menstruating people, is essential in developing hypotheses for future research.”

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Woodpeckers lead a pretty high-impact lifestyle. When they smash their beaks against trees, they’re subjected to forces that would easily knock a person silly. Many ornithologists have assumed that the shape and composition of woodpecker skulls have evolved to dampen this shock, but a new analysis indicates that the birds don’t have—or need—this kind of protection. 

Researchers filmed three species of captive woodpeckers pounding away, and found that their heads behave like “stiff hammers” to peck as efficiently as possible. If the birds had shock-absorbing skulls, the hardware would just get in the way, the team concluded. What’s more, because woodpecker brains are so small, they don’t sustain the kind of damage that a human would endure from similar impacts, the authors reported today in Current Biology.

“It seems like actually the impacts are not as severe as people had just assumed,” says Wesley Hochachka, an ecologist at the Cornell Lab of Ornithology who wasn’t involved in the research.

Woodpeckers drum into trees to find food, build nests, and communicate during the breeding season. “This is basically what the woodpeckers need to do to survive, so if they’re not sleeping and they’re not resting, they are probably pecking on something,” Hochachka says. “There’s no respite from it at all.”

[Related: How polygamy makes acorn woodpeckers master survivalists]

When a woodpecker strikes its beak into tree bark, its head abruptly decelerates. This kind of impact can cause brain tissue at the front of the skull to compress while tissue at the back is pulled away from the braincase, says Sam Van Wassenbergh, a biomechanist at the University of Antwerp in Belgium and coauthor of the paper. 

“It’s a logical thing to expect that woodpeckers are adapted to not get any headaches, or to not get a concussion during their daily activities,” he says. 

Many researchers believed that woodpeckers have some kind of cushioning in their skulls that acts like an airbag or helmet. Some proposed that spongy bone between the beak and braincase, or muscles surrounding the beak, could minimize the shock from the impact. 

But this idea presents a paradox. “The birds accelerate their head up to a certain speed, giving it this movement energy they want to transfer to the tree to damage or hit away parts of the bark,” Van Wassenbergh says. Yet a shock-absorbing skull would also lessen the energy that reaches the tree. “People don’t use hammers that have a shock absorber built into it; it just makes hammering quite inefficient,” Van Wassenbergh explains further.

To get to the bottom of the mystery, the researchers captured more than 100 high-speed videos of six individuals from three species pecking as fast as about 16 feet per second. The birds—black, pileated, and great spotted woodpeckers—covered a range of body sizes and geographies. The team tracked the movements of several points on the beak, eye, and skull to understand the movement of the braincase. 

“If there would be any shock absorbed, either by beak movement or in this spongy bone zone, you would expect that the brain has a slower deceleration than the beak,” Van Wassenbergh says. “There was actually no difference between the beak and the brain in terms of these movement patterns, which means that [their heads] function as kind of a stiff hammer. It makes sense if you want to optimize your pecking performance.” 

[Related on PopSci+: Metal music is good for you]

The researchers next used computer models to explore how a shock-absorbing zone between the beak and braincase would actually affect the birds’ pecking abilities. They calculated that such padding would significantly reduce the penetration of the beak into wood.

“With these data we show that it’s a pure waste of energy to have a shock absorber there,” Van Wassenbergh says. “You could achieve the same effect as a shock absorber by just hitting the tree less violently.”

Finally, he and his collaborators investigated what might be preventing the woodpeckers from becoming concussed. Using computer simulations of a water-filled cavity to represent avian and human brains, they found that woodpeckers aren’t subjected to as much damaging pressure as a bulkier human brain would be if it experienced the same deceleration. 

“”For humans we know approximately when a concussion can be expected, and we used this as a reference to compare the pressure loading for the woodpeckers.” Van Wassenbergh says. “The [birds] still have some safety margin before they would get a concussion.” In fact, the woodpeckers would need to hit the wood twice as fast as observed, or hammer into wood four times stiffer than they typically encounter, to suffer this kind of injury.

Van Wassenbergh notes, this isn’t the first time that researchers have raised the idea that woodpeckers don’t need special protection against brain trauma but his team’s dataset offers a more detailed picture of how the industrious birds smash their heads on tree trunks without injuring themselves. The experiments also indicate that the creatures aren’t a great source of inspiration for helmets and other protective materials.

[Related: We have no idea how dangerous football really is]

Once caveat to the study: The calculations were meant to emulate a woodpecker’s normal activities, but don’t address what might happen if the bird were to peck a metal pole or other unyielding material, Van Wassenbergh acknowledges. The researchers are now studying how beak shape optimizes pecking performance, and how woodpeckers manage to dislodge their beaks when they get stuck. 

The data are “pretty convincing,” says John Bates, a curator of birds at the Field Museum of Natural History in Chicago, but don’t rule out the possibility that routine pecking could give rise to some brain damage over time. Researchers have previously reported that deceased woodpeckers had protein buildups in their skulls similar to those seen in humans with neurodegenerative diseases and chronic brain injury. It’s unclear if the proteins are actually a sign of brain damage in woodpeckers like the way they are in people, though. 

Another question for future research is whether the new findings translate to other avian groups, Bates says. His team studies kingfishers, which can dive straight down into the water at speeds of up to 25 miles per hour. “Woodpeckers are definitely pretty unique,” he says, “but they’re not the only things that do some hammering.”

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In 2020 and 2021, COVID-19 became the third leading cause of death in the US. This May, the country passed the grim milestone of 1 million known COVID deaths. Although fewer people are dying from the virus now than during the height of the Omicron surge this winter or previous waves, new strains have continued to take lives.

As the pandemic drags on, understanding how many people are dying and who is most vulnerable remains crucial for efforts to avert further deaths. To that end, the Centers for Disease Control and Prevention (CDC) recently updated the software it uses to process all of the country’s mortality data. The change, powered by advanced computing techniques like machine learning, could supply health officials and the public with more up-to-date information about the disease. 

“Civil registration of births and deaths and understanding causes of death are really key to a functioning health system,” says Emily Smith, an assistant professor of global health at George Washington University. “There are a lot of ways to use this information.” 

Tracking the leading causes of death in a community and identifying where those deaths are concentrated helps public health officials direct resources, she adds. During a crisis like the COVID pandemic, having prompt information is particularly crucial. But the national statistics system has been slow to process and post mortality figures. When the US passed a million deaths from the virus earlier this year, the CDC’s tracker was still weeks behind.

“Effective epidemic response is getting the right resources—whether that’s drugs or vaccines or prevention programs—to the right people at the right time,” Smith says. “Data helps us do that.” 

The CDC upgrade represents an important step forward. “It’s great to see the US moving ahead with this,” Smith notes. “More transparent, faster data is a great advance.”

Coding COVID-19

For decades, the CDC has relied on computers to analyze death certificates and assign four-digit codes to each report based on the underlying cause so they can be tracked by the National Vital Statistics System. 

However, only about 70 to 75 percent of the country’s death certificates could be coded automatically; the rest were flagged for review, which means a staff member would have to input the cause of death into the system by hand. “When you’re dealing with 2 to 3 million deaths [every year], 25 to 30 percent of records is quite a substantial number and requires quite a lot of resources,” says Robert Anderson, chief of the Mortality Statistics Branch at the National Center for Health Statistics.

The updated cause of death coding system, known as MedCoder, can handle a greater proportion of these records: It currently codes 85 percent of records automatically, and with continued improvements, “has the potential to code better than 90 percent of records,” Anderson says. “These records can be autocoded in minutes, whereas manual review might take a couple of weeks,” he adds. “It just means more information is available in a more timely fashion.”

MedCoder is more adept than past systems at dealing with variations in the terms that physicians, medical examiners, and coroners use to describe mortalities, Anderson explains.  The computer assigns one of 10,000 possible codes for causes of death to a record. For example, when COVID is mentioned on a death certificate, it chooses U07.1. To improve the results, Anderson and his team used machine learning techniques that drew upon a decade’s worth of national death certificate data to train MedCoder to recognize mistakes and other aberrations. So, when a doctor fills out the death certificate with “Coronavirus 2019,” “SARS-CoV-2,” “Delta variant,” or another name for the disease, the computer still codes it as U07.1. “The old system would say, ‘I don’t find that term in the dictionary,’ and kick it out for somebody to look at,” Anderson explains. “[Now] the computer says, ‘Okay, I know what to do with this and what code to assign.”

[Related: AI confirms the pandemic bummed people out]

While installing the upgrades between June 6 to 24, the National Center for Health Statistics paused its processing of death data reported by states and didn’t refresh the COVID surveillance datasets on the National Vital Statistics System’s public page. Counts from weeks earlier in 2022 may temporarily seem low while the system catches up and reprocesses these records, the agency’s website notes. 

“Once we get over this backlog here the system is going to function pretty much the way the old system did,” Anderson says. “I don’t want people to worry that the data that we’re putting out now is not comparable to the data we were putting out before. It is comparable; it’s just going to be a little more timely.”

Mortality numbers matter

It’s unusual for death certificates to mention which variant of SARS-CoV-2 afflicted the deceased person. But looking for patterns in more precise mortality data can help health experts understand how dangerous a new strain might be—and whether extra precautions are needed.

“If deaths are rising it increases the urgency,” Anderson says. “If the data aren’t as timely, then our situational awareness degrades by a week or two or maybe three.” 

[Related: Omicron variants keep getting better at dodging our immune systems]

It’s also possible that having speedier data would have allowed the US to recognize that it had reached 1 million COVID-19 deaths sooner. “Having better real-time data hypothetically should matter on a lot of different fronts,” Smith says. “It matters for public perception; it matters for political will.”

Reported deaths tend to lag behind other warning signs such as a rise in positive COVID tests or hospitalizations. However, these measures can be difficult to interpret. An uptick in hospitalizations can indicate that more people are becoming seriously ill, but might not capture the full scope of the problem because not everybody with severe disease has access to hospitals.

“Those are softer outcomes that incorporate both the severity of the disease and other social and economic factors, whereas death is a hard outcome.” Smith says. “Mortality is the ultimate indicator—it’s black and white.”

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Since the emergence of COVID-19, sleep troubles have been on the rise. One way that people have been coping with pandemic-induced stress is by taking melatonin to help them slumber. 

However, experts caution that melatonin probably isn’t a good option for long-term insomnia. In very rare cases, the hormone can make children sick if they ingest too much. 

“It’s important, especially in kids, not to use melatonin until you’ve spoken with your pediatrician or your sleep doctor,” says M. Adeel Rishi, a pulmonology, sleep medicine, and critical care specialist in Indiana and vice chair of the American Academy of Sleep Medicine Public Safety Committee.

If you do decide to take melatonin, here are a few things to keep in mind.

Melatonin is a short-term fix

Melatonin is a naturally occurring hormone found in all mammals that controls the sleep-wake cycle. It’s produced by the pineal gland in the brain and also helps regulate the “ebb and flow” of our body temperature and blood sugar, Rishi says.

Melatonin can be used to treat circadian rhythm problems such as jetlag. Short-term use of melatonin “appears to be safe for most people,” according to the National Center for Complementary and Integrative Health at the National Institutes of Health. 

“In a situation where you have acute insomnia—all of a sudden having difficulty sleeping—I think for adult patients up to 5 milligrams of melatonin is probably appropriate for a few days,” Rishi says. (Timing recommendations can vary from 30 to 90 minutes before bed, but never right before.) If you experience side effects such as excessive sleepiness or dizziness, stop taking melatonin and check in with your doctor, he advises.

[Related: A good night’s sleep can boost cardiac health]

There’s limited evidence that melatonin is effective for chronic insomnia, and it’s unknown whether taking the hormone over extended periods could have any health consequences. 

“We have better options than melatonin when treating patients with chronic insomnia,” Rishi says. “The Academy recommends using cognitive behavioral therapy as the first-line approach for most patients…once it’s done the right way, the effects are longer-lasting than pharmacological approaches.”

It’s very rare for children to become seriously ill from taking too much melatonin, says Katharina Graw-Panzer, a pediatric sleep medicine expert at Weill Cornell Medicine and NewYork-Presbyterian Hospital. However, there isn’t data on whether melatonin could have any effects on children’s development over time. 

With a pediatrician’s supervision, children can take the hormone at very low doses and for brief periods to help regulate their sleep schedules, Graw-Panzer says. But it shouldn’t be the first option parents try. “Before we start melatonin, most importantly we have to work on good sleep habits in children, or sleep hygiene,” she says. 

Supplements get limited oversight

Because melatonin is categorized as a dietary supplement in the states, it doesn’t have the same rigorous oversight that prescription or over-the-counter medications receive from the US Food and Drug Administration (FDA).

This means that the actual amount of melatonin might not match what the bottle claims. A 2017 study in the Journal of Clinical Sleep Medicine found that the concentration of melatonin in commercial supplements ranged from 83 to 478 percent of the labeled content. Furthermore, eight of the 30 supplements were contaminated with serotonin—another naturally occurring compound that is targeted by some antidepressants, and which shouldn’t be taken without a doctor’s guidance, Rishi says.

The lack of regulation for melatonin makes it difficult for researchers to study its potential long-term impacts. “Whatever data we have available is hard to compare head-to-head, because you really don’t know what they were using in the study: how much it was, whether there was an impurity,” Rishi says. 

However, he adds, there is a way to check whether a melatonin supplement has a dosage that reflects what’s marked on the bottle: Look for a USP label. Products that bear this label must meet standards for key attributes such as potency and purity established by the nonprofit United States Pharmacopeia.

Kids are getting sick from melatonin

As melatonin has become more widely available and popular over the past decade, there has been a dramatic rise in cases of children unintentionally swallowing melatonin. 

The annual number of pediatric melatonin ingestions reported to poison control centers increased by 530 percent from 2012 to 2021 for a total of 260,435 cases, indicates a study released last month by the Centers for Disease Control and Prevention (CDC). About 84 percent of the children experienced no symptoms, but 287 required intensive care and five needed to be put on mechanical ventilators. Two young children, aged three months and 13 months, died in their homes.

“The dose recommended in children is significantly lower than what is recommended in adults, and if you take too much of anything you have an overdose,” Rishi says. “Although it’s come to attention really in the last couple of years, we know that cases of melatonin among children have been on an upswing even before the pandemic.”

Signs of a melatonin overdose may include nausea and vomiting, low blood pressure, lethargy, excessive sleepiness, dizziness, and confusion, he says.

[Related: How to get your kids on a healthy sleep schedule] 

The largest annual increase in pediatric melatonin ingestions coincided with the beginning of the COVID-19 pandemic, the CDC noted. This might be because melatonin use increased among stressed-out adults, and children were spending more time at home–in closer proximity to the supplements–due to school closures.

As a largely unregulated supplement, melatonin often is sold in bottles without child safety caps and comes in formulations such as gummy bears that kids find particularly appealing. Furthermore, adults may not be as safety-conscious of a product sold as a supplement rather than a medication, Rishi says.

“You put all of that together and it’s not hard to see why we are seeing these reports” of melatonin ingestion, he says. “It’s this perfect storm that we’re in.” 

For melatonin to be used safely, Rishi says, “it all starts with changing how it’s marketed.” Ideally, he says, melatonin would fall under the same rigorous scrutiny that the FDA gives other medicines. “Through that hopefully the public perception of melatonin will change somewhat and people will start regarding it as a medication and will be more safety conscious.”

Graw-Panzer emphasizes that melatonin should be stored out of reach of children.

“What is important to always remember is that melatonin,” she says, “even if it’s over the counter, is still a medication.”

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In the wake of the Supreme Court’s decision last month to strike down Roe v. Wade and end the constitutional right to abortion, demand for emergency contraceptives has increased in many areas. Some people have been swift to stock up on morning-after pills out of concern they won’t be able to access an abortion, or because they fear possible future restrictions on birth control, as the New York Times recently reported.

Emergency contraceptives, which prevent a pregnancy from happening in the first place, are different from abortion pills. However, it’s useful to understand how both kinds of medicines work and when they’re used, experts say, especially as demand surges. Reproductive health company Stix told the New York Times sales of its morning-after pill rose 600 percent within a day of the Supreme Court ruling.  

“A lot of confusion around emergency contraception and how it works is probably due to the fact that we do such a poor job of teaching reproductive health,” says Beverly Gray, an OB-GYN with Duke Health in North Carolina and founder of the Duke Reproductive Health Equity and Advocacy Mobilization team. “[Our] patients are experts in their own lives, as far as what methods of contraception are going to work for them.”

Emergency contraceptives can be taken up to five days after unprotected sex, the length of time that sperm can live in the reproductive tract. They delay or prevent ovulation, the step in the menstrual cycle in which an egg is released from an ovary, which in turn stops the fusion of sperm and egg. 

“If the egg is released a few days later or not at all during that cycle, then the sperm and the egg cannot unite,” Gray says.

[Related: Why doctors still don’t understand the side effects of hormonal birth control]

Emergency contraceptives don’t work once a fertilized egg has implanted in the uterus. In other words, they don’t disrupt ongoing pregnancies, Gray says.

Some morning-after pills contain levonorgestrel, which belongs to a group of drugs called progestins that mimic the naturally-occurring hormone progesterone. Plan B One-Step, which has a shelf life of about four years, is an example of a levonorgestrel-based pill. This compound is also used in lower doses for some other forms of contraception, Aldene Zeno, an OB-GYN with Keck Medicine of University of Southern California, writes in an email. 

Levonorgestrel suppresses the surge of luteinizing hormone that typically triggers ovulation. Additionally, the drug thickens mucus in the reproductive tract to make it difficult for the sperm and egg to travel to each other and changes the lining of the uterus to prevent implantation if the sperm and egg do meet.

“Biologically we as humans are wired to carry one pregnancy at a time. That pregnancy may be a singleton or multiples like twins, but either way once someone becomes pregnant their body triggers processes, many driven by progesterone, to prevent another pregnancy from happening,” Zeno says. “Plan B mimics this mechanism of preventing pregnancy, however, it is not effective for terminating an existing pregnancy.”

One advantage of levonorgestrel-based emergency contraceptives is that they’re available without a prescription. However, they don’t work as well in people who weigh more than 165 pounds. The sooner the pills are taken after unprotected sex—ideally within 72 hours—the more effective they are, lowering chances of pregnancy by 75 to 89 percent.

Another kind of emergency contraceptive pill is ulipristal, which is sold under the brand name Ella. It’s more effective than levonorgestrel-based pills and can be taken up to five days after unprotected sex. If taken in that window, it reduces chances of pregnancy by 85 percent, according to Planned Parenthood. However, ulipristal may not work as well in people over 195 pounds and is only available by prescription. 

In addition to blocking the luteinizing hormone surge, ulipristal can also disrupt ovulation later in a person’s menstrual cycle by preventing the follicles—fluid-filled sacs in the ovaries that contain eggs—from rupturing. Compared with levonorgestrel-based pills, Gray says, “it works a little better if you’re right around the time of ovulation, if the luteinizing hormone surge is already happening.” 

Another option for emergency contraception that’s even more effective is to get a copper IUD implanted within five days of unprotected sex, Gray says. If inserted within that time frame, IUDs reduce pregnancy chances by 99.9 percent. Copper has spermicidal properties and may also prevent implantation, but doesn’t disrupt an already established pregnancy. It also works regardless of a person’s weight. Hormonal IUDs that release levonorgestrel such as Mirena can also be used for emergency contraception. A study published last year in the New England Journal of Medicine indicates that levonorgestrel-releasing hormonal IUDs are equivalent in effectiveness to the copper IUD for emergency contraception. 

While emergency contraceptives prevent pregnancy, abortion pills are used to end an existing one. A medication abortion can be done up to around 11 weeks into pregnancy and requires taking two drugs. The first pill, called mifepristone, blocks the hormone progesterone, which is necessary for the pregnancy to grow. The second medicine, misoprostol, causes cramping and bleeding to help the uterus empty itself. These medications are also used to treat miscarriages. 

“All birth control methods have failure rates, including emergency contraception,” Zeno says. This is one reason why abortion will remain an important backstop. “Abortion care is an integral aspect of women’s health care.” 

[Related: What science tells us about abortion bans]

Since the Supreme Court decision, Gray and her colleagues have seen requests for long-acting forms of contraception shoot up. “We’re seeing just a higher volume than we’ve ever seen,” she says. For people who aren’t already using a highly effective form of contraception such as an IUD, though, it’s not a bad idea to have morning-after pills on hand. “I think it’s good to be prepared,” Gray says. 

Still, Zeno advises against stockpiling emergency contraception in response to the ruling.

“There are concerns with regards to equity when it comes to ‘morning after pill’ access,” she said, noting that emergency contraception is less readily available in low-income and predominantly Latinx and Black neighborhoods. “If those with means buy most of the supply in their area, they are disenfranchising those who may otherwise need it and already have limited resources.”

Ensuring that birth control is widely available leads to fewer unintended pregnancies and abortions, she added. “Access to emergency contraception is important,” Zeno said. “However, instead of stocking up on emergency contraception I advocate for long-acting, reversible contraception methods.” These include the IUD and implants such as Nexplanon. 

To help determine which contraceptive method will work best for you, Gray recommends checking out the birth control support network Bedsider and the American College of Obstetricians and Gynecologists website.

The post What’s the difference between morning-after pills and abortion medications? appeared first on Popular Science.

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Dengue and Zika viruses manipulate skin-dwelling bacteria to make their mammalian hosts smell more attractive to mosquitoes, a new study indicates. It’s the first hard evidence of viruses using scented subterfuge to accelerate their spread.

Disease experts used a series of experiments to determine that “skeeters” prefer to dine on a small group of mice infected with dengue and Zika. These infections caused the bacterial communities on the animals’ skin to boost production of a molecule called acetophenone, which in turn piqued the interest of mosquitoes. However, giving the rodents a chemical derived from vitamin A–that also happens to be a medication for severe acne–countered the effect after several days.

Treating dengue and Zika patients with the compound could ward off mosquitoes and cut down on transmission of both diseases, the team reported today in the journal Cell.

The team was “very excited to find this interesting phenomenon, and offer a novel strategy to interrupt [the virus] lifecycle, thus controlling [them from] naturally spreading,” Gong Cheng, a microbiologist at Tsinghua University in China and coauthor of the findings, wrote in an email. “Our study may provide some novel [concepts] to inform real-world public health strategies.” 

[Related: Climate change could introduce humans to thousands of new viruses]

Previous studies have reported that mosquitoes are drawn to the scent of people infected with the malaria parasite. Infectious disease scientists have strongly suspected that this is also the case for certain viruses spread by insects and other arthropods. But this is the first time that researchers have actually identified a molecule that can prompt the attraction, Rollie Clem, a virologist at Kansas State University who wasn’t involved in the research, said in an email.

“This is very elegant and important science. Virologists are realizing more and more that we need to take into account not only the direct interactions between viruses and their hosts, but also with the other microorganisms that are present in or on the host,” he explained. “All of the living things that we as humans generally think about, whether they are animals or plants, are not single entities, but are communities of organisms.” 

Zika virus is spread by infected mosquitoes in tropical and subtropical regions. It usually causes mild or no symptoms, but infection during pregnancy can lead to microcephaly and other congenital problems. Dengue also occurs in tropical and subtropical climates and causes an estimated 100 to 400 million infections each year, although most are not severe. 

To understand how the viruses might use odor to aid their own transmission, Cheng and his team first demonstrated that when given the choice between infected and healthy mice, more mosquitoes tried to feed on the sick rodents. The researchers then filtered out chemicals known as volatiles from the air around the rodents to mute the scent of their infections. Without that cue, mosquitoes downwind of the mice went after healthy animals just as often as sick ones.

The researchers next analyzed the chemical composition of the volatiles, and identified 20 compounds that increased or decreased in both dengue- and Zika-infected mice. The team used a technique called electroantennography, which measures electrical signals being sent from an insect’s antennae to the brain, to assess the mosquitoes’ interest in the different chemicals. They saw that acetophenone, a common byproduct from skin bacteria that’s also used as a fragrance and flavoring agent, prompted the strongest physiological response in the blood suckers. 

To test this further, Cheng and his colleagues set up side experiments involving the compound. They found that mosquitoes were more drawn to chambers filled with acetophenone than empty ones. The insects were also significantly more interested in mice with acetophenone sprinkled on their skin, and to humans with acetophenone rubbed on their hands, than those without. Additionally, mosquitoes were eager to feed on human volunteers with filter paper laced with volatiles attached to their palms. (The non-infectious samples were swabbed from the armpits of dengue patients.)

Separately, the researchers discovered that mice infected with dengue and Zika produced 10 times more acetophenone than uninfected ones. Human dengue patients produced more acetophenone than healthy subjects, too, but the exact difference was not measured.

Finally, to confirm the origins of the tip-off scent, the team used an alcohol spray to remove the skin microbiota from infected and uninfected mice. That caused the rodents to hardly produce any acetophenone.

While several types of bacteria were more plentiful on the skin of infected mice than healthy ones, four species of Bacillus bacteria notably registered as “potent producers” of acetophenone, the researchers wrote. When they spread those four species on healthy mice, the rodents drew more mosquitoes compared to others treated with the non-acetophenone-producing bacteria.

One way animals typically keep their skin bacterial populations in check and ward off disease-causing microbes is by secreting antimicrobial proteins. Cheng and his colleagues found evidence that dengue and Zika viruses block production of such proteins. Sick mice had reduced amounts of an antimicrobial protein called RELMα on their fur, as well as reductions in genetic material related to the protein. 

All of this indicates that by suppressing RELMα, the viruses encourage Bacillus bacteria to multiply and pump out more acetophenone, ultimately making the host more appealing to hungry mosquitoes.

Fortunately, Cheng and his team had a potential remedy in mind. Earlier research has indicated that rodents produce more RELMα and are more resistant to skin infections after eating compounds derived from vitamin A. The group fed infected mice a vitamin A derivative known as isotretinoin, which can be found in acne medication. After treatment, the rodents had significantly more RELMα protein and less Bacillus bacteria on their skin. That change did not make them mosquito-proof, however: They attracted a similar number of insects as the healthy mice, but fewer than the untreated infected ones.

[Related: 8 ways to repel insects without bug spray]

The study’s major limitation is that the majority of the results come from experiments in mice, which have different skin physiology than humans, Cheng wrote in his email. It’s possible that dengue and Zika could take advantage of different, unidentified bacteria when they infect humans, so further studies about how the viruses affect the skin microbial community and acetophenone production in humans are needed.

This summer, Cheng’s team will investigate whether administering vitamin A derivatives to dengue patients will shield them from mosquito bites. They also plan to explore whether gene editing can be used to create mosquito populations that cannot smell acetophenone, and therefore, wouldn’t make a beeline for virus-infected people. 

Another question for future research is whether other kinds of insect-borne viruses use similar tricks to turn their hosts into mosquito magnets, Clem said in his email. 

“People shouldn’t conclude, based on this study, that taking vitamin A will make them less attractive to mosquitoes,” he added. “It will only make the infected people look like normal, uninfected people to a mosquito.” In other words, the compound would keep sick people from being bitten more, but it wouldn’t work as a prophylactic for healthy people. 

Still, Clem said, the findings raise hope for limiting dengue and Zika transmission in parts of the world where these viruses are common. With close to half of the world’s population is at risk of being infected, even a tiny breakthrough could have important outcomes.

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Roughly 30,000 to 15,000 years ago, the first dogs emerged from gray wolves. Exactly when, where, and how this monumental event occurred isn’t known. For decades, geneticists and evolutionary biologists have been unable to come to a consensus on the long-standing mystery. However, a study published on June 29 in Nature may help narrow down the origins of our canine companions.

An international group of collaborators analyzed 72 genomes of ancient wolves from Europe, Siberia, and North America and compared them with modern wolves, as well as modern and ancient dogs. They determined that dogs are overall more genetically similar to ancient wolves from eastern Eurasia than those from western Eurasia. Additionally, the researchers found that ancient wolf populations remained closely related throughout much of the last 100,000 years and identified several mutations that may have helped the species weather the Ice Age.

“Overall, I found the study very exciting,” Benjamin N. Sacks, an evolutionary biologist at UC Davis who wasn’t involved in the research, said in an email. “The impressive chronology of ancient DNA samples from wolves provided an unprecedented window into the past.” 

For their analysis, the researchers extracted DNA from the bones of 66 ancient wolves and sequenced their genomes. The team compared this genetic material with a handful of previously reported ancient wolf genomes, as well as data from 68 modern wolves, 369 modern and 33 ancient dogs, and several other members of the dog family. 

On the whole, dogs were more closely related to ancient wolves from Asia than from Europe, says Anders Bergström, a geneticist at the Francis Crick Institute in London who co-authored the paper. But, he adds, “We also find that it gets a little more complex.” 

Dogs from Siberia, the Americas, East Asia, and northeastern Europe primarily stem from wolves somewhere in eastern Eurasia. “That source [of ancestry] is present in all dogs, and it peaks in its largest amounts in dogs from Siberia and also China and Australia,” Bergström says, naming the Siberian husky and Australia’s dingo as examples of dogs with the most genetic overlap with eastern Eurasian wolves. Meanwhile, dogs from the Near East in Asia and Africa—such as the basenji, Afghan hound, and saluki—derive up to half their ancestry from a population related to modern southwest Eurasian wolves. 

[Related: Did humans truly domesticate dogs? Canine history is more of a mystery than you think.]

The results indicate that at least two different ancient wolf populations contributed DNA to dogs, Bergström says. One explanation is that dogs were domesticated from wolves in two separate regions, then met and bred later on. “But it’s also possible that domestication happened just once, and as dogs arrived from the east they mixed with the local wild wolves,” Bergström says. “We can see very clearly this dual ancestry, but we cannot yet say whether this represents more than one domestication.”

None of the ancient wolf genomes represent an immediate ancestor of early dogs. In the future, the researchers plan to examine genomes from more locations in hopes of pinpointing where dogs first emerged.

“While we do make some progress on where dogs fit into the wolf puzzle, we still haven’t solved the question of dog origins,” Bergström says. “The range of possibilities for where dogs came from is still quite large.” 

He and his colleagues were also surprised to observe that distant wolf populations remained genetically similar to each other throughout the Late Pleistocene, which ended about 11,700 years ago. “We think this reflects a high degree of mobility of wolves in the Ice Age, and perhaps this is part of what allowed them to survive when many other animals disappeared,” Bergström says. “They were able to avoid getting fragmented into small isolated groups.”

[Related: Dogs know exactly what they’re doing when they give you the ‘puppy eyes’]

Additionally, the researchers identified several mutations that arose during the last 100,000 years and rapidly spread through the wolf gene pool. Some of these mutations appeared on a gene known as IFT88 between 40,000 and 30,000 years ago. In humans and mice, this gene is involved in the development of the cranium and mandible. It’s possible that the mutations made ancient wolves evolve jaws that helped them become more effective hunters or allowed them to pursue new sources of prey. 

“We think this dramatic example of natural selection could reflect how wolves adapted…during the changing climate of the Ice Age,” Bergström says. He and his team also identified mutations on genes that play a role in olfaction, hinting that wolves may have improved their sense of smell during the Ice Age. 

Many questions about the evolutionary history of wolves remain, Sacks noted. Ancient wolves from North America were more genetically distinct than other populations, perhaps as a result of mingling with coyotes. Understanding when this interbreeding occurred has “important implications” for demystifying the evolution of red and timber wolves in North America, Sacks said.

However, he added, the paper’s evidence for two sources of wolf ancestry in modern dogs fits genetic differences Sacks and his collaborators have independently observed in dogs from different parts of Asia and Australia. 

“As the authors point out, however, there are still holes in need of filling before the story of dog origins is fully understood,” Sacks concluded.

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The Supreme Court of the US has ruled to overturn Roe v. Wade, dismantling Americans’ constitutional right to an abortion. 

The case, Dobbs v. Jackson Women’s Health Organization, concerns a 2018 law passed by Mississippi barring abortions after 15 weeks of pregnancy. The Supreme Court’s decision, released this morning, was similar to a draft opinion leaked to Politico in early May. In their dissenting opinion, Justices Stephen Breyer, Sonia Sotomayor, and Elena Kagan wrote, “Yesterday, the Constitution guaranteed that a woman confronted with an unplanned pregnancy could (within reasonable limits) make her own decision about whether to bear a child, with all the life-transforming consequences that act involves … But no longer. As of today, this court holds, a state can always force a woman to give birth, prohibiting even the earliest abortions.”

US Attorney General Merrick Garland described the decision as a “devastating blow” and said that the Justice Department would use “every tool at [its] disposal” to protect reproductive freedom. 

The fallout of the ruling will vary greatly from one state to the next, and some restrictions will take effect sooner than others. About half of US states are expected to ban abortion. Thirteen states have “trigger” laws in place that were intended to illegalize relevant medications and procedures in the event that Roe v. Wade was demolished, some of which could go into effect right away. Other states have introduced legislation to safeguard abortion access.  

“Access to healthcare should not be determined by what state we live in,” says Aileen Gariepy, an OB-GYN and director of complex family planning at Weill Cornell Medicine in New York. “In New York, the right is protected, the healthcare is protected. But for people living in half of the states, they won’t have that same autonomy and dignity.”

Many pregnant people don’t have the resources to travel to neighboring states to receive abortion care. “Women with less financial resources and unstable housing, lack of transportation, living in rural communities or in poverty, will be the ones that are most affected,” Gariepy says.

[Related: Miscarriages could become more dangerous in a post-Roe world]

In the past few years, hundreds of thousands of Americans of a wide range of ages, religions, ethnicities, and economic backgrounds have received abortions at clinics and doctor’s offices. Blocking access to abortion will only serve to increase health complications and deaths among pregnant people, Gariepy explains, compounding the nation’s already-terrible record with maternal fatalities. She also foresees that abortion bans will spill over to impact other aspects of healthcare, such as treatment for miscarriages and infertility. 

“These abortion bans don’t solve any problems,” says Angela Y. Chen, an OBGYN and director of the family planning division at UCLA Health. Abortion restrictions have mounted in recent years across much of the country, and have already demonstrated that barriers to reproductive healthcare only create unnecessary delays and harm for pregnant people, she says.

“Abortion care is very safe,” Chen emphasizes. Most abortions take place during the first trimester, either through medication or an in-clinic procedure. 

“I have great concern for women who develop the need for abortion later in pregnancy,” Chen says. “They will have to leave their home and their providers to seek care elsewhere when they are feeling the most vulnerable. Their situations may have changed: It could be a new diagnosis of a fetal problem, or onset of a maternal condition that makes continuation of pregnancy dangerous.” 

“As you progress further into the pregnancy, the medical risks start to increase,” she adds. “We don’t want to add any further delay for any woman who needs to get their care quickly.”

The Supreme Court decision raises a host of thorny legal issues for pregnant people, healthcare providers, and state governments, says Khiara M. Bridges, a professor at the UC Berkeley School of Law, who specializes in race, class, and reproductive rights. 

“We are going to see an abundance of lawsuits for the next 10 years, if not longer, around what states can and cannot do to regulate abortion,” she says. “It’s complicated. There aren’t easy answers, and there’s a lot of uncertainty.”

“In states with existing trigger laws [that ban abortion], there’s uncertainty about whether they’re in effect or not,” Bridges explains further. “Providers likely would not provide abortions because of the uncertainty, because they might be subject to criminal punishment. So in those states, I imagine there will not be abortions being performed immediately after Roe falls … but I’m not sure that’s how providers will organize their lives.”

Physicians in states facing harsh new restrictions on abortion are already confronting difficult questions about how best to provide care to their patients. Some are still continuing to deliver care and resources, while others are gearing up to face legal pushback.

“I’m thinking now about what can we do to get more people in for birth control and IUDs, and expedite people getting those services because they’re so much more important than they’ve ever been before,” Louis Monnig, an OBGYN in Louisville, Kentucky, told the New York Times. “How can we streamline mutual aid and abortion assistance to patients who will likely need to travel and incur more expenses and loss of time at work just to exercise their bodily autonomy?”

It’s probably that more people will obtain abortion pills without a prescription or doctor’s supervision. A number of organizations such as Plan C offer information about how people can self-manage abortions. 

“Self-managed abortion can be safe when people have access to [the medications] mifepristone and misoprostol,” Gariepy says. “Healthcare organizations and physicians will be working towards making sure that that is clear, versus traditional or historic or other kind of mythical self-managed abortion [methods] like drinking turpentine or inserting knitting needles.”

[Related: The dangers of digital health monitoring after abortion bans]

Additionally, areas where abortion care is protected are planning for a surge of people from those with more restrictive rules. “States like Colorado, Minnesota, [and] Illinois are probably going to see a surge, more so even than New York,” which is in a region with more abortion protections, Gariepy says. “But certainly doctors are trying to meet people where they’re at. Women coming to us for safe compassionate abortion care will get it.” 

Medical associations were swift to condemn the Supreme Court ruling as well. “Allowing states to set individual restrictive abortion policies, including restrictions outright bans on this essential component of medical care, results in increased inequities that already plague the healthcare system and this country,” the American College of Obstetricians and Gynecologists said in a statement.

In its statement, the American Medical Association described the decision as an “egregious allowance of government intrusion into medicine.”

“We will always have physicians’ backs and defend the practice of medicine, we will fight to protect the patient-physician relationship, and we will oppose any law or regulation that compromises or criminalizes patient access to safe, evidence-based medical care, including abortion,” the organization wrote. “As the health of millions of patients hangs in the balance, this is a fight we will not give up.”

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When it comes to longevity, scientists have long suspected that scaly and slimy vertebrates have an edge. Galápagos tortoises, eastern box turtles, cave-dwelling salamanders known as olms, and a number of other reptiles and amphibians can live more than a century. And the oldest known land animal, a Seychelles giant tortoise named Jonathan, recently celebrated his 190th birthday. 

Until now, though, most of the evidence highlighting the long lifespans of these animals have come from anecdotal reports from zoos, says Beth Reinke, a biologist at Northeastern Illinois University in Chicago. She and a team of more than 100 researchers from around the globe have compared rates of aging in 77 species of reptiles and amphibians in the wild. The study initially grew out of the long-running notion that turtles can live for a long time. “We wanted to know how widespread that is,” Reinke says.

The researchers found that although aging and lifespan varied greatly from one species to the next, turtles, crocodilians, and salamanders generally aged very slowly and had disproportionately long lifespans for their size. Meanwhile, another group of researchers in Denmark reached similar conclusions after comparing 52 species of turtles and tortoises living in zoos and aquariums: roughly 75 percent of the reptiles showed slow or negligible senescence, and 80 percent aged more slowly than modern humans. 

Both teams reported their results on June 23 in Science. The new findings aren’t particularly surprising but do challenge the idea that senescence—a gradual decline in bodily functions that increases the mortality risk after an organism reaches sexual maturity—is universal, says Rob Salguero-Gómez, an ecologist at the University of Oxford who wasn’t involved in the research.

“They’re both excellent pieces of research,” he says. “They add a new layer…upon our understanding of senescence across the tree of life.” 

For their analysis, Reinke and her collaborators drew from long-running studies on a wide variety of animals that included turtles, frogs, salamanders, crocodilians, snakes, lizards, and the lizard-like tuatara. These studies tracked reptile and amphibian populations over an average period of 17 years and encompassed more than 190,000 individual animals.

To determine how quickly a species aged, Reinke and her team calculated the rate at which its individual members died over time after hitting sexual maturity. The team estimated lifespan  from the number of years it took for 95 percent of these adult animals to die. 

One caveat to these estimates, Reinke notes, is that the researchers didn’t distinguish between different causes of death. “When people hear ‘aging,’ they tend to think of just physiology,” she says. “Our measure of aging includes not just physiology, but all things that could cause death in the wild.” 

[Related: These jellyfish seem to cheat death. What’s their secret?]

The team also compared their estimates with previously published data on aging in mammals and birds. These groups of vertebrates are warm-blooded or endothermic, meaning they are capable of regulating their own body temperature. Reinke and her team expected to find that the cold-blooded, or ectothermic, reptiles and amphibians would age more slowly on the whole than birds and mammals because their slower metabolisms put less physiological wear and tear on their bodies. But the results revealed a mixed bag. While some reptiles and amphibians did age more slowly than most birds and mammals, others aged faster. Longevity in reptiles and amphibians varied from 1 to 137 years—a much wider range than the 4 to 84 years seen in primates. 

However, species with negligible aging appeared across the reptile and amphibian family tree, and turtles as a group were “uniquely slow agers,” she says.

Species equipped with protective shells, scaly armor, or venom aged more slowly and lived longer. In both reptiles and amphibians, species that began reproducing later in life ended up living longer. The team also observed that reptiles that lived in warm temperatures aged more quickly, while amphibians in similar conditions aged more slowly.  

More research is needed to tease out how these and other variables drive differences in aging and longevity. “There are a lot of really interesting patterns that we brought to light that need to be explored further,” Reinke says. “I think that ectotherms could have the answers to a lot of what we want to know about aging for human health.”

In the quest to extend human life, salamanders may be a particularly promising group to focus on. “A lot of them can live for 10 years or more, which for their size is a lot,” Reinke says. These amphibians are famous for their ability to regrow lost limbs and tails, leading some scientists to believe that there may be a connection between these regenerative capabilities and the salamanders’ impressive longevity.

For the second new paper, the team out of Denmark focused on aging in captive reptiles.

“All these theories of senescence state that…the risk of mortality would increase with age after sexuality maturity, when we stop putting so much energy into repairing cell damage and tissues and put more energy into reproduction,” says Rita da Silva, a biologist at the University of Southern Denmark in Odense and coauthor of the findings. 

The best candidates for a species that might escape the damaging effects of getting old are those that continue growing their entire lives, such as turtles and tortoises. 

“What we were mainly interested in is if their risk of mortality increases with age as it does in humans for instance, and in other mammals and in birds,” da Silva says. She and her colleagues analyzed records of captive turtles and tortoises, with data for each species ranging from 58 to several thousand individuals. 

In most species, mortality either remained constant with age or actually decreased.  On average, male turtles and tortoises lived longer than females—the opposite of what’s seen in mammals. For three of the species, the team also examined data on wild populations, and found that captive animals enjoyed lower rates of aging.

“In some way these populations found a way to lower their aging rates when the conditions are favorable,” da Silva says. In captivity, reptiles don’t need to pour energy into finding food or shelter. But it’s not clear why only some reptiles seem to respond to this bounty by minimizing or avoiding senescence. “For some other species either the conditions are not ideal or they are not really able to switch off the senescence,” da Silva speculates.

[Related: Has the fountain of youth been in our blood all along?]

While the majority of turtle and tortoise species studied aged more slowly than humans, it’s too soon to say what implications the findings could have for efforts to understand human health and aging. 

“We need to be careful when making these comparisons,” da Silva says. “We cannot draw a clear connection between this and humans, [but] I can say that we are one step closer to understanding the mechanisms of aging.”

The two new papers show how much remains to be discovered about aging and how it differs among humans and other animals, plants, and more distantly related organisms, Salguero-Gómez says.

“There’s true value in this type of research beyond the potential translations into biomedical research, just for a higher appreciation for our place in the tree of life and also for the realization that not everything follows a human way of living,” he says.

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A newly discovered subpopulation of polar bears in remote southeastern Greenland have found a way to eke out a living under warm conditions similar to those forecasted for much of the Arctic later this century, scientists reported on June 16 in Science.

Warming temperatures are causing sea ice, which polar bears depend upon for survival, to diminish. However, the hardy Southeast Greenland bears use freshwater ice from coastal glaciers as platforms from which to hunt seals year-round. These glaciers may create previously unrecognized “climate refugia” for polar bears, the researchers wrote.

“Our study lays out the evidence for a previously undocumented and highly isolated subpopulation of polar bears on the southeast coast of Greenland surviving in a special way,” Kristin L. Laidre, a marine biologist at the University of Washington in Seattle, said in an email. “These bears can perhaps tell us a bit more about the future for the species.”

Although the glacier ice allows the bears to inhabit fjords that are sea-ice-free for more than eight months of the year, this habitat is unusual for most of the Arctic. “Glacier ice may help small numbers of polar bears survive for longer periods under climate warming, and may be important to the species persistence (meaning preventing extinction), but it is not available for the vast majority of polar bears,” Laidre acknowledged. 

She and her collaborators identified the unique group while surveying polar bears along Greenland’s east coast, which is about 1,800 miles long. The team drew upon more than three decades of data from captured polar bears and samples collected from subsistence hunters. The researchers tracked the movements of bears wearing GPS collars as well as analyzing DNA and observing the demographics of polar bears in the region. 

To their surprise, the researchers realized that bears in Southeast Greenland did not interact with bears along the northern part of the coastline. They found that these southerly bears were genetically distinct from the 19 other previously recognized polar bear subpopulations. “They are the most genetically isolated polar bears in the world,” noted Laidre.

The researchers estimated that this subpopulation has been largely isolated for hundreds of years. One explanation is that the landscape is difficult to navigate, with steep fjords separating mountains and narrow glaciers. Meanwhile, the bears are penned in by the Greenland Ice Sheet to the west and the open water of the Denmark Strait to the east. The bears may also be cut off from their northern neighbors by the fast-flowing East Greenland Coastal Current. The rugged landscape and barricading terrain might have made it more difficult for the Southeast Greenland bears to find mates, resulting in fewer cubs born than other subpopulations.

[Related: For polar bears contending with climate change, it’s ‘survival of the fattest’]

Sea ice frozen to the shore, known as fast ice, typically persists from February to late May in this part of Greenland. This means that the bears are left without sea ice for more than 250 days of the year—over 100 days longer than they can go without feeding. 

Elsewhere in the Arctic, polar bears move to land or head northward when sea ice recedes during the warmer months. But the freshwater ice flowing into the sea from the Greenland Ice Sheet, known as glacial mélange, allowed the Southeast Greenland bears to stay put and capture prey throughout the year.

Some bears remained in the same fjord for years. On 11 occasions, the researchers observed polar bears carried southwards on drift ice caught in the East Greenland Coastal Current. All the bears swam ashore and trekked back to their home fjord within a month or two.

The researchers calculated that there are several hundred polar bears in Southeast Greenland. However, it’s unclear whether their numbers are growing, decreasing, or holding steady. “This is important to know and requires further monitoring,” Laidre said.

Conserving this subpopulation is vital to preserve the genetic diversity of the species and understand how polar bears will be affected by climate change, she and her colleagues concluded. While glacial mélanges aren’t common, they can be found in other parts of Greenland and the Norwegian archipelago of Svalbard and are inhabited by ring seals, the main prey of polar bears. It’s possible that such conditions may give bears beyond the Southeast Greenland subpopulation a buffer against dwindling sea ice.

However, “loss of Arctic sea ice is still the primary threat to all polar bears,” Laidre said. “This study does not change that.” Even the freshwater ice havens may be transformed as the Arctic heats up and the Greenland Ice Sheet melts.

“Climate action is the single most important thing for the future of polar bears,” Laidre said.

[Related: Record-breaking heat is bombarding the North and South poles]

Robert Newton, a geochemist at Columbia University’s ​Lamont-Doherty Earth Observatory who studies Arctic sea ice, praised the wealth of information that Laidre and her team analyzed to discover the new subpopulation. 

“The article itself is very hopeful in the sense that it does appear that the polar bears can survive without sea ice as long as they have some alternative platform from which to hunt,” he said, noting that it can take hundreds of years for glaciers to retreat. “It is quite possible that polar bears as a species will survive the loss of sea ice in the Arctic even if most of the populations are forced into extinction or forced onto land where they’ll merge back into the brown bear populations.” 

An important question for future studies is how well organisms further down the food chain, including seals, fish, crustaceans, and algae, will adapt in the face of shrinking sea ice, Newton added. Still, the findings indicate that glacial mélanges could offer a lifeline for polar bears until conditions stabilize.

“If we eventually do get greenhouse gasses and global warming under control and we’re able to return at some point to the historical temperatures at the surface of the Arctic, all of the modeling we’ve done indicates that the sea ice will return in short order,” he said. “If we can establish refugia and protect the animals there, we really are conserving something for the future.”

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More than six centuries ago, the Black Death ravaged Europe, Asia, and North Africa. The plague killed up to 60 percent of the people in western Eurasia within eight years. How the bacterial strain responsible for this pandemic infiltrated human populations has been debated ever since.

In a study published on June 15 in Nature, an international group of researchers pinpoints the Black Death’s ground zero to early 14th-century Central Asia. They analyzed historical records, archaeological data, and DNA from the teeth of skeletons buried in two cemeteries in Kyrgyzstan. Within those 700-year-old remains, the scientists identified the plague-causing bacterium, Yersinia pestis. 

The team concluded that the pandemic germ’s ancestor evolved in this area, based on its relationship to present-day strains of Y. pestis. The findings solve a centuries-old mystery and can also help understand emerging infectious diseases, Philip Slavin, a historian at the University of Stirling in Scotland and co-author of the findings, told Popular Science in an email. 

“It’s always important to not treat different strains as isolated phenomena,” he said, “but as something that is situated within a much wider evolutionary picture.”

Experts who weren’t involved with the study say the results are intriguing but require more confirmation.

“[The] findings are interesting but preliminary, and further research is desirable and required to enlarge and deepen the findings,” Ole J. Benedictow, an emeritus professor of archaeology, conservation, and history at the University of Oslo in Norway and author of The Complete History of the Black Death, said in an email. “Paleobiological historical plague studies are still in an early phase of development, we can expect a wealth of new interesting findings and many surprises in the future.” 

Finding plague in teeth

Infected fleas, whose rodent hosts have perished, typically transmit plague to people. Y. pestis has afflicted humans for more than a millenium, causing three separate pandemics that began in the 6th, 14th, and 19th centuries. The Black Death took place between 1346 and 1353; after this initial devastating wave, the bubonic plague settled into a pandemic that lasted for several centuries.

Scholars—including scientists from the 14th century and modern historians—have speculated about many potential locations for the Black Death’s initial source. Those sites have included China, Central Asia, the steppes between the Black and Caspian Seas, Mongolia, Russia, and India, Slavin said. 

To trace its origin, Slavin and his collaborators examined the remains from two cemeteries near Lake Issyk-Kul in present-day Kyrgyzstan. The cemeteries had been excavated during the late 19th century but are much older: Tombstone inscriptions dated from 1338 to 1339 state that a number of the bodies had been victims of “pestilence.” To verify the identity of that pestilence, the team extracted genetic material from the teeth (which preserve the pathogens present in a person’s bloodstream) of seven individuals. They detected Y. pestis in three people from the Kara-Djigach cemetery. 

While the DNA had broken down over time, two of the teeth contained enough material for the team to reconstruct the bacterial strain’s position within the plague family tree. The researchers concluded that the strain of Y. pestis in the teeth was the most recent common ancestor of several branches of plague still found today, one of which included the strain responsible for the Black Death. Additionally, the team reported, the ancient Kara-Djigach strain is closely related to the Y. pestis that continues to circulate in marmots of the surrounding Tian Shan mountains. 

“We consider [it] most probable that the ancient strain evolved locally, within the extended Tian Shan Mountain region, and was not introduced into the Kara-Djigach community from a far-away source,” Slavin said. “At some point the bacteria crossed over from marmots to humans.”

The presence of gems, silks, coins, and other artifacts near the cemeteries indicate that the communities struck by the epidemic contained many goods that had been produced far away. Trade may have played an important role spreading the pathogen westward to the Black Sea, Slavin said in a call with reporters. 

An unsettled genesis

The new report confirms that the pestilence victims near Lake Issyk-Kul did indeed die of plague, said Nükhet Varlık, a medical historian at Rutgers University–Newark who wasn’t involved in the research. However, this doesn’t necessarily establish the source of the Black Death. “Here we are presented with one plausible origins scenario, but it does not exclude other possible ones,” Varlık said in an email. 

Many questions remain concerning the paper’s “larger implications” for the history of the Black Death and the pandemic it kicked off, she said. Among these are what conditions could have prompted the disease to spill from local rodents into people near Lake Issyk-Kul, or whether the infection might have instead been introduced from elsewhere. 

“Moreover, we still do not know how this local outbreak was historically connected to the earliest recorded incidence of the Black Death in the Black Sea region in 1346,” Varlık said. “Evolutionary studies of Yersinia pestis and our modern experience with the COVID-19 pandemic teach us that it may be nearly impossible to establish [the] ‘true origin’ of pandemics.”

[Related: You could get the plague (but probably won’t)]

The new findings suggest that the ancestor of the Black Death strain showed up considerably later than previous work has indicated, said Vladimir Motin, a microbiologist at the University of Texas Medical Branch at Galveston who studies Y. pestis. Earlier studies suggested it caused local outbreaks in Asia for at least a century, he said.

“Right now it’s a good hypothesis; is it true or not, I don’t know,” he said. “But it’s definitely an interesting question which we should take into consideration.”

Monica H. Green, an independent scholar who specializes in medical and medieval history, agrees with Varlık that the paper establishes 14th-century remains in Kyrgyzstan were infected with Y. pestis. But Green, who has studied the presence of plague in western Asia in the 1250s, isn’t convinced the findings determine the time period when this ancestral strain appeared. The plague bacterium mutates slowly when it’s circulating in marmots, she points out, which means that the strain might have made its debut well before the outbreaks.

“Have they documented emergence of a new stage in plague’s history…in the 14th century?” Green said in an email. “Or have they documented the persistence of a new lineage that had already been dispersing for several decades by the time these two communities to the west of Issyk-Kul were struck?” 

She suspects that the strain Slavin and his team retrieved is a “cousin” of the bacteria that spread westward to cause the Black Death. To unravel the pandemic’s genesis, researchers will need to collect more ancient DNA samples from the region and beyond. 

The history of plague offers important clues toward understanding how pandemics begin and spread, Green said. “We have never needed rigorous debate about pandemic histories more than now.” 

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Another fitness trend is heating up across the US—and it involves stretching and sweating in dry, desert-like heat.

Rather than cranking up the temperatures in studios with traditional forced air systems, infrared hot yoga uses heated panels to mimic the sun’s warmth. The radiant energy warms practitioners’ bodies and the floor rather than the surrounding air. 

Proponents say this less swampy form of yoga offers health benefits ranging from increased flexibility to weight loss and “detoxing” the body through sweat. But as with infrared saunas (which also use this dry kind of heat), there isn’t any evidence to back up most of these claims. That said, infrared hot yoga does offer many of the same advantages of other styles of yoga, and might make it easier for some people to practice at higher temperatures.

“It was definitely a different sensation, practicing in the dry heated conditions,” says Stacy D. Hunter, the director of the Cardiovascular Physiology Lab at Texas State University, who has practiced hot yoga for more than a decade and studies how the heated and non-heated forms affect vascular health. “It didn’t really feel hotter [at first] because there was practically no humidity there, but when you get to practicing … it’s very difficult, it feels very hot, and it’s very mentally challenging.”

Hot yoga vs. regular yoga

“Yoga in general is great for so many reasons, for physical and mental health,” says Cara Hall, a physician who specializes in primary care sports medicine at Keck Medicine of USC. 

The movements improve strength, flexibility, and balance. Research also indicates that yoga can ease lower back and neck pain, reduce stress, and improve sleep. When practiced consistently, Hunter says, it can lower blood pressure and cholesterol levels and helps the blood vessels dilate to improve blood flow. She and her collaborators are further investigating how non-heated yoga affects immune function.

During a hot yoga class, the room is heated to around 90 to 105 degrees Fahrenheit, which lets participants limber up and sweat more. This variation is intended to further boost flexibility and deepen stretches.

“For someone who is training or conditioning to do some sort of performance event in a hot place or just trying to peak their performance, hot yoga may be a good way to kind of acclimate to that environment or to be able to push yourself a little more,” Hall says.

[Related: 5 stretches you should do every day]

However, Hunter notes, the overall amount of calories burned during hot yoga and other traditional yoga styles are pretty similar. She and her team have further found that hot yoga and non-heated yoga have similar effects on blood vessel dilation. “It didn’t appear that the heat conferred any additional benefit in terms of vascular function,” she says. 

“A lot is still undocumented in terms of the benefits of hot yoga,” Hunter adds. “Some of the claims that have been made about it have definitely preceded the evidence to back that up.” 

Let’s talk about detoxing

One particularly shaky claim is that hot yoga, and infrared hot yoga in particular, help with “detoxification.” But the main thing to remember is that the primary role of sweating is to cool the body, not to flush out harmful substances. In fact, when you work up a sweat, you lose electrolytes, which include minerals that are essential for many bodily functions. “I am unaware of any detoxification through sweating,” Hunter says. 

The liver is the main organ responsible for dealing with waste products and any damaging substances that a person might encounter, like ammonia. “When we’re talking about losing toxins, I would leave that to the liver,” Hall says. 

In general, it’s possible that practicing in dry heat could lessen the risk of overheating during class, Hunter says, although more data is needed to confirm this. “Humidity makes it harder for sweat to evaporate … it’s really the evaporation of the sweat that carries the heat away from the body,” she says. “With the dry infrared heat you can definitely tolerate higher temperatures as well, compared to the heat combined with the humidity like in the Bikram, or traditional, hot yoga style.” (Bikram is a particularly intense form of hot yoga popularized in the 1970s by a self-prescribed Indian guru, who later fled the US after multiple accusations of sexual assault). 

[Related: How much exercise do I need to stay healthy?]

Regular hot yoga can be pretty “sticky,” Hall acknowledges. “The infrared [heat] may make it a more pleasant experience, which may help you further along your practice because it feels less stuffy, more natural, etcetera,” she says. “I think the main target for this is going to be the people who are doing hot yoga to begin with and potentially make it more comfortable.”

Hunter is also running a study to determine whether infrared hot yoga may improve vascular health in Black adults in the US, who tend to be disproportionately sensitive to blood pressure changes. Still, she suspects that the practice doesn’t offer many health benefits beyond the classic kinds of yoga.

What to consider before you try infrared hot yoga

There are a few potential risks to keep in mind when practicing infrared and other other kinds of hot yoga.

Practicing in toasty conditions makes for a vigorous workout, but it can lead to injuries when people push themselves too far because they’re looser than usual. Hot yoga also comes with an increased risk of dehydration and overheating. 

If you plan to try a class, Hall advises to hydrate before it starts, and don’t be afraid to take a break if you need it. 

[Related: The best (and worst) beverages to sip when you’re dehydrated]

“I caution people not to go past their point of comfort; it should feel like a bit of a stretch but nothing extreme and definitely do not push through pain,” she says. “That is a risk that you run with hot yoga: overdoing it.”

It’s also important to familiarize yourself with the signs of heat-related illnesses. “I have been in situations in which there has been someone in the room who starts to be disoriented, or maybe they look like they’re going to pass out, and the instructor will tell them not to leave the room. That is dangerous,” Hunter says. “Definitely don’t listen to that instruction.”

There are a number of conditions that can make it unsafe for people to practice infrared and other forms of hot yoga, Hunter says, such as heart disease, pregnancy, very high blood pressure, or being on certain medications. 

If you end up committing to an infrared hot yoga practice, “just set your expectations realistically going into it,” Hall says. “The focus should be on it getting you stronger, potentially some mental health benefits, and flexibility benefits, rather than, ‘How much can I sweat?’”

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In the next few weeks the Supreme Court will rule in a case that could overturn Roe v. Wade and demolish the constitutional right to an abortion.

If this happens, the decision would have far-reaching and damaging impacts on every aspect of reproductive health care, experts say, including for people who experience miscarriages. The medicines and surgical procedures used in abortions are also used to treat miscarriages, so restricting abortion access means that people in many states will have fewer options to safely manage the unexpected loss of their pregnancies.  

“For those of us on the ground who care for pregnant patients regardless of what their outcome is, our hands are tied and will be further tied to deliver evidence-based care,” says Courtney Schreiber, an OB-GYN and chief of the division of family planning at Penn Medicine.

The US already has “an abysmal public health record” compared with similarly wealthy countries for severe complications and deaths in pregnant people, says Aileen Gariepy, an OB-GYN and director of complex family planning at Weill Cornell Medicine in New York. Reversing Roe v. Wade will only worsen this problem, including the people who will be unable to access care for their miscarriages.

[Related: What science tells us about abortion bans]

Miscarriages occur when a fetus dies before the 20th week of pregnancy (the loss of a pregnancy after this point is known as a stillbirth). Most happen in the first trimester, and an estimated 10 to 20 percent of known pregnancies end with miscarriages. In fact, it’s the most common complication in pregnancy, Schreiber says.

“We can’t assume that just because a person is pregnant that everything will go smoothly, perfectly, and result in a healthy baby at the end of the pregnancy,” she explains. 

When a person miscarries in their first trimester, they have three options. One is to watch and wait to see if the body will recover from the miscarriage on its own. Another is to have a minor surgical procedure called a suction dilation and curettage to empty the uterus. This procedure is also performed when the placenta becomes stuck after a normal, full-term vaginal delivery, Gariepy says.

The third option is to take medication that prompts the uterus to contract and push its contents out through bleeding and cramping. “Women who want medical management might like the privacy of being in their homes, being surrounded by their loved ones,” Garipey says.

In these cases, the miscarrying person receives a pair of medications called mifepristone and misoprostol. Physicians used to prescribe misoprostol on its own. However, Schreiber and her colleagues reported in a 2018 paper in the New England Journal of Medicine that the drug is significantly more likely to clear the uterus when paired with mifepristone—as is done in medical abortions. 

“By decreasing access to these medications for abortion, the care for miscarriage patients will also be adversely impacted,” she emphasizes.

For people in the first trimester of pregnancy, limited access to effective medical miscarriage treatment options is rarely life-threatening, Gariepy says. But it does mean that the pregnant person will have to endure more days of bleeding and cramping and be more likely require a surgical procedure. (This is already happening in Texas, which banned most abortion care last September). “That burden will be physiologic; it might be psychological; it could be socioeconomic if you have to take days off of work,” Gariepy adds. 

Losing a pregnancy can be more dangerous after the first trimester. At that point the treatment options are to induce labor or a procedure called dilation and evacuation. If “we try to wait for Mother Nature to empty the uterus, women can become very sick. They can become septic; they can lose their uterus; they can die,” Gariepy says. But “if that fetus still has a heartbeat, any intervention we take at that point is an abortion—so if abortion is illegal and criminalized, then more women will die.”

This is exactly what happened to a woman named Savita Halappanavar in Galway, Ireland, in 2012. After being denied timely treatment when she began to miscarry 17 weeks into her pregnancy, Halappanavar developed an infection and died. Her case became a rallying point, and in 2018, Ireland passed legislation loosening some restrictions on abortion.

In the US, patients at certain religious hospitals have also become seriously ill after being refused treatment for miscarriages.

“We already are seeing in states where abortion restrictions have been implemented that … patients and pregnant people are getting sicker, maybe winding up with sepsis or profound amounts of blood loss before they can be treated,” Schreiber says. “People will be taking more time away from work, requiring more childcare and emotional support after these events because of how traumatic we as a society have made them, when [miscarriages] can be safe and easily cared for.” 

[Related: A simple blood test could save new mothers. Why aren’t more doctors using it?]

In the future, there might even be a shortage of physicians who can provide these treatments. Schreiber foresees that fewer medical students will choose to go into obstetrics and gynecology, knowing that they might not be allowed to deliver proper care to their patients. Medical students in some places are already not being trained to treat abortions—and miscarriages.

“The number and types of legal restrictions state by state and are extremely laborious and confusing both for providers and for patients, so knowing what is legal, what is illegal, and working within the legal system in order to provide safe care is another critical consideration,” Schreiber says. 

In states with particularly restrictive laws, people who miscarry will face an additional danger: being prosecuted on suspicion of having a self-induced abortion. 

“If you’re miscarrying at home and are bleeding heavily and are afraid to go to the emergency room because you don’t want to be arrested, then you might be more likely to stay home,” Gariepy says. “And that could be dangerous.”

Doctors and reproductive rights advocates are now planning for a “patchwork of protection” across the US, “where some women will have their autonomy and health upheld and their dignity maintained, and other women will need to seek care elsewhere,” Gariepy adds. 

“There is a reason that the doctor-patient relationship occurs between the doctor and the patient, and not the doctor and patient and the legislator, and interfering with medical care is misguided and will result in harm,” she says. 

What’s more, the rollback of reproductive rights comes at a time when understanding and treatments for early pregnancy loss have never been better, Schreiber points out. “The problem is being able to deliver that evidence-based care,” she says. “The effects on females in the US will be felt for years and decades to come.” 

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Great whites are the largest predatory sharks to roam the world’s seas, reaching up to 20 feet in length. But that wasn’t always the case. Millions of years ago, the megatooth shark family spawned one of the largest carnivores that ever lived: Otodus megalodon, which is estimated to have grown to 50 to 60 feet. 

Yet the immense megalodon abruptly vanished from the fossil record around 3.6 million years ago—not long after the emergence of great white sharks. Scientists have speculated that the two species might have competed for prey, ultimately contributing to megalodon’s extinction. 

A study published on May 31 in Nature Communications offers indirect support for this idea. Researchers compared the chemical composition of teeth from living and extinct sharks, and concluded the great whites and megalodon occupied similar rungs of the prehistoric food chain.

“Megalodon is an enigma in many ways,” says Alberto Collareta, a paleontologist at the University of Pisa in Italy, who wasn’t involved with the research. Collareta has studied bite marks, probably made by megalodon sharks, on the fossilized bones of small baleen whales and pinnipeds (the group encompassing seals and their relatives). Our understanding of megalodon’s diet is based primarily on such markings and on the sharks’ serrated teeth, which are more likely to fossilize than their cartilage skeletons.

The new paper “is very helpful and very insightful in that it provides quantitative, geochemical data to check against previous hypotheses,” Collareta says. 

Great white sharks began venturing beyond the Pacific Ocean and showing up in seas around the world about 4 million years ago. That event may have hastened the demise of megalodon, as Robert Boessenecker, a paleontologist at the College of Charleston in South Carolina who also wasn’t involved in the research, and his colleagues previously suggested.

“At the time I figured it was a bit of a shot in the dark, and didn’t really think too hard about how the hypothesis would be tested,” Boessenecker wrote in an email. The new study “not only attempted to do so, but found evidence strengthening the hypothesis!”

An animal’s diet reveals a lot about its behavior and role in the ecosystem, says Jeremy McCormack, a geoscientist at Goethe-University Frankfurt in Germany and co-author of the new paper. Within each ecosystem, animals exist in a hierarchy known as trophic levels—whether they’re herbivores, top predators, or somewhere in between. Researchers typically determine an animal’s level by looking at different versions, or isotopes, of nitrogen in their bodies. Animals accumulate the “heavier” nitrogen isotope from their prey: The isotope is more prevalent in predators’ tooth dentine, bone collagen, and keratin. However, these tissues don’t fossilize well, so the technique only works for modern and recently-fossilized animals. 

By contrast, zinc—an essential nutrient for plants, animals, and other organisms—is deposited in the strongest part of the teeth: the enamel, or in the case of sharks, enameloid. This is preserved when the teeth fossilize. What’s more, the proportion of “lighter” zinc increases relative to the “heavier” zinc isotope in animals higher up the food chain. Scientists have only recently begun using this technique, McCormack says, and his team’s study is the first to apply it to sharks.

The researchers examined teeth from 20 present-day species of sharks and other fish, including tiger sharks, bull sharks, mako sharks, monkfish, and halibut, as well as 14 fossilized sharks. The analysis included both present-day and fossilized great white shark teeth. 

[Related: Great whites don’t hunt humans—they just have blind spots]

When they compared the zinc levels in megalodon and fossilized great white shark teeth, they found similar ratios of light to heavy zinc isotopes. This indicates that the animals fed at similar positions in the food chain. They may have targeted some of the same marine mammals.

“I wouldn’t necessarily say they were definitely the top predators of that marine ecosystem,” McCormack says. But both shark species “were high up the food chain for sure.”

Tiger shark teeth had the same zinc isotope ratios as prehistoric ones, suggesting that their trophic level hasn’t changed much for millions of years. But modern great white sharks seem to have ascended to a somewhat higher level than their predecessors. Additionally, the shark with the highest trophic level was not megalodon but its ancestor Otodus chubutensis. 

The rise and fall of certain prey animals—petite baleen whales—may underlie these trophic shifts. 

Baleen whales consume vast quantities of organisms low in the food chain such as krill, instead of the bulkier fish, seals, and other animals favored by toothed whales such as orcas. Baleen whales were “quite rare” during the time of O. chubutensis, Boessenecker said. This means that O. chubutensis probably fed on toothed whales instead.

[Related: Scientists discovered new shark species with chainsaw-like noses]

Later, baleen whales—much smaller than their present-day relatives—appeared on the scene and might have been fair game for megalodon and early great whites. These whales mostly disappear from the fossil record around the time that megalodon went extinct. Their absence may have led modern great whites to dine higher in the food chain. 

Expanding the zinc isotope analysis to marine mammals that megalodon and great white sharks might have eaten could add weight to the conclusion that the animals fed at similar trophic levels, Collareta says. 

“We show for the first time that zinc isotopes do preserve the dietary signal over millions of years,” McCormack says. “This method is very promising, but of course we need to investigate this further to really get a grasp of how zinc behaves within an organism and throughout different trophic levels.” 

Other paleontologists are excited by the promise of ancient zinc. “This is a powerful new tool to further examine trophic structure of extinct marine vertebrates,” Boessenecker said, “and I eagerly look forward to similar methods being used on fossil marine mammals.”

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When the first dinosaur fossils were recognized in the mid-19th century, scientists envisioned that the creatures were basically giant, lumbering lizards. They also presumed that dinosaurs were like present-day, cold-blooded lizards, meaning that their body temperature depended on the surrounding environment. However, this notion was later fiercely debated.  

“The general picture that we have of dinosaur physiology has changed quite a bit through the last [several] decades,” says Jasmina Wiemann, a molecular paleobiologist at the California Institute of Technology. “Our understanding of what dinosaurs looked like and lived like is directly related to the question of whether they were cold-blooded, warm-blooded, or somewhere in between.” 

A new analysis published by Wiemann and her collaborators on May 25 in Nature indicates that the ancestors of dinosaurs were warm-blooded, or capable of maintaining a constant internal temperature. The researchers used a new technique to estimate the metabolic rates of modern and extinct animals based on the molecular composition of their bones. They concluded that many iconic dinosaurs such as Tyrannosaurus rex and the giant sauropods were warm-blooded, but cold-bloodedness later emerged in some dinosaurs such as Stegosaurus. 

Enrico Rezende, an evolutionary biologist at Pontifical Catholic University of Chile who has studied the evolution of warm-bloodedness, or endothermy, calls the findings “quite impressive.”

The results are “not entirely surprising, but it’s definitely good to have some estimate of metabolic levels,” he says, explaining that it breaks away from rigidly categorizing dinosaurs as warm-blooded or cold-blooded. “Essentially what this shows is that we have this whole gradient of metabolic levels.” 

Modern lizards or crocodiles must bask in the sun to raise their body temperature, while warm-blooded animals such as birds and mammals don’t need to do this. Being endothermic could have allowed dinosaurs to be more active and range over larger areas, Rezende says. They would also be less vulnerable to chilly temperatures, which means they could be more active at night and would fare better on elevated terrain or at high latitudes. On the other hand, warm-blooded dinosaurs would require a lot of energy to fuel their high metabolisms, which means they would need to spend a lot of time feeding.

“Understanding the metabolic levels would tell us quite a lot about how they could interact and how these ecosystems could be built,” Rezende says.

[Related: Spinosaurus bones hint that the spiny dinosaurs enjoyed water sports]

Researchers have used various procedures to explore the extent to which dinosaurs were able to generate their own heat, says Lucas Legendre, a paleontologist at the University of Texas at Austin. One line of evidence comes from body temperature estimates based on temperature-sensitive minerals preserved in fossils. Other researchers study the growth rings in dinosaur thighbones to gauge how fast the animals grew. Legendre and his colleagues have also used blood vessel and bone cell size to infer that carnivorous dinosaurs had high metabolic rates close to those of today’s birds. 

The Nature paper indicates that, in terms of physiology, dinosaurs typically had more in common with their closest living relatives—birds—than with lizards, Legendre says. “This is a new piece of evidence that confirms what a lot of researchers have been saying for the past decade,” he says. 

For the new work, the researchers took a more direct approach than earlier investigations, says Matteo Fabbri, a paleontologist at the Field Museum of Natural History in Chicago and coauthor of the study. The team examined byproducts of metabolism—the process by which animals convert nutrients and oxygen into energy—preserved in newly-formed as well as fossilized thighbones. 

“It is the metabolism that determines whether a lot of excess heat is generated as part of the breathing process and whether an animal is cold-blooded or warm-blooded,” Wiemann says.

During this process, chemicals called reactive oxygen species form and generate molecules called advanced lipoxidation end-products. These leftovers build up and “leave a fingerprint in pretty much every tissue,” Rezende says. An animal with a high metabolic rate uses more oxygen than one with a low metabolic rate, so it should have higher levels of these compounds in its body. 

Wiemann and her team scanned the bones of 30 fossilized animals and 25 modern birds, mammals, and reptiles using techniques called Raman and Fourier-transform infrared spectroscopy. This allowed them to measure the accumulated amounts of advanced lipoxidation end-products. 

“We basically use these data to infer the evolution of metabolism,” Wiemann says. “What we figured out is that dinosaurs were ancestrally warm-blooded.”

[Related: The fiery end of the dinosaurs kicked off the golden age of mammals]

The findings indicate that endothermy independently evolved in the group encompassing dinosaurs and the flying reptiles known as pterosaurs, in mammals, and in marine reptiles known as plesiosaurs. The researchers calculated particularly high metabolic rates for a long-necked diplodocid, Allosaurus, and birds, while T-rex had a somewhat lower metabolic rate than other carnivorous theropod dinosaurs. Strikingly, several of their more distant relatives had metabolic rates on par with modern lizards, indicating they were cold-blooded, or ectothermic. These included Stegosaurus, Triceratops, and a duck-billed hadrosaur.

“That is quite fascinating because it means the range of metabolisms realized in dinosaurs is a lot broader than originally thought,” Wiemann says. “That brings up interesting questions as to what triggers the evolutionary increase or decrease in the metabolic rate, and what does this mean for the lifestyles of the animals?”

Researchers have previously suggested that warm-bloodedness helped prehistoric birds and mammals adapt during the mass extinction that killed off the rest of the dinosaurs about 66 million years ago. However, the evidence that many Late Cretaceous dinosaurs had high metabolic rates hints that other traits such as body size were probably key to the survivors’ success, Wiemann says.  

The findings will need to be verified with further analyses that include more extinct animals, Legendre says. Still, the metabolic byproducts Wiemann and her team probed offer a source of data that researchers can compare with other traits.

“The fact that they used this new method adds one additional piece of the puzzle,” Legendre says. “Hopefully we’ll be able in the next few years to come up with a more precise picture of how dinosaurs and their close relatives were able to produce metabolic heat.”

Updated (May 26, 2022): The headline of this story has been updated to better reflect the research study’s question and the debate about dinosaur endothermy.

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At first glance, the 5-inch-long wandering salamander doesn’t appear particularly suited for a life of aerial acrobatics. The amphibians, which can spend their entire lives in the crowns of California’s redwood trees, don’t have the membranes or skin flaps seen in gliding lizards, frogs, or mammals. But when disturbed, wandering salamanders will launch themselves into the air and drop considerable distances onto the branches below. 

These aren’t frantic, uncontrolled plunges, scientists reported on May 23 in Current Biology. When the researchers dropped wandering salamanders, Aneides vagrans, into wind tunnels, the amphibians assumed a position similar to that of human skydivers and used their tails and feet to slow down and guide their descent. This discovery suggests that other tree-dwelling animals may also have hidden gliding abilities, the team concluded.

“The salamander is surprising because it doesn’t look like it should be able to do anything in the air whatsoever,” Jake Socha, a biomechanist at Virginia Tech who studies flying snakes, another group of animals that manage without conspicuous aerodynamic traits. “It seems to be that numerous animals have evolutionarily stumbled upon similar sets of features which involve behaviors that will help them to control their body in the air.” 

The canopies of redwood forests are a world unto themselves, says Christian Brown, a doctoral candidate in biology at the University of South Florida and coauthor of the findings. Over hundreds of years, thousands of pounds of debris can build up in the crooks between branches, forming spongy mats that collect water and teem with plants and small animals.  

“When you climb up into the tree, if you look down you don’t really see the forest floor—you just see more fern mats arranged below you,” Brown says. “It’s kind of a vertical labyrinth of fern mats.”

Wandering salamanders may leap to escape from predators or to find more promising habitats if food or mates are in short supply. Simply crawling down the trunk of the tree might demand a great deal of time and comes with the risk of drying out or being hunted. “If I take the gravity elevator, I’ll be there in seconds and I don’t have to risk any of these things,” Brown says. 

He suspects that most of these jumps take place within the zone of 40 to 80 meters (131 to 262 feet) above the ground. Given how light the salamanders are and the cushy padding of the forest floor, plummeting all the way to earth wouldn’t necessarily be fatal. But even if a salamander survives a misjudged fall, it will likely be cut off from food and mates, might lack the energy to scamper back to shelter, and could be devoured by larger species such as the Pacific giant salamander.

All of these hazards give the amphibians a powerful incentive to develop the ability to maneuver in midair. Brown and his team previously found that wandering salamanders jump a little differently than other species. Tricks such as launching off two feet rather than one likely give the animals more control once airborne, he says.  

For the new experiments, Brown and his collaborators took a closer look at how wandering salamanders performed in the air. They also examined three other species that spend varying amounts of time in the trees. The researchers dropped members of all four species into a wind tunnel, which “basically creates an animal that hovers in place and simulates an endless descent,” Brown says. 

Unsurprisingly, the wandering salamanders seemed most comfortable with this situation. They positioned themselves like skydivers to reduce their falling speed, a behavior the researchers refer to as parachuting. The salamanders take on a specific body position, “splaying their legs out, getting those big hands and feet out far away from the body, and craning the neck back and pointing the tail up and forming this big U-shape,” Brown says. The team found that about 10 percent of their vertical velocity, or speed, had been shaved off when they used this parachuting posture. 

The amphibians also sometimes pumped their tail up and down and moved their limbs to move horizontally. Gliding this way probably helps the animals direct themselves towards fern mats to break their fall. 

Brown likens the salamanders’ skills at keeping themselves upright to a person using a paddle to control their kayak.

“What really shocked us was that the animals literally never went upside down or lost control unless they ran into a wall,” he says. “The fact that they did it every single time was really revealing to us.” 

[Related: These male spiders fling into the air to escape post-coital cannibalism]

Another closely related species, the arboreal salamander, also was fairly adept at controlling its descent. By contrast, the other two species, which come from the same region but don’t typically venture into trees, frequently flailed about without altering their speed or direction.    

The next step is to confirm that the wandering salamanders perform their impressive maneuvers in the wild, Brown says. The researchers have begun investigating how wind and other variables affect the falling amphibians and how well they can navigate in midair. 

Wandering salamanders have a few distinct anatomical characteristics that might underlie their aerial abilities. Compared with other tree-climbing salamanders, their bodies are a bit flatter, their feet larger, and their tails bendier. Brown and his team are also running computer simulations to understand how these adaptations influence the way that air flows over the salamanders’ bodies during a jump. 

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In the waters of the Red Sea off the coast of Egypt, bottlenose dolphins have a highly unusual relationship with their reef habitat. Divers frequently witness the marine mammals rubbing their faces and bodies against certain corals and sponges, even waiting in orderly lines to approach the invertebrates. 

“You get very excited to see that for the first time,” says Angela Ziltener, a wildlife biologist at the University of Zurich who has studied dolphins in this region for more than a decade. When she initially witnessed the behavior, she wondered if the dolphins were brushing up against the corals because it simply felt good or if there was something more to it.

To find out, Ziltener and her collaborators analyzed tissue samples from the invertebrates. They identified 17 chemicals that were bioactive, or likely to have an effect on living cells or tissues. This suggests that rubbing against the corals and sponges might actually help the dolphins keep their skin healthy and fight infections, the team reported on May 19 in the journal iScience.

“These are potent active compounds that we found,” says Gertrud Morlock, an analytical chemist and food scientist at Justus Liebig University Giessen in Germany and another coauthor of the paper. When they come into contact with the body, she says, the coral compounds may work similarly to the antibacterial creams people put on their skin.

Scientists have occasionally observed dolphins performing similar rubbing behaviors in the Bahamas and Florida, she and her colleagues wrote. The population they focused on included 360 Indo-Pacific bottlenose dolphins in the Northern Red Sea. As the researchers watched the dolphins visiting the corals and sponges, they noticed a few patterns. 

Calves under one year of age hung back and watched the adults brush themselves against the invertebrates. The adults only did the rubbing under calm and quiet conditions. “If they’re disturbed by boats, you don’t see this behavior,” Ziltener says. “They need to be relaxed.”

Groups of dolphins regularly queued up behind each other and took turns gliding towards and rubbing against the coral or sponge. “It’s very organized,” Ziltener comments.

And not just any invertebrate would do. The dolphins zeroed in on soft, branching gorgonian corals as well as harder leather corals and certain sponges. They often slid into the branches of gorgonian corals multiple times, allowing several body parts to brush against them. By contrast, the dolphins pushed a particular body part such as the head or fluke forcefully against the surfaces of the more compact organisms. On occasion, the dolphins would pull a leather coral from the seabed, carry it in their mouths for a few minutes, and then wave the coral around until yellowish or greenish substances leaked out and stained their head and snout.

The researchers identified a variety of intriguing properties in compounds extracted from tiny pieces of the dolphins’ favored corals. Many of the molecules combatted bacteria, Morlock says, and several resembled the hormone estrogen (which in humans helps keep the skin firm and moisturized).

[Related: Supercharged blood helps some dolphins dive 1,000 meters]

While the findings are suggestive, they aren’t enough to prove that the dolphins are seeking out the invertebrates to self-medicate, Ziltener acknowledges. “So far in this publication, we just can show the link between the invertebrates and the dolphins,” she says. 

While skin samples from the dolphins might provide more conclusive evidence that secretions from the corals and sponges help prevent or control infections, the researchers intend to disturb the marine mammals as little as possible. However, Ziltener says, investigating the dolphins’ behavior in more detail may offer insights about when and why they rub against the marine invertebrates. She plans to track how much coral-rubbing differs based on the age or sex of the dolphins, and which body parts the dolphins press against the organisms most often. 

Moreover, Ziltener adds, the findings highlight the importance of conserving vulnerable reef ecosystems.

“There’s so much more to discover in coral reefs,” she says.

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Around 540 million years ago, Earth’s life underwent a burst of evolution that gave rise to the major groups of animals alive today, including those with backbones and those that hunt prey. This bonanza is known as the Cambrian explosion. Based on the fossil record, animal life appeared to be comparatively sparse and looked very different from the creatures that emerged later in the fossil record. 

For decades, paleontologists have been searching for a way to explain the stark contrast in diversity. One leading theory is that an environmental disaster wiped out most animal life prior to the Cambrian explosion. A new analysis, however, indicates that earlier animals had already formed complex ecosystems before the Cambrian Period kicked off. Researchers examined data from fossil beds around the world and determined that animal diversity may have dipped during a period known as the late Ediacaran, around 572 million to 541 million years ago. As Ediacaran organisms became more specialized, some species couldn’t keep up with their neighbors, the team reported on May 17 in the journal PLoS Biology.

“What this is showing very distinctly is that actually the Ediacarans were the precursors to the Cambrian,” says Emily Mitchell, a paleontologist at the University of Cambridge and coauthor of the findings. “It was very much the start of the Cambrian explosion.”

[Related: A close look at amber fossils that have stuck through the ages]

For around 3 billion years, single-celled organisms dominated Earth’s seas. The first animals emerged during the late Ediacaran, and some of the oldest organisms organisms dwelled in deep water and resembled plants with feathery-looking structures branching off a central stem. Others had segmented disk-like bodies. 

“One of the really unique things about the oldest of these Ediacaran organisms is they have this strange fractal branching—they had branches of branches of branches,” Mitchell says. “Studying Ediacaran organisms is really hard because their body plans are unlike anything else alive today or elsewhere in the fossil record.”

Fortunately—for paleontologists, anyway—many Ediacaran communities were preserved in ash and debris from volcanic eruptions, mudslides, and other sudden disasters. “It’s basically like Pompeii; everyone’s existing happily and then suddenly you have this massive burial event,” Mitchell says. “You have these amazing snapshots of Ediacaran life.” What’s more, most Ediacaran remains went undisturbed because there weren’t yet scavengers to dig up the carcasses. Instead, Ediacaran animals often ate by filtering scraps of decaying organic matter and plankton from the water.

To understand these organisms is to understand the origin of complex life on Earth—and the likelihood it exists elsewhere in the universe, says Simon Darroch, a geobiologist at Vanderbilt University who wasn’t involved in the research. “We really need to work out what these organisms are, how they formed and interacted in communities, and then what happened over the Ediacaran-Cambrian boundary,” Darroch says. “It’s a crucial interval in Earth’s history.” 

In an attempt to investigate how these animals lived and interacted with each other, Mitchell and her collaborators examined records of 86 Ediacaran fossil beds. Those represented 124 species from around the world, like the iconic Charnia and Dickinsonia. The study authors also examined previously published data on Ediacaran environmental conditions inferred from the surrounding rocks. The researchers evaluated how often different species appeared alongside each other, and in what environments. 

In the most ancient sites, the team identified few links between any particular species or habitats. But that changed with younger groups of fossils. Certain organisms tended to group at the same locations, while others never overlapped. Communities of Ediacaran organisms also varied more distinctly depending on the depth or geographic region they dwelled in.

“What that’s telling us is these species are adapting to each other and their environment,” Mitchell says. 

This pattern—of increasing specialization over time—is the opposite of what’s expected after a cataclysmic event. When a massive volcano erupts or a dinosaur-killing asteroid strikes Earth, the species that survive or emerge afterward tend to be hardy generalists that can endure a broad range of conditions. That doesn’t fit the bill for the Ediacarans, Mitchell and her team observed. 

“We see an increase in ecological complexity,” she says. “Even though we have a decrease in the [overall] number of species, that’s because they’re specializing, they’re finding their particular niches, rather than something external is killing them off.”

[Related: Eastern Africa’s oldest human fossils are more ancient than we realized]

More detailed analysis will be needed to determine the pressures driving these patterns, Mitchell says. Two species might have occupied the same area because they had similar nutritional needs. Or they may have benefitted from each other’s presence, similarly to present-day plants and pollinators. Another pair of species might not coexist because they’re suited to different habitats, or because one animal will outcompete the other if they share the same space. 

At this stage, Darroch says, there still isn’t enough evidence to rule out a catastrophic extinction at the end of the Ediacaran. However, he adds, the new paper does indicate that Ediacaran ecosystems were “certainly way more dynamic” than they’ve been given credit for. 

Researchers have determined that many animal innovations, such as hard exoskeletons and predatory behavior, originated in the Ediacaran’s final chapter. It “makes intuitive sense” that these organisms were beginning to settle into more specialized roles and seek out different habitats, Darroch says.

“The more you look into the Ediacaran the more you can see that it’s a gradual crescendo,” he says. The emergence of modern animal groups happened relatively gradually, and “finally went nuts”  at the start of the Cambrian period. “But the roots of the explosion,” he adds, “go way deeper.”

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On January 15, the cataclysmic eruption of a submerged volcano in the South Pacific devastated the archipelagic nation of Tonga, unleashed tsunamis around the world, and created a sonic boom heard as far away as Alaska. 

The blast was captured by a host of sensors located in land, sea, and sky. Two groups of scientists published their analyses of this data on May 12 in the journal Science. 

One team concluded that pressure waves from the event were comparable in scale to those from the massive 1883 Krakatau eruption in Indonesia, which unleashed clouds of ash that reached 50 miles high and explosions that could be heard 2,200 miles away at its peak. The second group explored how the pressure waves caused tsunamis to arrive on distant shores hours earlier than expected. This information can help scientists better understand the processes underlying eruptions and improve tsunami early-warning systems, the researchers say.

“There’s been nothing like this in the modern digital era,” says Robin Matoza, a geophysicist at the University of California, Santa Barbara and coauthor of one of the papers. “It’s a really remarkable event.”

Randy Cerveny, a meteorologist at Arizona State University and rapporteur on weather and climate extremes for the United Nations’s World Meteorological Organization, described the two papers as “fascinating work.”

“The more information we have now—and continued analyses of that available information—hopefully will make us better prepared for future eruptions of such incredible magnitude,” he said in an email.

The volcano responsible for all this turmoil lies 40 miles from Tongatapu, the largest island of Tonga. It’s roughly 12 miles across and topped by 3-mile-wide caldera with two “lips” that protrude above the water. The Hunga volcano experienced several minor eruptions from 2009 to 2015. A series of more violent outbursts began last December, climaxing with the massive January 15 eruption, which sent a cloud of ash more than 20 miles into the sky.

[Related: How to survive a tsunami]

Matoza’s team, which included researchers from 17 countries, investigated the pressure waves emitted by the powerful eruption. They compiled measurements from seismometers, buoy-based pressure sensors, hydrophones, weather satellites, instruments that record the bending of radio waves as they pass through the Earth’s atmosphere, and more.

The researchers focused in particular on Lamb waves, which are low-frequency perturbations that travel along the surface of the Earth at roughly the speed of sound. Cerveny likens the phenomenon to the behavior of a jiggly dessert.

“Think of an explosion from the bottom of a huge container of, say, Jell-O and how the pressure ripples of compressed jello would spread out horizontally from the explosion site,” he said.

Lamb waves typically span the full depth of the atmosphere, allowing researchers to track them with a variety of sensors both on the ground and in satellites, said Siddharth Krishnamoorthy, an aerospace engineer at the NASA Jet Propulsion Laboratory in Pasadena and coauthor of the paper. “The amplitude of the Lamb wave that we observed here was not so high as to cause damage, but it does help us understand wave propagation in the atmosphere and characteristics of the eruption itself,” he said in an email.

He and his collaborators observed that the Lamb wave released by the Hunga eruption was so powerful that over a period of six days it circled the Earth multiple times. The team concluded that the wave was on par with that of the infamous Krakatau eruption of 1883 in size and distance traveled, and more than 10 times larger than the one produced by the 1980 Mount St. Helens eruption.

“It shows just how extreme the January 2022 eruption of Hunga volcano actually was,” Cerveny said. “If the Hunga eruption had been primarily above sea-level (like the Krakatau eruption), the effects would have been something not witnessed in nearly 150 years.” 

Krakatau’s upheaval was recorded by around 50 weather barometers stationed around the world, whereas the Hunga eruption was documented by thousands of sensors. This has given scientists an “unparalleled” global dataset for an explosion this size, Matoza says. In the future, he and his colleagues hope to deepen their understanding of Hunga’s eruption by drawing on data from home weather stations belonging to non-scientists around the globe. 

“There’s real potential here to gather up all of this extra data to do even better characterization of this wavefield,” he says.

The vast majority of tsunamis are generated by earthquakes. Early-warning systems are based on these types of waves and can predict their arrival time to within minutes, said Lucie Rolland, a geophysicist at the Côte d’Azur Observatory in Valbonne, France, and another member of Matoza’s team. However, the tsunamis created by the Hunga eruption were significantly different, with the first waves arriving more than two hours earlier than usual. The tsunamis included 4-foot waves that reached the US West Coast.

[Related: From the archives: A 1930s adventure inside an active volcano]

For the second paper, researchers in Japan used mathematical simulations to probe how Lamb waves produced by the eruption could have influenced the ensuing tsunamis. The team drew upon data from barometers, seafloor pressure sensors (which detect tsunamis passing overhead), and global coastal tide gauges in their analysis.

The leading waves were recorded moving at speeds of about 300 meters per second (671 miles per hour). They were followed by waves traveling about 200 to 220 meters per second (447 to 492 miles per hour), which matched typical speeds expected of tsunamis associated with earthquakes, said Tatsuya Kubota, a seismologist at the National Research Institute for Earth Science and Disaster Resilience in Tsukuba, Japan. These disturbances lasted more than three days, which is much longer than earthquake-related tsunamis.

Kubota and his collaborators found that the Lamb wave drove the leading surge of water, while the topographic features of the Pacific seafloor scattered these waves to produce subsequent long-lasting tsunamis. The characteristics of volcanic tsunamis make them more complex and challenging to forecast than earthquake-induced tsunamis, the team concluded.

“One important implication is, I think, [that] we need to incorporate the knowledge of volcanology and meteorology into tsunami science,” Kubota said in an email. 

Rolland noted that her team’s work also suggests that the fast-moving Lamb wave pulse contributed to the unusual tsunamis.

“In absence of correct knowledge on the source, the operational tsunami early-warning systems provided inaccurate estimates of the tsunami threat,” she said in an email. “It is thus paramount to understand the underlying physical mechanisms and to fully explain those peculiar observations and get early-warning systems procedures adapted to the case of explosive volcano eruptions.”

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As the US passes 1 million fatalities from COVID-19, a new analysis from the World Health Organization reveals how dramatically governments have undercounted deaths related to the pandemic.

The agency announced on May 5 that the pandemic claimed approximately 14.9 million lives in its first two years—more than twice the number of confirmed deaths reported by countries around the world. The WHO estimate includes people who died of COVID-19 as well as deaths that the novel coronavirus caused indirectly. 

Data on COVID-19 fatalities is tricky to make sense of, both in the US and globally. However, accounting for these deaths is important to gauge the full impact of the pandemic, experts say. 

“Understanding mortality is so critical,” says Albert Ko, an infectious disease physician and epidemiologist at the Yale School of Public Health. “Having these numbers will be important for decision makers to know how many lives could be saved in the future.” 

Analyzing mortality data reveals which groups are most at risk from COVID-19 due to their age, health status, race, or other characteristics. This information can help policymakers and public health organizations determine how best to protect vulnerable populations going forward. Mortality rates in different states or countries can also reveal the ability of control measures or vaccination campaigns to avert deaths.

There are several ways to measure the pandemic’s death toll. One is the number of deaths reported to national organizations such as the Centers for Disease Control and Prevention. This approach has a few drawbacks. Deaths tend to be undercounted in areas where COVID-19 tests aren’t widely available or health infrastructure is limited. 

“Those places that have the weaker surveillance or reporting systems are likely also the places that may have the highest death rates,” Ko says. And it’s often difficult to figure out “who actually died of COVID, versus those people who may have died of cancer or heart disease or trauma but were infected at the same time,” he adds.

Some governments are also more forthcoming with COVID-19 mortality data than others. Aleksei Raksha, a demographer who quit Russia’s state statistics service, recently told the New York Times that COVID-19 was frequently omitted as the primary cause of death in official reports.

[Related: The 5 phases of COVID’s endgame]

Another challenge is that the criteria used to define COVID-19 deaths isn’t necessarily consistent from one location to the next, says Justin Lessler, an epidemiologist at the University of North Carolina Gillings School of Global Public Health. It can even change over time; Massachusetts initially counted all deaths that occured after a positive test as COVID-related, but has since narrowed its criteria. 

“That presents challenges in the sense that you’re not making apples-to-apples comparisons when you’re looking across various jurisdictions and areas,” Lessler says.

Unlike Britain, which can rely on its National Health Service, the US and other countries that lack centralized healthcare systems face additional difficulties. “The fragmentation of information has certainly been a challenge in the United States,” Ko says. 

In such patchwork systems, death counts can jump quite a bit from one week to the next as some jurisdictions lag behind others in reporting data. “You can generally assume if there’s a two- or threefold increase in how many deaths are reported on a given day that it’s probably not the result of a lot of people dying then,” Lessler says. “It probably has something to do with reporting.” 

A more reliable way to assess COVID-19 deaths is a metric called “excess mortality.” Based on records from past years, researchers calculate how many people would be expected to die in a given time and place. The difference between the total number of deaths that occurred and this estimate is the excess mortality. Scientists often use this approach to understand the full impact of crises, including diseases and disasters such as Hurricane Maria.

In its new report, the WHO used excess mortality to conclude that nearly 15 million people died worldwide because of the pandemic in 2020 and 2021. Another excess mortality estimate published in March by an international team of researchers in the Lancet put the number of deaths even higher—at 18.2 million. 

Excess mortality doesn’t just capture fatal COVID-19 cases. It also includes deaths that occurred because hospitals became overwhelmed, or because people were afraid to seek treatment for other issues or schedule routine screenings. Furthermore, the estimates account for deaths that COVID-19 prevented. The early pandemic’s containment measures resulted in fewer traffic accidents and decreased the transmission of other diseases such as influenza. 

The WHO found that 84 percent of the fatalities came from Southeast Asia, Europe, and the Americas, with the US among the top five countries with the most excess deaths. For places with sparse mortality data, the agency used other measures such as the country’s COVID-19 containment efforts and population demographics to estimate excess deaths.  

Researchers will continue to fine-tune their estimates of the pandemic’s death toll. A century after the 1918 flu pandemic, Lessler notes, scientists are still attempting to unravel the mystery of how many people actually died. “We have much better data and much better information to go on now, and there aren’t going to be the same massive uncertainties for this pandemic as for that one,” he says. “[But] I think there will be debates and accountings and attempts to understand it for years to come.” 

However, Lessler and Ko predict, the message conveyed by the excess mortality estimates is unlikely to change.

“The bottom line is the number of people who died because of either direct or indirect effects of COVID is much larger than what was counted by reported deaths,” Ko says.

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Last week the US Food and Drug Administration announced its intention to ban menthol cigarettes and all flavors in cigars.

“The proposed rules would help prevent children from becoming the next generation of smokers and help adult smokers quit,” Health and Human Services Secretary Xavier Becerra said in the FDA’s April 28 statement. “Additionally, the proposed rules represent an important step to advance health equity by significantly reducing tobacco-related health disparities.” 

Menthol is used in cigarettes as a characterizing flavor (that is, readily detectable) with a subtle minty taste, and has a cooling effect that manufacturers say soothes the throat from irritating smoke. By eliminating this chemical compound and more palatable flavor, the agency hopes to make smoking less attractive to young people and encourage current smokers to consume fewer cigarettes or quit entirely.

This falls in line with a larger crackdown on various types of cigarettes: The FDA recently expanded its authority to cover synthetic nicotine in electronic cigarettes, forcing manufacturers to comply with the same standards as other products that contain tobacco-based nicotine.

The menthol ban in particular would represent one of the biggest FDA shake ups on cigarettes since the 1960s.

“I see no downside to eliminating menthol from cigarettes,” says Vaughan Rees, director of the Center for Global Tobacco Control at the Harvard T.H. Chan School of Public Health. “I think the US is finally coming to grips with this long-standing issue, and I sincerely hope that the FDA takes decisive action on it.”

[Related: E-cigarettes could help you quit smoking—and help your kids start]

Decades of aggressive marketing of menthol cigarettes has led to “grievous health disparities and hundreds of thousands of avoidable deaths” among Black Americans and other historically marginalized groups such as sexual and gender minorities, Daniel Giovenco, assistant professor of sociomedical sciences at the Columbia University Mailman School of Public Health, said in an email. 

“If implemented appropriately, this ban will be a massive victory for public health and health equity,” Giovenco said. “Eliminating this product from the marketplace is a major step in reducing the unequal burden of disease and death caused by tobacco products.”

What the science says about menthol

Menthol was first added to cigarettes in the 1920s and marketed (inaccurately) as a healthier and safer alternative.

Menthol is a compound naturally found in plants, like peppermint, and  produces a cooling sensation—it’s often what makes your toothpaste or spearmint gum taste and feel minty fresh. But unlike those safe products, menthol in cigarettes can mask more dangerous chemicals. Menthol makes the smoke feel smoother on the throat, opens the airways, and has mild anesthetic properties, says Rees. “Mentholation not only makes it easier to smoke, it encourages deeper inhalation and therefore greater exposure to the toxic constituents that are present in tobacco smoke,” he says. 

There are more than 7,000 chemicals in tobacco smoke, hundreds of which can cause cancer or are otherwise harmful. These toxic compounds can damage the cardiovascular system, kidneys, brain, respiratory system, and more, says Judith T. Zelikoff, a professor of environmental medicine at the NYU Grossman School of Medicine. “So you’re not just getting the menthol in cigarettes,” she says. 

Additionally, menthol interacts with nicotine in the brain to boost its addictive effects, the FDA says. For all of these reasons, it argues, menthol increases the risk that young people who start smoking will become hooked. 

“There’s a need for making more people aware of the likelihood of menthol playing a role in illnesses and disease,” Zelikoff says. “If you keep menthol in, the more you’re going to smoke; the more you’re going to smoke, the more people are going to continue to die.”

There were more than 18.5 million menthol cigarette smokers aged 12 and older in the United States as of 2019, which include a disproportionate share of teens and young adults, Black Americans, and other racial and ethnic minorities. According to one estimate, banning menthol cigarettes and cigars in the US would lead to a 15 percent reduction in smoking and prevent roughly 650,000 deaths by 2060. 

A number of countries have already banned menthol, including Canada in 2017. Researchers found that these restrictions caused 59.1 percent of surveyed smokers to switch to non-menthol cigarettes and 21.5 percent to quit smoking (an additional 19.5 percent still smoked menthols purchased from First Nations reserves).

“The movement is in the direction that we would hope for, which is reduced consumption or increased cessation,” Rees says.

A decision “decades in the making”

Advertisements for menthol cigarettes have long targeted Black Americans, about 85 percent of whom prefer menthol cigarettes.

Opponents of the menthol ban have said that it would put a disproportionate burden on Black smokers and increase policing of Black neighborhoods. However, the FDA emphasized that the new regulations won’t make it illegal for individual consumers to possess or use menthol cigarettes and flavored cigars.

“If these proposed rules are finalized and implemented, FDA enforcement will only address manufacturers, distributors, wholesalers, importers and retailers who manufacture, distribute, or sell such products within the US that are not in compliance with applicable requirements,” the agency wrote. 

African Americans smoke at similar rates to the general population but face more serious health consequences. “Main probable causes for this phenomenon are the high overall mortality rates due to economic and social conditions and the high prevalence of menthol among African American smokers, which causes them to be more addicted and quit less,” health policy researchers at the University of Michigan noted in a 2021 report in the journal Tobacco Control.

A number of public health groups, including the African American Tobacco Control Leadership Council and the National Medical Association (the country’s oldest organization representing African American physicians) say that the regulation is a crucial and long-awaited step. They joined with several other organizations, including Action on Smoking and Health and the American Medical Association, to petition the FDA to ban menthol-flavored cigarettes in 2013 and sued the agency in 2020, ultimately spurring the proposed new restrictions.

The menthol ban is a historic move “decades in the making,” Phillip Gardiner, co-chair of the African American Tobacco Control Leadership Council, said in a recent webinar hosted by the plaintiffs. “The bottom line is that menthol cigarettes and flavored little cigars have been and are the main vectors of death and disease into the Black community,” he said. 

[Related: Teens who experience racism are way more likely to smoke]

Menthol cigarettes account for about a third of the $80 billion cigarette market in the US. Banning them would represent a huge win for tobacco control activists, Rees says. This would stand alongside other momentous decisions such as the Public Health Cigarette Smoking Act of 1970, which forbade cigarette ads airing on television and radio; the 1998 Master Settlement Agreement, which was the largest civil litigation settlement in US history and restricted tobacco advertising aimed at youth; and the FDA gaining regulatory control over tobacco in 2009.

It will take time to fully remove menthol cigarettes from the market, Gardiner said in the presentation, noting that the FDA’s proposal would allow menthol cigarettes to be sold for a year after its final publication. “The tobacco industry will try and drag this out as long as it can,” he predicts, describing the proposed regulations as “just the beginning of the end.”

Taking aim at other tobacco products

In 2009 the Family Smoking Prevention and Tobacco Control Act prohibited all characterizing flavors other than tobacco and menthol in cigarettes. However, until now flavors such as strawberry and cocoa have still been permitted in cigars.

Like menthol, the FDA says, these flavors make tobacco products easier to smoke and banning them will cut down on the number of young people who become regular smokers. This element of the FDA’s announcement has been “somewhat overlooked,” Giovenco said, but is vital given that cigars now rival cigarettes in popularity among teenagers and carry similar health risks.

The government’s 2021 National Youth Tobacco Survey of middle and high school students found that an estimated 1.5 percent smoked cigarettes and 1.4 percent smoked cigars. Of those cigar smokers, 44.4 percent reported using flavored cigars. 

However, by far the most popular tobacco products among the surveyed youth were e-cigarettes, which were used by 7.6 percent.

The national spending bill enacted on March 15 included legislation that might address the rise in young e-cigarette users. Congress granted the FDA oversight over all nicotine products, whether derived from tobacco plants or made in a laboratory. This rule, which took effect on April 14, closed a loophole that e-cigarette companies have used to avoid regulations intended to curb vaping among young people, and would require manufacturers to seek the FDA’s permission to sell synthetic nicotine products.

[Related: A ban on flavored vaping products could help signal to teens that vaping isn’t as safe as they think]

It will be critical to balance efforts to prevent vaping among adolescents with the necessity of helping adult smokers quit, Rees says. “E-cigarettes represent an important tool to help adult smokers reduce their health risks arising from smoking, and increase their chance of long term cessation,” he wrote in a followup email. 

In a March announcement authorizing several tobacco-flavored e-cigarette devices, the FDA stressed that all tobacco products are harmful and potentially addictive.

“We are making progress in our review of flavored ENDS [electronic nicotine delivery systems], and we will continue to deny marketing of products where the applicant hasn’t provided enough evidence to show that the potential benefit to adult smokers outweighs the considerable risk to youth,” Mitch Zeller, director of the FDA’s Center for Tobacco Products, said in the statement. 

Next steps

The FDA is accepting public comments on its proposed rules for menthol cigarettes and flavored cigars through July 5, after which the agency will decide on its final standards. 

Once the ban is implemented, Giovenco said, public health organizations and healthcare providers must be prepared to help people quit so they don’t merely switch to non-menthol cigarettes. 

“Whenever a new policy restricts or prohibits an addictive product, it’s important to simultaneously expand resources that provide people with a viable ‘off ramp,’” he said. “This could include increasing access to quit services, counseling, and nicotine replacement therapies.” 

Menthol is just one of many features that manufacturers use to make cigarettes more appealing, Rees says. “If menthol goes away, there’s a likelihood that tobacco manufacturers are going to resort to other workarounds to continue to make cigarettes easy to inhale, mislead smokers about the potential health risks, and reduce the harshness in and the heat from tobacco smoke,” he says. “So bans on filtered ventilation and bans on other additives that change the smoothness and harshness should also be considered in conjunction with a ban on mentholation.”

Another important goal, Gardiner noted, will be eliminating menthol from other products such as e-cigarettes and as a less conspicuous ingredient in cigarettes. “Getting rid of it as a characterizing flavor is just step one in a process of getting rid of it altogether,” he said.  

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Small patches of tropical reefs that endure despite punishing marine heat waves could hold clues to protecting the world’s corals, a new analysis suggests.

Scientists took aerial surveys of Hawaiian reefs before and after a major heat wave in 2019, and found that corals at certain sites fared better than their neighbors. These so-called refugia lost up to 40 percent fewer corals despite facing similar temperatures. A number of variables may explain their success, including distance from human settlements, the researchers reported on May 2 in Proceedings of the National Academy of Sciences.

“We’re trying to understand where those [refugia] are and why they’re there,” says Greg Asner, a coauthor of the study and director of the Arizona State University Center for Global Discovery and Conservation Science in Hilo, Hawaii. “From a conservation point of view, these are tiny points of light, like little arks of biodiversity that are already in the ocean that need protection.”

Climate change has made heat waves more common in the sea. Prolonged exposure to these toasty conditions poses a serious threat to corals. When the surrounding water becomes too warm, the stressed-out corals undergo bleaching: The beneficial microscopic algae that  dwell within the corals are expelled, leaving them a ghostly white color. If the heat wave continues long enough, the corals will ultimately die. 

To better understand why some corals are more resilient than others, Asner and his collaborators tracked coral mortality over 21,773 hectares (84 square miles) of reefs surrounding six Hawaiian Islands. The researchers flew over the reefs in January 2019, six months before a marine heat wave descended on the archipelago. The team then repeated the survey in January 2020 to find out how the corals had weathered the disturbance. 

The researchers used a technique called imaging spectroscopy to analyze the molecular composition of the corals, which allowed them to distinguish living corals from deceased ones. The proteins, chlorophyll, and carbon compounds measured in living corals and their algal denizens are distinctive, Asner says. Once the coral dies, it becomes covered by macroalgae, which have a molecular composition more akin to terrestrial plants. 

Most previous studies have focused on bleached corals, Asner says. However, not all of these ailing corals will perish. “The thing we really need is to know where the corals are dying, not just getting sick, so that we can start to formulate conservation and management planning around those who die and those who survive,” he says.

After the heat wave, the reefs Asner and his team mapped lost an average of 26.1 percent of their live corals, covering about 6.3 percent of the seafloor. The waters surrounding the islands of Lanai, Hawaii, and Kahoolawe, which were hit particularly hard by the marine heat wave, lost the greatest proportion of live corals. 

However, the researchers also found that reefs with more abundant coral cover before the heat wave withstood the event better than reefs with sparser coral cover. These zones might be acting as long-term refugia during heat waves, the team wrote. There were several dozen havens that ranged in size from a few acres to several hundred acres, Asner says.

“The good scenarios were mostly in the undeveloped areas with very little pollution and sedimentation or runoff,” he says. These corals were likely healthier when the heat wave struck than those in reefs near residential and agricultural areas. 

“Wastewater treatment in Hawaii is really bad,” Asner says. “We have a lot of human effluent—poop and pee—going into the ocean in certain areas.” Stemming the flow of human waste, pesticides, and other pollutants will be crucial to fortify corals that don’t live in sheltered refugia, he says. 

Additionally, some refugia were located near natural underwater springs fed by cool, fresh groundwater. “In areas where that [freshwater] leaked out, corals did better during the heat wave because it’s like a little thermal blanket,” Asner says. However, he adds, more research is needed on how important these “little protectors” are, and how well they will stand up to increasingly intense marine heat waves in the future.

Even within the refugia, not all corals survived. “There were clearly winners and losers,” Asner says. Some species, such as cauliflower coral, are more vulnerable to rising temperatures than others. And some corals have genetic traits that make them hardier than other members of their species. Tracking which corals within a refugium survive heat waves can give conservationists valuable information for coral breeding and reef restoration efforts, the researchers concluded.

[Related: Coral reefs are dying, but it’s not too late to save them]

Another important next step is to identify refugia in reefs beyond the Hawaiian Islands. How corals in a given area react to rising temperatures will depend on their local oceanic environment, which species are present, and what kinds of pollution and other stressors the reef is facing. Asner and his team hope to begin measuring coral mortality using satellites next summer.

“We’re going to get the global coverage done in this decade, or even in the first half of this decade, but right now I don’t want people to think that Hawaii represents the entire planet,” he says.

The new results echo some patterns that scientists have noted in previous aerial surveys of the Great Barrier Reef, says Terry Hughes, a marine biologist at the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University in Townsville. 

“We also showed that heat exposure…explains why some places lose more corals than others,” Hughes said in an email. “More corals die where the water is hottest the longest, in each bleaching event.” 

His team additionally found that some coral species died at higher rates than others, although these disparities shrank under more extreme conditions. “The winner-loser spectrum is most prominent when bleaching is comparatively mild,” Hughes said. “Even the so-called winners have high losses if the temperatures are high enough.”

Hughes and his colleagues have also tracked coral bleaching on the Great Barrier Reef after repeated heat waves. Parts of the northern reef escaped bleaching in 1998 and 2002. “Then the north fried in the third mass bleaching event in 2016, and has since bleached again in 2017, 2020 and 2022,” Hughes said. “To identify a refuge, you need to look at its responses to heat stress in multiple bleaching events, to see if that location consistently escapes with little or no damage.”

He cautions that it remains to be seen how the newly-discovered refugia in Hawaii will handle future disruptions.

“It’s premature to regard a location with comparatively smaller losses in one year as a refuge,” Hughes said. “The world is full of former coral reef refuges—places that were comparatively lucky in one bleaching event, only to be hammered in a subsequent one.”

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When out for a jog, people automatically settle into energy-efficient running speeds regardless of how far they’re going, scientists reported this week. 

A group of biomechanists analyzed measurements from people running on treadmills as well as wearable data from thousands of recreational runners, and concluded that humans have a preferred speed that minimizes calories burned. 

“A lot of people’s assumption, including our’s going into it, would be that you choose a faster pace when you’re going to run a shorter distance and then slow that pace when you’re going to travel a longer distance,” says Jessica Selinger, a biomechanist at Queen’s University in Kingston, Ontario and coauthor of the findings. “What we found is that an individual’s running speed is really consistent regardless of the distance that they’re running.”

The findings have relevance for athletes, anthropologists, and rehabilitation specialists, she and her collaborators reported on April 28 in Current Biology. 

“This research suggests that the drive to minimize energy costs is really strong in humans, even when we’re purposefully exercising as a way to expend more energy,” says ​​David Raichlen, an evolutionary biologist who studies exercise at the University of Southern California and who wasn’t involved in the study. “We have a hard time overriding that desire to use as little energy as possible in any given task.”

[Related: Running might be kind of contagious]

Previous studies have shown that in competitive races, where the goal is to cross the finish line as quickly as possible, humans adopt brisk paces for shorter distances and more moderate paces for longer ones. But it wasn’t clear if this pattern also applied to joggers under more relaxed conditions.

To find out, Selinger and her colleagues analyzed data from 4,645 real-world joggers who collectively took 37,201 runs that ranged from 1.6 to 11.3 kilometers (1 to 7 miles) while wearing fitness trackers. They found that the real-world joggers generally kept to the same speed regardless of how far they ran. Only over distances greater than 10 kilometers (6.2 miles) did the runners slow slightly, likely due to fatigue kicking in.  

The researchers also tracked how much energy 26 college students burned while running at different speeds on a treadmill. The team then compared these participants with recreational joggers from their database of similar age, sex, and body mass index (BMI) whose runs covered relatively flat terrain. It turned out that the speeds that were most energy-efficient for the treadmill runners matched the preferred speeds of the real-world joggers.

“For a lot of folks it’s the [pace] that’s going to feel quite comfortable and that we have this natural tendency to slip back into,” Selinger says. “It’s certainly the case that you can and do run faster in other settings; if you’re in a race, you’re going to push yourself beyond that energy-optimal gait.”

This optimal speed varies depending on characteristics such as weight or sex; the most energy-efficient speed was on average 2.65 meters per second (8.7 feet per second) for females and 3.35 meters per second (11 feet per second) for males. (The researchers inferred the sex of study participants in the wearables group from self-reported user identification in the device’s app). However, these estimates probably aren’t broadly representative, Selinger cautions. The energetic data she and her colleagues gathered came from healthy young adults who were athletic but not elite runners. Measuring participants from a wider range of ages, fitness levels, and other demographics could help the team build a more complete picture. 

The researchers additionally plan to investigate how training and environmental conditions such as the weather affect a person’s energy-optimal running speed. Future studies could also track participants during routine jogs as well as on the treadmill, Raichlen adds. “It would be nice to see more direct matching of individuals with their energy costs,” he says.

Whether walking, galloping, flying, or swimming, animals generally stick to the most efficient speed for their bodies, says Jennifer Hicks, a biomechanist at Stanford University and another coauthor of the report. The new findings indicate that humans share this trait. “From an evolutionary perspective, moving in the way that’s most energy efficient makes a lot of sense in that we can travel farther with less fuel,” she says.

The results may also have practical applications for exercise scientists, rehabilitation specialists, coaches, and sports medicine practitioners. “Understanding what drives people to move the way that they do is a really important first principle before we start thinking about training people to move in other ways, or adding assistive devices to their body that are going to change how they move,” Selinger says.

It’s possible that designs for fitness trackers or running shoes could be improved by taking into account people’s most efficient running speeds. “Can we design a shoe that will shift someone’s energy from that pace to a slightly different speed so that becomes their new natural speed?” Hicks says.

[Related: Why do marathon runners get the runs?]

For recreational runners looking to spend more energy, she says, listening to music or running with other people are great ways to change up your running speed. “If burning calories is the goal of your run, running a little faster than your natural tendency or even a little slower is the pace that may make sense,” Hicks says. 

Selinger adds that even though you burn fewer calories when you are running slower, it’s going to take you much more time to get to your destination—so overall, you end up burning more calories. That is, you’re going to burn more calories running a mile very slowly than you are running that mile at your most efficient speed. In this way, Selinger says, our bodies are similar to a car that must cover a set distance. “You would burn more fuel if you just idled and barely moved and it took you hours to get from point A to point B, and you would also burn more fuel if you put the pedal to the metal and went as fast as you can,” she says. “There’s an optimal speed you can travel your car at to burn the least amount of fuel, and the same is true for the runner.”

But all that said, running and other forms of exercise offer many advantages aside from burning calories, such as strengthening muscles and lowering the risk of cardiovascular disease.

“I wouldn’t want folks to get too hung up on the calorie-burning aspect of it,” Hicks says. “Running at your preferred, energy-optimal speed is also a great choice to get the benefits to mental health and protection against disease that physical activity has.”

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Having sturdy jaws is essential for the small marine creatures known as bloodworms. 

The worms, which grow to about 15 inches in length, spend their lives burrowing through the muddy seafloor and hunting small crustaceans, molluscs, and other worms. 

“They need their jaws to kill the more active prey,” says Herbert Waite, a marine biochemist at the University of California, Santa Barbara. “They also use the jaws to fight each other off because they’re not very sociable, and occasionally the worms will collide in the burrows.”

The jaws must be both very sharp and very tough because bloodworms only make them once during their lifetimes, Waite says. The key to this fearsome maw lies in a unique mix of copper, melanin, and a protein with some impressive chemical properties, he and his collaborators reported on April 25 in the journal Matter. The worms’ efficient jaw-building process may hold insights for improving how composite materials—which are made from a mix of different substances—are manufactured, the team concluded. 

Each bloodworm sports a proboscis with four black jaws to grasp other animals and inject them with paralyzing venom. These hollow fangs are lightweight but can withstand a lot of wear and tear thanks to their melanin and copper components, Waite and his colleagues wrote in the new paper. These are unusual ingredients for animal jaws. Copper is “usually quite toxic” to animals, Waite says, and melanin is a pigment that rarely serves as a structural element.

“We’ve had an interest in how different marine invertebrates make load-bearing structures for survival, and this one stood out in particular because it was one of the only ones reported to have high copper content,” he says. 

Scientists aren’t sure why the worms opted for copper rather than another metal more typically used by marine invertebrates, such as iron or zinc. However, one possibility is that the copper reacts with the venom stored in the fangs. “The worm has the luxury of storing these toxins in some kind of less harmful or inert form and they become toxic as they move through the channels in the jaw on their way into the prey,” Waite says.

[Related: Surprise: Ants have teeth. Here’s how they keep them sharp.]

To investigate how bloodworms put their distinctive fangs together, Waite and his team identified the genetic sequence that codes for the main protein in the jaws. They found that the protein’s chemical composition was fairly simple, with about 80 percent represented by two amino acids. The team then made an artificial version of the molecule, which they named “multi-tasking protein,” in the lab. 

Next the researchers performed a simplified version of the jaw formation process. They added copper to the beakers with their artificial multi-tasking protein and observed that the two materials become concentrated into little droplets. When the researchers added a molecule called Dopa (which other animals often convert into melanin), the droplets turned darker and formed a dense film. 

“We noticed that if you put a pin tip into the brownish-black film that formed on the surface you could actually pull fibers out of that film and then test them mechanically,” Waite says. “It turned out that the fibers resemble nylon, and that’s a pretty strong fiber.” 

The experiment indicates that a single protein plays multiple vital roles in bloodworm jaw formation: binding to copper, concentrating itself into droplets, converting Dopa to melanin, and ultimately forming a composite material. This is much simpler than what must take place to form industrial composites such as fiberglass or reinforced rubber.  

[Related: This cone snail’s deadly venom could hold the key to better pain meds]

“What the worm is doing to form its jaws gives us a kind of blueprint for how composite materials can be made more sustainably and less reliant on heavy equipment, for example, mixers, blenders, extruders,” Waite says. “Certainly those don’t exist in the bloodworm system and yet a very organized material is forming.”

The chemical reactions that bloodworms use to make their fangs are very sensitive to the acidity, salinity, and temperature of the surrounding seawater. This could mean that bloodworms are vulnerable to the effects of climate change, Waite says. 

Still, the bloodworms’ natural knack of creating tough materials offers a valuable lesson, says Waite. With their remarkable jaw-formation process, Waite sees similarities in some respects to the giant sandworms that populate the Dune novels.

“These worms that lived in a wasteland produced something called spice that everyone in the universe wanted,” Waite says. “It’s been a reminder, in an exaggerated way, that simple organisms can harbor really useful technologies.”

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Sexually transmitted infections have been on the rise in the United States for some time. In 2019, the country reached an all-time high for the sixth year in a row. Then COVID-19 struck and healthcare across the US was profoundly disrupted.

A report released this month by the Centers for Disease Control and Prevention highlights that STI rates remained alarmingly high in 2020, with reported cases of some infections continuing to climb. 

“We already had a strained, crumbling public health infrastructure. There are many communities in the United States that do not have STI specialty clinics,” Jonathan Mermin, a senior official with the CDC, said in a call with reporters. “What that led to was an exacerbation of the already increasing trends.”

The pandemic may have worsened the STI epidemic, experts say, but it also forced health professionals to start thinking of better ways to combat this issue. In particular, at-home testing for STIs shows promise as a strategy for getting more people screened. 

Troubling trends

Much of the brunt of STI prevention and treatment efforts has fallen on public health agencies that are chronically underfunded and understaffed, says Amesh Adalja, an infectious disease physician and senior scholar at the Johns Hopkins Center for Health Security.

“And when the pandemic occurred many public health agencies had to completely shift on a dime and focus exclusively on COVID-19,” he says. “So that meant pulling resources that might have been used for [sexually transmitted disease] screening, STD testing and STD clinics and moving all those personnel to COVID-19.” 

At the same time, Adalja says, many primary care doctors weren’t doing routine physical examinations—where STI counseling and screening often occurs—or were limiting in-person visits. Additionally, many people lost their jobs and health insurance or put off checkups. The new CDC report indicates that all of these circumstances may have made it easier for STIs to have spread while being diagnosed and treated less.  

[Related: America’s sexually transmitted disease rates are out of control]

In 2019, there were 2.5 million cases of chlamydia, gonorrhea, and syphilis reported in the US. The following year, 2.4 million cases of these common STIs were reported. From 2019 to 2020, reported chlamydia cases actually dropped by 13 percent. However, the CDC report emphasizes, that’s probably not because there were fewer new infections; chlamydia is frequently asymptomatic, and the decline in reports likely happened because fewer people were getting screened. 

Meanwhile, reports of gonorrhea and early-stage syphilis decreased during lockdowns but then surged 10 percent and 7 percent, respectively, past 2019 levels by the end of the year. Congenital syphilis, which can cause serious health problems and even death in babies, also increased in 2020.

For reported gonorrhea and syphilis to increase in spite of reduced STI screening is especially concerning, says Matthew Golden, an infectious diseases specialist and professor of medicine at the University of Washington School of Medicine. He suspects that the true incidence of these infections is being underestimated. 

“If we’re doing less screening and we’re not identifying those asymptomatic cases, then they have a longer opportunity to transmit,” Golden says. 

The unabated rise in congenital syphilis cases indicates that more work is needed to target people who are pregnant or could become so, he says. Additionally, he says, more testing is needed for populations at elevated risk of STIs, including people who are homeless, use injected drugs, incarcerated, or sex workers will be necessary.

While COVID-19 didn’t improve matters, rising rates of gonorrhea and syphilis are “just one more facet” of a broader problem, he adds. “At some important level these are a consequence of our epidemics of homeless and substance use,” Golden says. “And these are not problems that we’ve been very effective in dealing with.”

Just because the novel coronavirus became the top priority of federal, state, and local governments, it didn’t mean that other infectious diseases such as STIs disappeared, Adalja says. “They don’t take a break when COVID-19 is occurring,” he says. “The STIs didn’t say, ‘Okay we’ll wait until you come back.’”

What can be done

It may be some time before we know the full impact of the COVID-19 pandemic on STI rates. The extent to which delays in diagnosis and treatment contribute to complications such as pelvic inflammatory disease and infertility also remain to be seen, the CDC concluded in its report. 

“We must prioritize on-the ground support for STD prevention and surveillance programs through disease investigation, contact tracing, training, partnerships, and community engagement,” the agency wrote. 

In March, Congress decided to allocate less funding than in previous years for sexual health clinics that provide services such as free and subsidized STI testing. However, the pandemic and its damaging effects on STI prevention and control efforts highlight how important it is to consistently invest in public health services, Adalja says. Going forward, he adds, it’s crucial for voters to make it clear to their elected officials that sexually transmitted infections are an issue they care about, much as HIV activists have done in the past.

“STD funding is not very politically interesting for them; we have kind of a puritanical culture so they don’t want to talk about that stuff, it’s not something to brag about when they do well on it,” Adalja says. “If you say ‘I’m going to vote based on your position on our county health department,’ then they’ll start to care about it.”

Another strategy for tackling rising STI rates that’s growing in popularity is tests that can be taken at home. During an at-home test, a person typically collects blood, urine, or other samples on their own and mails them off for analysis. One advantage of this approach is that it allows people who aren’t comfortable visiting a doctor or clinic, particularly if they’ve faced discrimination in the past, to get tested.  

“For communities that don’t fit into the normal mold—be it sexuality, be it race, be it gender identity—there’s a way smaller barrier to accessing care in that you don’t have to explain who you are, the way you have sex, who you have sex with,” says David Stein, the CEO and cofounder of the at-home diagnostics startup Ash Wellness. “In in-person, real-life environments that can be a huge barrier to care and a reason people don’t even seek it out.”

[Related: Insurance coverage for at-home tests could help stop the rise in STIs]

Stein adds that it’s important to confront the lingering stigma around sexually transmitted infections to move forward. “STIs are normal…but the only way to prevent epidemics like this and the HIV epidemic is to have testing campaigns and the ability to find follow-up care and treatments,” he says.

At-home testing may help “decongest” an overburdened healthcare system, Golden says. It also offers convenience, especially for people who can’t afford to take time off work to get tested. 

On the other hand, this approach doesn’t work as well for people who don’t have stable housing or consistent internet access. For this reason, increasing STI testing programs at sites such as prisons, emergency rooms, and methadone clinics will remain important, Golden says.

Another key question is when and how frequently insurance companies will pay for home testing. “That is one of the biggest barriers,” Stein acknowledges. However, he says, “We’re finally getting to a point where self-testing is the norm, partly popularized by at-home self-testing for COVID.”

We’ve already begun to see this play out. California recently became the first state to require insurance plans to cover at-home STI tests. “COVID-19 testing at home has opened up an opportunity to really examine home testing policies and make it much easier to have this happen,” says Adalja. 

In addition to the convenience and comfort of taking a COVID-19 self test at home, they deliver almost immediate results without the need for laboratory analysis. This is also the case for an FDA-approved rapid self-test for HIV. There’s no technological barrier to developing rapid tests for STIs as well as other diseases, says Adalja, who coauthored a 2020 report on the potential of self-testing for any disease. 

“For COVID, people do a rapid test before they might be going to a high-risk event or being around an immunocompromised person,” he says. “You could use STI screening at home that way as well.”

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Cases of cannabis poisoning in pets have risen significantly over the past few years, a survey of veterinarians in Canada and the United States indicates.

Researchers asked 251 vets about the frequency, circumstances, and symptoms of cannabis poisoning (also known as cannabis-induced toxicosis) they’d observed since Canada legalized recreational weed in 2018. The team found that the most common victims of cannabis poisoning were dogs, and edibles were the most commonly suspected cause. The afflicted animals often became very disoriented or lethargic and had abnormally slow heart rates, but most made a complete recovery, the researchers reported on April 20 in the journal PLoS ONE.

“[Cannabis toxicity] is becoming more common as things are now legalized,” says Jenica Haraschak, an emergency and critical care specialist at University of Illinois College of Veterinary Medicine, who wasn’t involved with the new research. “Now it’s out on the kitchen table and more available for pets to get into.” 

Veterinarians have been taking note of an increase in pet poisoning linked to cannabis, she adds, and the research team from Canada validate the trend with the new data. “It’s interesting that they finally published a study confirming what we all think has been going on,” she says. “It’s really helpful to put that out there and let people know about this problem.”

Canada started allowing adults to grow, buy, and use cannabis for recreational purposes in October 2018. In the United States, Colorado and Washington state were the first to legalize recreational weed in 2012, with 16 other states as well as Washington, D.C. having since followed suit. The American Society for the Prevention of Cruelty to Animals (ASPCA) has seen a rise in reports of cannabis poisoning in pets in recent years. But until this point, data about the magnitude of this problem have been sparse, says Jibran Khokhar, a neuroscientist at the Ontario Veterinary College at the University of Guelph and coauthor of the findings. 

“The real goal was to try to get a handle on what toxicosis looks like and how prevalent it is,” he says. “The biggest thing we got out of [the study] is a better understanding of what are the most commonly-seen symptoms across species.”

[Related: Can you overdose on weed?]

When he and his collaborators surveyed 191 veterinarians in Canada and 60 in the US, they observed that the amount of cannabis poisoning cases increased in both countries after fall 2018. While many respondents reported no difference in the number of cases they treated annually, nearly all who did notice a change said that cases had risen. 

One explanation for this shift is that the increased availability of cannabis products meant for people has led to more pets encountering the substance since legalization in 2018 in Canada (by then, some states in the US had also legalized weed). Some of the trend may also be due to pet owners being more forthcoming with vets after the drugs became legal, Khokhar says.

The veterinarians noted a wide variety of symptoms that ranged from very common (such as uncontrolled urination) to rare (including two cases of seizures). Animals with cannabis poisoning also frequently experienced disorientation, incoordination, lethargy, slow heart rates, twitching, and sensitivity to noise, light or smells. 

Generally, the animals recovered after being monitored or receiving treatments such as intravenous fluids or anti-vomiting medication. A handful of pets died, although it’s unclear whether the cannabis was directly responsible, Khokhar says, noting that the chocolate present in many edibles is also toxic to dogs and other pets. 

Although cannabis poisoning was most common in dogs, the veterinarians also treated cats, iguanas, ferrets, horses, and cockatoos. Pet owners frequently reported that their pets had gobbled up edibles while unattended. Another common source of exposure was fresh or dried plant material. A few cases involved discarded joint butts, human feces, cannabis-infused butters or oils, and compost. 

However, Khokhar cautions that these findings should be taken with a grain of salt. The data can contain flaws due to human error: Owners may have not remembered—or been willing to share—the full details of their pet’s exposure to cannabis. The veterinarians might also have forgotten aspects of past cannabis poisoning cases by the time they filled out the survey. 

“Everybody would say that [the cannabis was] from government-regulated products…or say it happened accidentally when they weren’t looking,” Khokhar says. “The reality is some of these animals may have been administered it by their owners, either for medicinal purposes or recreational purposes.”

[Related: Why you’re suddenly hearing about delta-8 THC]

THC (the main psychoactive component of cannabis) is likely responsible for sickening the animals. However, controlled doses of THC may ease pain, nausea, and other issues in pets, Khokhar says. More research is needed about the potential benefits of THC and CBD (the second most prevalent active ingredient in cannabis, which doesn’t produce a high) for animals. While there is a growing market of cannabis products aimed at pets, they currently aren’t approved or regulated in the U.S. or Canada.

“We don’t actually know the content of the CBD that’s in some of those products and we don’t know the full effect on the pets that are receiving it,” Haraschak says. “Until we have more information that says that it actually works and have regulations as far as how they’re made, it’s not ideal to have those pets on that.”

Khokhar and his colleagues plan to study how THC is metabolized in cats this summer. Additionally, the team is testing compounds that could potentially reverse cannabis induced-toxicosis. In the future, it would also be helpful for researchers to investigate what dosages are needed to cause life-threatening symptoms in animals, Haraschak says. Another question for further research is how other compounds—such as chocolate and xylitol (a common sweetener that is toxic to some pets)—found in edibles may affect cannabis poisoning.

Khokhar hopes the new report will raise awareness among pet owners about cannabis poisoning. While it’s important to keep cannabis-containing treats well out of reach of curious pets, accidents happen and there’s always the possibility that your pet will discover and snarf down a stray joint while out for a walk. 

With the new study, “at least now you know what to look for,” Khokhar says. “If you are seeing some of these symptoms in your pet, you should take them in [to the vet] and ensure that they receive the care that they need.”

Haraschak emphasizes that it’s crucial to provide your veterinarian with all the details of the incident if your pet is showing signs of cannabis poisoning.

“​​We don’t call the police or report anybody, especially with it being legal now; that part is not our concern,” Haraschak says. “There’s other diseases that could look similar to marijuana toxicity, and those are diseases that could be more severe or more costly. So having that information up front is very helpful from our standpoint to be able to provide the pet with the best care.”

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This winter, demand for COVID-19 treatments outstripped supply in many areas as the Omicron variant brought cases to record-high levels in the United States. 

As this surge has ebbed, medications to combat COVID-19 have become more accessible. One particularly promising treatment is Pfizer’s Paxlovid, which has received emergency use authorization in COVID-19 patients aged 12 years and older who weigh at least 88 pounds and are especially vulnerable to developing severe COVID-19. In clinical trials, the antiviral pill was nearly 90 percent effective at protecting unvaccinated people at high risk of severe COVID-19 from hospitalization and death if given soon after symptoms started. 

“The fact that we have a drug that does that is really remarkable,” says Scott Roberts, the associate medical director of infection prevention at the Yale School of Medicine. “We’ve seen supply go up and most patients who do qualify for this are able to receive it.”

Paxlovid has several advantages over other COVID-19 treatments, but has a key drawback: it interacts with a number of other medications, including some antidepressants, heart medicines, and hormonal birth control. However, these complications can often be avoided by adjusting the dosage of the other drugs, Roberts says. 

Drug interactions

The most common side effects of Paxlovid treatment tend to be mild and include diarrhea, muscle aches, high blood pressure, and an altered sense of taste, Roberts says. However, the medication isn’t recommended for people with severe liver or kidney disease. 

Paxlovid also interacts with various other medicines. “The list is longer than most, and I think possibly most concerningly…it interacts with some medications that are really critical for many diseases,” Roberts says. “A lot of these patients who are high-risk for COVID…are on medications that do need to be evaluated before administering this.”

Some of these drugs include medicines for heart arrhythmias, immunosuppressants for organ transplant recipients, and blood thinners, he says. 

“Both the drugs [in Paxlovid] affect enzymes in the liver that normally help clear other medications from a person’s body,” Abinash Virk, an infectious disease specialist at the Mayo Clinic, said in an email. “Levels of some [of] these other medications may be increased or decreased.”

The drugs, or compounds, that makeup Paxlovid are nirmatrelvir and ritonavir. During treatment, patients take nirmatrelvir and ritonavir tablets twice daily for five days. While monoclonal antibody treatments for COVID-19 target the ever-changing spike protein on the novel coronavirus’s surface, Paxlovid prevents the virus from making copies of itself. Nirmatrelvir blocks a kind of enzyme known as a protease that would normally snip strings of proteins the virus makes during replication into smaller, functional pieces. Ritonavir, which was originally developed as an HIV medication, prevents nirmatrelvir from being metabolized.

“That component can hang around the bloodstream longer and act on COVID longer at much higher concentrations and work to inhibit viral replication in a more efficacious way,” Roberts says.

But Roberts explains that the presence of ritonavir in particular, “causes many drug levels to fluctuate wildly.” Often, this means the concentrations of drugs such as blood thinners rise “quite substantially” because they can’t be broken down properly.  

[Related: The FDA is inching closer to a long-term COVID booster plan]

Paxlovid can make some drugs less effective and sometimes cause serious or even life-threatening reactions. “Before a patient takes Paxlovid, the patient, the pharmacist and the prescriber should review all of the patient’s medications to identify and avoid clinically significant drug interactions,” Virk said.

Some medications, such as the statins used to treat high cholesterol, can be stopped for a few days while the patient is taking Paxlovid, Roberts says. In other cases, the dosage can be adjusted. Paxlovid may affect how some birth control pills work, so people taking them should consider using a backup form of contraception while undergoing treatment. 

Unfortunately, some drugs cannot be safely discontinued while a person is on Paxlovid, including certain heart and anti-seizure medicines, Roberts says. 

There’s also a concern that in people with undiagnosed or uncontrolled HIV, the exposure to ritonavir could teach the virus to become resistant to HIV drugs that work similarly. In theory, this could mean these drugs won’t work as well if the person needs them in the future to treat their HIV. However, Roberts says, the Infectious Diseases Society of America considers this very unlikely since Paxlovid treatment is so brief. Additionally, Paxlovid can be given along with antiretroviral therapy to COVID-19 patients who have HIV. 

Pfizer told Popular Science in an email that it’s working to educate physicians, pharmacists, and other healthcare providers on how to manage potential drug interactions with Paxlovid. “We are also working with some of the largest telemedicine companies to ensure their [healthcare providers] are knowledgeable about PAXLOVID and ready to treat appropriate patients, and we are reaching out to pharmacy customers directly to help address questions,” the company said.

For those who cannot take Paxlovid, the antivirals remdesivir and Molnupiravir may be an option.

Paxlovid is still really effective

Roberts suspects that in time additional antiviral medications will become available that match Paxlovid’s advantages without interfering with so many other medications. Something similar happened with HIV treatments, Roberts notes, which initially contained ingredients that caused a lot of interactions with other drugs.  

“They came out with a new class of medications that do not require those [ingredients], and that drug-drug interaction concern is significantly lowered,” he says.

Although Paxlovid does have limitations, Roberts emphasizes that “It’s a really game-changing drug.”

Antibody treatments, which have fewer known adverse drug interactions, worked against previous versions of the virus, but were rendered ineffective against Omicron because the variant’s spike protein has so many mutations. Paxlovid, on the other hand, has held up well against Omicron in laboratory tests. It also has the added benefit of being taken as a pill, while other treatments, such as remdesivir, must be taken intravenously, explains Roberts. Merck’s antiviral Molnupiravir is also given orally, although it only reduced hospitalizations and deaths by 30 percent in clinical trials.

[Related: COVID antiviral pills work against Omicron—when people can get them]

Preliminary data also indicate that Paxlovid protects non-high-risk patients—clinical trial participants who were treated with medicine were 70 percent less likely to be hospitalized than COVID-19 patients who were given a placebo. 

“The next big frontier I think with Paxlovid is expanding its use to even low-risk people,” Roberts says. “As more data comes out and supply increases…anybody diagnosed with COVID might qualify for Paxlovid.”

Researchers are optimistic the drug will also be effective against future variants of SARS-CoV-2 as well as other coronaviruses, Roberts says.

Until then, he advises people to get tested as soon as possible if they develop COVID-19 symptoms, and inform their doctors if they test positive. Like Tamiflu, the earlier Paxlovid is given the better its chances of success. 

“I would advise patients if they do have COVID the first and foremost treatment to look at would be Paxlovid,” he says. “That would be my first choice for anybody in the outpatient setting testing positive who qualifies.”

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The record-breaking 2020 Atlantic hurricane season spawned 30 named storms, 11 of which struck the United States coastline. The combined effects of high winds, storm surge, and heavy rains caused more than $40 billion in estimated damage.

A new analysis focused on extreme rainfall suggests that climate change played a significant role in this destructive period. Scientists used computer simulations to compare the 2020 hurricane season under contemperatory and preindustrial climate conditions, and concluded that rising sea surface temperatures increased the peak three-hourly tropical storm rainfall rates by 10 percent.

“Climate change isn’t an end-of-the-century problem; it’s actually here,” says Kevin Reed, a climate scientist at the State University of New York at Stony Brook. “It’s changing our weather and therefore we must really think about how we [can] best adapt our coastlines and become more resilient to these types of events and how they’re changing.”

Reed and his collaborators reported the findings on April 12 in Nature Communications.

In recent years, scientists have explored how climate change has worsened individual storms such as Irma, Maria, and Harvey in 2017; Florence in 2018; and Dorian in 2019. This involves a technique known as hindcasting, in which researchers try to recreate past weather rather than predicting upcoming conditions. Otherwise, though, “It’s no different than the National Weather Service running a seven-day forecast so that you can know what weather might be like on Saturday,” Reed says. 

[Related: The future of hurricanes is full of floods—a lot of them]

His team investigated how climate change might have influenced the entire 2020 hurricane season in the North Atlantic basin. They used climate models to generate two sets of hindcasts that ran every three days from June 1 through November 30. One set was based on simulated 2020 conditions, while the other represented a world whose climate hadn’t been altered by human activities. 

The global average surface temperature increased due to greenhouse gas emissions by more than 1 degree Celsius (1.8 degrees Fahrenheit) from 1850 to 2020. As a result, the researchers estimated, sea surface temperatures in the North Atlantic were between 0.4 to 0.9 degrees Celsius (about 0.7 to 1.6 degrees Fahrenheit) warmer during the 2020 hurricane season than would be expected without human interference. And scientists know that warmer waters enable more powerful storms to form. 

Tropical storms can wreak havoc by unloading vast amounts of rain in torrential but short-lived downpours, as the remnants of Hurricane Ida did last year in the Northeast. In other cases, such as Hurricane Harvey, take days to disgorge their rains over an area. Reed and his colleagues examined rainfall hazards by calculating levels over three-hour and three-day periods. 

The team estimated that climate change boosted the most intense three-hourly rainfall rates and accumulated three-day rainfall amounts for tropical storms by, respectively, 10 percent and 5 percent during the 2020 season. When the researchers limited the analysis to storms that reached hurricane strength, they found that climate change increased extreme three-hourly and three-day rainfall by 11 percent and 8 percent, respectively. 

“That last part is a really important finding,” Reed says. “It shows that the climate change signal is larger in more intense storms.” These extreme storms have stronger winds that can transport more moisture from the sea surface towards the storm center, where the heaviest rainfall occurs, he says. 

[Related: As sea levels rise, where will all the people go?]

The new results are “very reasonable,” says Haiyan Jiang, an atmospheric scientist at Florida International University in Miami who wasn’t involved with the research.

“It’s in line with the previous findings that if we have a warming climate…it will drive the sea surface temperature higher, and if we have a high sea surface temperature then we’ll have more stronger storms and storms with heavier rainfall,” she says.

However, it will still be important to verify the estimates by consulting weather records from 2020, says Jiang, who has also analyzed satellite data to determine that global average rainfall from tropical cyclones has increased about 1.3 percent per year in recent decades. “The strong evidence is in the observations,” she says.

The researchers have previously compared hindcasts with observed rainfall levels for individual storms that made landfall, Reed says. “It’s a little harder to capture rainfall over the open ocean, which is in part what we’re including in this analysis,” he says. “But as new satellites and new observational data become available, we will continue to evaluate that.”

The team also plans to run similar analyses for the 2021 and upcoming 2022 hurricane seasons and to simulate hurricane seasons under possible future climate conditions.

“As we project into the future in which we’ll see more and more warming, we can anticipate that these percentages will get larger and larger,” Reed says.

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In late June of 2009, a weather pattern called a cut-off low brought three days of drenching rains to Austria, causing river flooding in the northern part of the country and landslides in the southeast. In one district adjoining the Austrian Alps, the downpours triggered more than 3,000 landslides that destroyed streets, houses, and agricultural lands and cost the state of Styria more than $14 million.

Disasters like this one may become even more damaging in the future due to climate change, a new analysis suggests. Scientists simulated how landslide risk in the Austrian Alps might change if a weather pattern similar to the 2009 event played out under several global warming scenarios. They calculated that the area struck by landslides could increase by up to 45 percent in the most dire situation. However, possible changes in soil moisture and planting climate-resilient forests across the region could combat these effects, the group reported on April 7 in the journal Communications Earth & Environment.

“There is a real risk that landslide hazard will increase in a warming climate in the [Alpines],” says Douglas Maraun, a climate scientist at the University of Graz in Austria and coauthor of the findings. “We investigated just one event, but you can take it in a way as representative for similar regions and similar events.”

George Hilley, a geologist at Stanford University who wasn’t involved with the research, describes the team’s approach as “quite clever.” 

“It was also very interesting to see the kind of differences in hazard levels that would be wrought by these types of [weather] events under…the different scenarios that they explored,” he says. “In some of them the hazard level goes up with warming, and in some cases it actually goes down because of the complex interplay between the soil moisture and the rainfall intensities that would be expected in the future.”

Landslides can have many causes, including earthquakes, volcanic eruptions, human activities, and waterlogged soil. “When the soil is very wet it gets heavy, and then it starts sliding down if the soil is not really held together by, for example, tree roots,” Maraun says. The ensuing landslide may rush down a slope within a matter of seconds or creep a few inches per day, he says. Climate change is expected to make landslides more likely due to wildfires that burn up vegetation and destabilize the soil, erosion related to sea level rise, and more extreme rains. 

In the Austrian Alps, Maraun says, rain is the main culprit behind landslides. Heavy snowfall during the winter of 2009 may have dampened the soil in the Feldbach district and primed the region for more severe landslides when the June storms arrived.

[Related: Climate action is a ‘now or never’ situation, IPCC warns]

Maruan and his collaborators used computer models to simulate a weather pattern similar to the 2009 event under contemporary and possible future climate conditions. These included a worst-case scenario with 4 degrees Celsius (7.2 degrees Fahrenheit) global warming, a business-as-usual scenario with 3 degrees Celsius (5.4 degrees Fahrenheit) warming, and a more optimistic scenario in which warming is limited to 0.5 degrees Celsius (0.9 degrees Fahrenheit).

The 2009 landslides occurred in a region of the Alpine forelands—the land along the edge of a mountain range where sediments are deposited—that was roughly 30 by 20 kilometers (18.6 by 12.4 miles) in size. For the analysis, Maraun’s team included a plot of 200 by 200 kilometers, or 124.3 by 124.3 miles—which is twice as large as Lake Ontario.  

Within the scenarios, the researchers examined how varying changes in summertime rainfall and in soil moisture prior to the event may interact to alter landslide risk. As temperatures rise the soil may become drier because warmer air can hold more water, Maraun says, causing evaporation to increase. 

In a worst-case climate scenario with much heavier rainfall, landslides could pummel an area 45 percent larger than was affected by the 2009 event. However, drier soil could counteract this change and even decrease the size of the affected area. Similarly, in a business-as-usual world where the Alps experience heavier rainfall but have much drier soil, the affected area would decrease by 37 percent. And in the most optimistic climate scenario, the changes in rainfall and soil moisture would likely be minimal enough that the affected area would increase by less than 10 percent. 

The researchers also found that changes in vegetation cover could limit landslide risk during a 2009-type event. Spruce trees have been planted throughout the Alpine forelands because they offer a fast-growing source of wood, but they’re vulnerable to the hot, dry conditions that climate change will bring. It’s likely that forest managers will replace these evergreens with hardier trees that happen to have deeper root systems, Maraun says. 

[Related: Artificial snow might save a glacier in the Swiss Alps]

If so, he and his colleagues estimated, the area affected by landslides under the most extreme warming and rainfall possibilities would grow by only 37 percent rather than 45 percent. In the most optimistic climate scenario, the forests would actually offset the increase in landslide hazards.

“When you’ve got areas that have a very high risk of landslides…you could grow forests to secure the land and then you could compensate for the increasing risk [caused] by climate change,” Maraun says. However, the district is also an agricultural hub and land is needed for farms. Additionally, the region’s highest biodiversity is found in habitats that blend forest and meadows, so balancing land management with conservation will be crucial. 

“The answer here can’t be that we just try to reduce the risk to zero by growing trees everywhere,” Maraun says. 

Much uncertainty remains about how climate change will alter rainfall and soil moisture in the Alpine forelands and beyond. Still, applying the techniques used in the new report to other places could help managers make decisions about how best to prepare for landslides, Hilley says.

“These types of scientific studies have important applications for how we’re going to be able to cope with the changes in these hazard levels in the future and the strategies that we can use to adapt to them,” he says.

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While writing of their 19th-century voyages to document the world’s biodiversity, European naturalists like Charles Darwin and Alfred Russel Wallace were struck by the appearance of the plants and animals they encountered in the tropics.

“The new organisms that they were observing were, to their eyes at least, incredibly rich and varied in color,” says Christopher Cooney, an evolutionary biologist at the University of Sheffield in England.

Their remarks sparked the controversial notion among scientists that animals and plants living near the equator are more colorful than those found at higher latitudes. But a new report by Cooney and his colleagues demonstrates that, for songbirds at least, this pattern holds true. 

[Related: Hummingbirds can see colors we can’t even imagine]

The researchers scrutinized 4,500-plus species from around the world and found that adult birds that bred in the area between the Tropic of Cancer and the Tropic of Capricorn boasted a more impressive diversity of colors than those native to other regions. The findings hint at several climactic and social pressures that might underlie the trend, the team reported on April 4 in the journal Nature Ecology & Evolution. 

“They did a great job of really capturing the breadth of what’s going on across the globe … and showing convincingly that this age-old idea is well-supported,” says Eliot Miller, an ornithologist at Cornell University who wasn’t involved in the research.

The color gradient that Darwin and his peers proposed has remained “shrouded in uncertainty,” Cooney says, for several reasons. Most prior studies have focused on limited geographic regions and used subjective measures of colorfulness, he and his collaborators wrote in the new paper. 

To address the question of how coloration changes with latitude, the team analyzed 4,527 species of passerines—which make up about 60 percent of known avian species and are often referred to as songbirds or perching birds—found in every habitat from the poles to the tropics. The researchers photographed the plumage of male and female specimens from the Natural History Museum at Tring at three different angles in visible light and in ultraviolet light that’s visible to birds. They then used computer algorithms to identify the pigments captured at 1,500 points on each body. “We wanted to generate estimates of colorfulness that are meaningful to the birds themselves,” Cooney says. 

Miller points out that the inclusion of UV makes the analysis more complete. “They can do a better job of describing what birds can see in that way rather than just what we see,” he says.

From there, Cooney and his team measured the number of distinct hues in each individual’s feathers, and concluded that male and female birds near the equator were indeed on average more colorful than their temperate cousins. They estimated that colorfulness increased by roughly 20 to 30 percent from the polar regions towards the tropics.

The most colorful species the researchers examined was the paradise tanager, a small Amazonian songbird whose plumage is a riot of intense blues, greens, reds, and black. Next to the tanager, many high-latitude birds were “uniformly drab,” Cooney says. 

“There are exceptions to the general trend,” he adds. “It isn’t a hard-and-fast rule that there aren’t colorful birds outside the tropics.” The US has a number of colorful birds, including the painted bunting and American redstart.

The kinds of habitats where these colorful birds dwell might shed light on why they developed their vivid displays. Cooney and his colleagues observed that specimens tended to be more colorful in warm, wet environments and dark, enclosed forests. “Those conditions do occur outside of tropical regions and potentially explain why places like the Eastern US … do have very colorful species as well,” Cooney says.

Birds in heavily forested areas might require bright, flashy plumage to catch the attention of other members of their species in the dimly lit understory. What’s more, food is typically more abundant in moist, lush places like tropical rainforests than it is in the tundra and other harsh landscapes. “There’s just more energy available in those environments that organisms can potentially invest in traits that are showy,” Cooney says. It’s also possible that some species acquire the eye-popping pigments in their feathers from fruits and nectars that are more readily available in the tropics than at higher latitudes.

[Related: Can birds smell? This ornithologist is debunking a long-standing myth.]

The researchers further noticed that colorfulness seemed to correlate with the songbird diversity in a habitat. Species in more crowded patches might have evolved to be brighter so potential mates and rivals could differentiate them from their neighbors, Cooney says. 

Still, he emphasizes, additional studies are needed to explore the patterns he and his team documented. “There’s a huge amount more to be learned about the precise ecological and evolutionary forces that promote colorfulness,” Cooney says.

Another open question is whether songbirds are just one example of how life is more colorful in the tropics. “[Early naturalists] were talking about not just birds but other things like plants and insects and fish,” Cooney says. “It remains to be seen whether this is a general phenomenon that applies to all types of organisms, but I would suspect that it does.”

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This week the U.S. Food and Drug Administration authorized a second booster dose of COVID-19 vaccines for older people and some immunocompromised people who received their first booster at least four months ago. 

Under the new guidance, the agency said, all adults 50 and older and individuals 12 and older who have received an organ transplant or have an equivalent level of immunocompromise may receive the additional booster of an mRNA vaccine.

“Current evidence suggests some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, noted in the announcement. “Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals.”

For now, studies indicate that a single booster dose provides strong protection against severe COVID-19 in most people. But a second booster may have advantages for those who are most vulnerable to COVID-19, experts say.

“These data are still relatively early,” says Jonathan Li, an associate professor of medicine at Brigham and Women’s Hospital and Harvard Medical School. “But on the other hand, it’s clear to me that your antibody responses do wane over time and to get the optimal benefit I think that having a second booster makes a lot of sense right now.”

The move comes as an extremely contagious Omicron subvariant sweeps the country. 

“I would say people don’t need to rush out and get the booster, but for those who are older, who have more medical conditions, this is something to seek out,” says Preeti Malani, the chief health officer and an infectious diseases professor at the University of Michigan. “I don’t see a lot of downside to this other than the inconvenience of getting another booster.”

Is protection from boosters waning?

The Centers for Disease Control and Prevention recently analyzed how effective the vaccines were in preventing emergency room and urgent care visits as well as hospitalizations in 10 states during the Omicron wave. The researchers observed that protection did decline somewhat around two to four months after participants received their second or third dose of an mRNA vaccine. 

It’s unclear how generalizable these data are. The report didn’t account for mild COVID-19 infections that did not require medical attention. It only included a small number of participants who’d gotten boosted at least four months prior to data collection. Because people in high-risk groups in the US had access to a third dose earlier than the general public, they might have made up a disproportionate share of the participants. The study authors note that this may have caused the third dose to seem less effective since immunocompromised people may not mount as strong of a response as those who do not have preexisting conditions.

[Related: A deep dive on the evolution of COVID and its variants]

However, the finding “reinforces the importance of further consideration of additional doses” to bolster protection against COVID-19, the team concluded on February 11. The researchers also noted that the vaccines remained more effective in people who’d had a third shot than those who only received two. 

“The third dose is really important, especially when it comes to Omicron,” Li says. “You really get full protection from severe disease against Omicron with the third dose.”

Even so, the majority of COVID-19 hospitalizations are still occurring in people who haven’t been vaccinated, Malani says. A study released on March 18 by the CDC found that when Omicron was peaking in January, hospitalization rates among unvaccinated adults were four and 12 times higher, respectively, than in adults who received their primary vaccine series and adults who received a booster. 

What’s the data say about second boosters?

Knowledge about how much protection a second COVID-19 booster provides is still preliminary, Li says.

Some data has begun to emerge from Israel, which has been offering a fourth shot to adults 60 and over, healthcare workers, and immunocompromised people since January. One recent study, which was posted on March 24 to the preprint site Research Square and is currently undergoing peer-review, found that older adults who received a fourth dose of an mRNA vaccine were 78 percent less likely to die of COVID-19 than those who’d only had three shots. 

“Our study results may provide primary evidence regarding the life-saving potential of an additional booster dose,” the researchers wrote. However, they added, it’s still critical to reach those who haven’t received any COVID-19 vaccines, and follow-up studies are needed to determine how durable the effectiveness of the second booster will be. 

[Related: Just had COVID? Here’s when you should get a booster.]

In a March 16 letter to the New England Journal of Medicine, another team reported that a fourth mRNA vaccine dose restored antibody levels in healthcare workers to similar levels seen after the third shot. However, the fourth dose didn’t add much additional protection against infection, suggesting that young, healthy people may only receive “marginal benefits” from the extra shot.

“What data we have suggests that the more comorbidities that you have—the higher the risk that you are of having severe disease—the more benefit you will have from a second booster,” Li says. “I would urge people who are eligible–those who are older, those who are immunosuppressed—really to take advantage of this and to get the second booster when you can.”

Malani, who is 52, says that she plans to get a second COVID-19 booster now that she is eligible. “It’s more about disruption, for myself personally, than worrying about severe illness,” she says. “For my parents and in-laws, this is a recommendation that I feel good about because I know that they have travel plans and grandchildren graduating, and I want them to be able to enjoy all those moments and at least mitigate that risk.”

Some people with weakened immune systems may still not mount a robust response even after a second booster, Li adds, but for this group long-acting monoclonal antibodies, lab-made proteins intended to prevent COVID-19, can provide additional protection. 

How long will the second booster last?

That remains to be seen.

“We are still in some uncharted waters here in terms of how long will a second booster last for,” Li says. So far, most research has focused on how boosters affect antibody levels. But scientists must also investigate how well the T-cell response—another arm of the immune system that helps stave off severe disease—endures after vaccination. For now, the FDA’s guidance offers a good rule of thumb for when you should receive the shot, he says.

It’s possible that people who get their second booster now may wind up getting another booster at some point, Malani acknowledges. “I don’t think there is a perfect way to time this,” she says. But “for those individuals who are older, there’s really not a reason to wait.”

After a booster shot, she says, it’s a good idea to continue taking other preventative measures such as wearing masks while in crowded indoor spaces.

“We’re in such a different place than we were two years ago,” Malani says. “Even though vaccines haven’t proven to be the end of the pandemic, they’re the most important way that we can manage the pandemic and boosting is part of that strategy.”

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A mysterious, knobbly region on Pluto’s surface was once the site of volcanic eruptions that oozed forth massive amounts of ice. Stunning images captured by NASA’s New Horizons spacecraft have revealed this chilly volcanic activity.

Scientists analyzed the topography and chemical composition of the rugged landscape, which includes domes almost the height of Mount Everest. They determined that the area experienced multiple periods of ice volcanic activity that occurred fairly recently. The findings indicate that Pluto’s interior might be warmer, or better at retaining heat, than previously assumed, the researchers reported on March 29 in Nature Communications.

“One big takeaway is that Pluto and [its moon] Charon and all these bodies in the outer solar system are not these cold, dead things,” says Steven Desch, a planetary scientist and astrophysicist at Arizona State University in Tempe who wasn’t involved with the new research. “They are active geologically, and they do a lot of interesting things.”

The volcanoes we’re familiar with on Earth spew molten rock. On distant frigid worlds, a similar phenomenon occurs when ice is heated within the crust and thaws enough to flow up through cracks in the surface, Desch says.

Ice volcanism (also known as cryovolcanism) is thought to occur on bodies such as Charon, Jupiter’s moon Europa, Neptune’s moon Triton, and the dwarf planet Ceres. As the slush erupts onto the chilly surface and hardens, it can accumulate in mounds or flood over the ground to form plains, says Kelsi Singer, a planetary scientist at the Southwest Research Institute in Boulder, Colorado and coauthor of the new report.

[Related: Frigid Pluto may have had a toasty start]

She and her collaborators suspected that a region to the southwest of Pluto’s Sputnik Planitia ice sheet may once have been a hotbed (or coldbed) of cryovolcanic activity. Today, it’s covered in enormous domes that are carpeted with smaller bumps and form a rough, “undulating” terrain, Singer says. 

“There’s lumps on top of lumps, and then there’s even smaller texture on top of that,” she says. “It’s not smooth at any scale that we can see.”

The lumpy features visible in the pictures snapped by New Horizons as it zipped past Pluto in 2015 cover an area of about 300 by 600 kilometers, or 186.4 by 372.8 miles. However, there may be even more signs of volcanic activity shrouded in darkness, Singer says.

To investigate whether the odd mounds were evidence of cryovolcanism, the researchers built a topographical map of the area using images captured from many different angles. This allowed them to make detailed estimates of the shapes and sizes of the domes, the largest of which reached roughly 7 kilometers (4.3 miles) in height and had a volume similar to Hawaii’s Mauna Loa. 

The team realized that the region was dotted with mounds from many different vent sites, some of which had merged together over time. Additionally, the researchers identified bumps that appear to be “overprinted” on older features, indicating that multiple volcanic episodes had occurred. Based on the lack of impact craters left on the surface, Singer and her colleagues concluded that much of the cryovolcanic activity happened—geologically speaking—pretty recently, perhaps within the last 100 million to 200 million years. 

“We can’t rule out that it’s ongoing,” she says, noting that volcanoes on Earth can go dormant for many years between outbursts. “There could be more episodes to come.” 

During its flyby, New Horizons also collected data on the terrain’s chemical composition. The researchers determined that the cryovolcanic mounds were primarily water ice with smaller amounts of frozen nitrogen and other compounds mixed in. Different types of ice have their own melting points and other properties, Singer says, which would have influenced how the structures formed.

She and her collaborators used computer models to simulate how cryovolcanism could have created the domes. The process probably wasn’t explosive like many Earthly eruptions. Rather, it might have resembled the slow percolating formation of bulbous structures called pillow lavas “but on a giant scale,” Singer says.  

[Related: How Pluto keeps its secret ocean warm]

Pluto lies far from the sun’s warmth, in the ring of icy objects beyond Neptune’s orbit known as the Kuiper Belt, and has an average surface temperature of -387 degrees Fahrenheit. To keep moving in these bitterly cold temperatures, the “lava” that emerged from Pluto’s cryovolcanoes likely contained salts that acted like antifreeze. Even so, the material was probably a smoothie texture or nearly solid ice that flowed similarly to a glacier. “We imagine it more as a toothpaste-like or silly putty-like kind of flow, where it’s not completely fluid,” Singer says.

The new paper makes “a pretty strong case” for cryovolcanism on Pluto, Desch says. The findings also add weight to the possibility that Pluto’s interior is warm enough to host liquid water. Scientists have speculated that an ocean may be located more than 60 miles beneath the surface, where the icy shell meets the rocky core. To feed the cryovolcanic activity Singer and her team observed, however, Pluto may also have “little pockets of warmer areas” of water or partially melted slush at shallower depths, she says.

“If this is corroborated as cryovolcanism, it basically clinches the case for subsurface liquid, which the models have been leaning towards in the last decade or two,” Desch says. “And if Pluto has subsurface liquid, it’s likely a lot of the Kuiper Belt objects do, so it has a lot of far-reaching implications.”

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Vampire bats are pretty unusual creatures, even by bat standards. 

They’re the only mammals to dine exclusively on blood, which means their bodies have needed to adapt in many ways to this challenging diet. Vampire bats also boast very advanced social skills, says Michael Hiller, a professor of comparative genomics at the LOEWE Centre for Translational Biodiversity Genomics in Frankfurt, Germany. 

Hiller and his collaborators are investigating the genetic changes that have enabled vampire bats to thrive. They analyzed the genomes of common vampire bats and more than two dozen other bats, and have identified 10 genes that are no longer functional in the vampires. Several of these alterations may help the bats cope with the high iron levels in blood and contribute to their impressive cognitive abilities, the team reported on March 25 in Science Advances.

“These gene losses tell us a lot about past natural selection in the vampire bat lineage,” Gerald Carter, a behavioral ecologist at Ohio State University who wasn’t involved in the new research, said in an email. “These traits are not just about how they digest blood. It extends out to how they behave and even how they think.”

Blood is a “suboptimal” food source because it’s nearly 80 percent fluid, while the rest is largely made of protein, with very few fats and sugars, Hiller says. Since blood is so low in calories, vampire bats must slurp down as much as 1.4 times their body weight in a single meal.

Among their other specializations, vampire bats have infrared sensors around their noses, razor-sharp and enamel-less incisors to slice through their unsuspecting dinner’s skin, and anticoagulants in their saliva to keep the blood flowing while they feast. They’re also adept at sneaking up on prey by hopping along on their elbows and can even run and jump. “They have pretty exceptional terrestrial locomotion skills, while in other bats it’s much more limited,” Hiller says. 

[Related: Female vampire bats regurgitate bloody dinners for their starving girlfriends]

Because of their low-nutrient diet, vampire bats are very vulnerable to starvation. Sated bats regularly share regurgitated blood with neighbors who failed to obtain their nightly meal. “The decision with whom to share blood is primarily driven by who was helping you out in the past,” Hiller says. This means that vampire bats can recognize their roost mates and remember their past actions. They also form lasting social bonds; Carter and his colleagues have observed that captive bats will stick together even after they’ve been released.

In order to support their sanguivorous lifestyle, Hiller says, vampire bats have likely tweaked their genetic instructions in various ways. His team focused on genes with mutations that destroy their ability to encode working proteins. Often, such genes are inactivated because they’re no longer useful for the animal, while in other cases losing a gene can actually provide a survival advantage. 

To understand how these processes might have played out in vampire bats, the researchers sequenced the genome of one of the three known species. They then compared it to published genomes of 26 other bats, searching for genes that were missing in the blood-suckers but present in their closest and more distant relatives. 

“We were asking, using this new genome, which genes were specifically inactivated along that branch leading to the common vampire bat,” Hiller says. He and his colleagues pinpointed 13 gene losses in vampire bats that seem to be related to their distinctive traits. 

Three had been reported previously and were linked to sweet and bitter taste perception, indicating that vampires have a poor sense of taste. “If you only feed on blood from a live animal, you don’t have to worry about the meaning of new flavors or your food being spoiled,” Carter noted.

Similarly, among the 10 newly-discovered gene losses, Hiller says, “We think the simplest explanation for many of them is likely what people describe as ‘use it or lose it.’” 

Vampire bats get barely any sugars and fats from their meals, so several genes involved in processing these nutrients were perhaps no longer needed. Nor was a gene related to stomach acid secretion. “Their stomach has been converted from a digestive organ that secretes acid, like us and other bats, to a distensible storage organ,” Hiller says. Vampires prefer to hunt in the darkest hours of night—they even avoid moonlight—so genes necessary for color vision were probably also rendered obsolete. 

[Related: Vampire bats socially distance when they feel sick]

Other genes played roles in digesting proteins and combating potentially dangerous microbes, but it’s unclear why they were inactivated. One possibility is that the immune-related gene lost its importance because the pathogens present in blood are so different from those in other tissues of the prey animals’ other tissues, Hiller says.

Most exciting, he says, were two cases where ditching a particular gene seems to have directly helped vampire bats adapt to their “very specific” lifestyle. 

Vampire bats consume up to 800 times the amount of iron that humans do, which can have dangerous consequences. However, the researchers identified a gene loss that allows the short-lived intestinal cells to soak up more of the mineral before they’re shed into the gut and pooped out. This could keep the bats’ iron levels in check.

The other inactivated gene codes for an enzyme that normally breaks down a molecule produced from cholesterol. That molecule stimulates parts of the brain involved in learning, memory, and social behavior. In the future, the researchers plan to measure whether losing the enzyme has given common vampire bats elevated levels of the cholesterol-based molecule, which might underlie some of their social habits. 

The team has also recently sequenced the genomes of the two remaining vampire bat species and will compare all three sets of genetic instructions in detail. And, while the new findings highlight how gene loss can be an important evolutionary mechanism, Hiller says, it’s not the whole story. 

“Gene loss is only one kind of genomic change,” he says. “With the new genomes we have, we would now like to run more comprehensive screens to better understand the underpinnings to these adaptations.”

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More than 90 million years ago, a dinosaur similar in size to T. rex cruised through shallow waters in search of prey, scientists reported today in the journal Nature. 

A number of ancient reptiles such as plesiosaurs and ichthyosaurs are known to have had marine lifestyles, but dinosaurs have generally been considered landlubbers. However, an analysis of the density of 380 bones belonging to a variety of dinosaurs, other extinct creatures, and present-day animals suggests that the iconic Cretaceous dinosaur Spinosaurus and one of its close relatives were capable swimmers. 

Based on the new findings and other reports, it’s “strongly plausible” that Spinosaurus was an aquatic dinosaur, says Alexandra Houssaye, a paleontologist at the French National Natural History Museum in Paris who wasn’t involved in the research.

While Spinosaurus probably didn’t have the agility or diving abilities seen in today’s seals or dolphins, its bones suggest the enormous predator was more comfortable in water than on land and may have swam along the riverbed like a misshapen hippopotamus or crocodile, Houssaye says.

[Related: Most dinosaurs didn’t swim—but this ‘dino equivalent of Jaws’ sure did]

Spinosaurus belongs to a family of meat-eating dinosaurs known as spinosaurids that emerged during the Jurassic Period. They had narrow, crocodile-like faces and long spines along their backs that could grow to around 6 feet tall, says Matteo Fabbri, a paleontologist at the Field Museum of Natural History in Chicago and coauthor of the study. Although Spinosaurus wasn’t quite as heavy as T. rex, it was longer, with some specimens reaching an estimated 50 feet. 

The first Spinosaurus fossil was discovered in Egypt in the early 20th Century but was destroyed during World War II. During the 1980s and 1990s, researchers began to find fragmented fossils from Spinosaurus and its family members around the globe and surmised that spinosaurids were mostly land dwellers that sometimes waded through the water in search of fish, similar to present-day herons. 

Then in 2014, a Spinosaurus skeleton in unusually good condition was identified in Morocco. “It’s created a huge debate in the field of paleontology,” Fabbri says. He and his collaborators noted a number of traits, including stubby hindlimbs and paddle-like feet, that hinted that the dinosaur was at least partly aquatic. In 2020, the team reported that Spinosaurus’s tail had an unusual fin-like shape that could have propelled it through the water similarly to the tails of modern crocodiles. 

Still, Fabbri says, it can be difficult to judge how much time an animal spent underwater by the shape of its bones. Today’s whales and seals have plenty of skeletal characteristics that reveal their aquatic tendencies. But in other water-loving species, such as hippos and tapirs, these features aren’t as obvious. 

Even though they have a well-documented aquatic lifestyle, “if you look at skeletons of hippos they look much more like terrestrial animals than anything else,” Fabbri says. “So is it possible that maybe we’re underestimating the ecological diversity of the fossil record because we are only focusing on anatomy?”

To address this question, he and his colleagues measured the bone density of Spinosaurus and two other spinosaurids, Baryonyx and Suchomimus, and compared them to other dinosaurs and extinct reptiles, Cretaceous birds, as well as a wide array of modern birds, mammals, and reptiles. The researchers examined the thighbones and ribs of their specimens using CT scanning and by examining thin slices of bone under the microscope.

“Higher density means there’s more tissue per single volumetric unit,” Fabbri says. “If you are an aquatic animal…if you are denser you can sink easily, and therefore you have more buoyancy control.”

Animals that submerge themselves underwater, such as hippos, manatees, crocodilians, and penguins, have denser bones than terrestrial animals and aquatic animals that dive deeply to search for food, including ichthyosaurs and modern whales and seals. These more active swimmers rely on their own movements, rather than bulky bones, to control their buoyancy, Houssaye says. When land-dwelling animals such as the ancestors of today’s whales take to the water, dense bones evolve early in the transition. “​​The inner structure changes more quickly than the shape of the bones,” she says.

Fabbri and his team observed that generally an animal’s bone density was mostly unrelated to its body size. They also noted that flying animals were somewhat more likely to have lightweight bones, and the densest bones were found among aquatic animals. In shallow-water specialists, he says, “You don’t have this donut-shaped cross section where you have bone outside and emptiness in the middle; you simply have a lot of bone that reaches to the center.”

The researchers found that both Spinosaurus and Baryonyx had extremely dense bones, similar to penguins, cormorants, and plesiosaurs. They may have returned to land to lay their eggs, Fabbri says, but probably spent most of their time in the water. 

[Related: These ancient, swimming reptiles may have been the biggest animals of all time]

On the other hand, Suchomimus had bones more similar to the other dinosaurs included in the analysis, suggesting it didn’t hunt underwater like its cousins. However, Suchomimus’s elongated snout and cone-shaped teeth suggest that it did feed on fish, and may have waded along riverbanks. 

Most dinosaurs probably weren’t built for living in the water, Fabbri says. Nonetheless, there may be other extinct animals who were better suited for swimming than scientists have previously assumed based on the shape of their bones. The next step, he says, is to measure the bone density of a broader array of dinosaur fossils.

“The fossil record is pretty patchy, meaning that a majority of skeletons are very fragmentary,” Fabbri says. “So this was very exciting because it was a way to say, okay not only can we understand the ecological adaptations in the fossil record, but you don’t need a full skeleton to understand it.”

One limitation of the analysis is that very compact ribs are sometimes seen in land animals, Houssaye notes, so these bones aren’t necessarily indicative of an aquatic lifestyle. Still, the densely-packed thighbones Fabbri and his colleagues observed in Spinosaurus do suggest that these dinosaurs were water dwellers. In the future, she says, researchers may find more evidence for Spinosaurus’s aquatic nature by examining the density of additional bones such as the forelimbs and investigating whether density is consistent throughout the length of the bones.  

“Because there are not many bones, we need to exploit them as much as possible,” she says.

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An Italian study of high-risk volunteers found that vaccine side effects were similar to those seen in the general population

Moderna and Pzifer’s mRNA-based COVID-19 vaccines are safe for immunocompromised people with a wide range of illnesses, a new analysis shows.

Researchers in Italy tracked more than 550 people in fragile health who received two doses of an mRNA vaccine, and found that the side effects were in line with those experienced by the general population.The individuals who participated have immune systems that have been weakened by illness or treatments such as chemotherapy. “Our patients did not show a higher incidence of severe adverse events and we did not see an increased risk of discontinuation of treatment programs due to vaccination,” Nicola Silvestris, a professor of medical oncology at the University of Messina in Italy, said in a statement. “Therefore, vaccination for COVID-19 is confirmed as safe, even in this group of high-risk patients.”

Silvestris and his collaborators reported the findings on March 17 in the journal Frontiers in Oncology.

“This is reassuring data,” says Erin Longbrake, an assistant professor of neurology at the Yale School of Medicine who wasn’t involved in the research. “We want to give these vulnerable patients every layer of protection that we can, and they can be more confident in taking that vaccine, in taking that protection against COVID infections.”

[Related: If you’re unsure about getting the COVID-19 vaccine, read this]

The clinical trials that originally assessed the safety and efficacy of the mRNA vaccines for COVID-19 focused on healthy volunteers. People whose health was frail due to cancer or other serious illnesses face a heightened risk of complications from COVID-19 but weren’t included in these studies. This led some to hesitate about getting vaccinated once the shots were authorized due to concerns about side effects or fears that the immune response prompted by the vaccine would worsen their disease. 

“We need more data to understand what types of reactions these patients will have,” says Karen Reckamp, the director of the division of medical oncology at Cedars-Sinai Medical Center in Los Angeles and who was not involved in the research. “So the data we get outside the randomized trials can be very helpful [as] patients and physicians make decisions.”

Silvestris and his team recruited 566 adults from across Italy who were being treated for blood cancers, solid tumors, and neurological or autoimmune diseases from March to early September of 2021. Twenty-eight percent of the participants were young adults, almost 53 percent fell between the ages of 51 to 70 years, and nearly 19 percent were older than 70. The research group evaluated their responses to the Moderna or Pfizer vaccines via questionnaire; all but 10 received both doses. 

About 77 percent of the participants reported experiencing side effects after the first dose, including 11 percent who described their symptoms as severe. After the second dose about 66 percent of participants reported side effects, and about 15 percent said their symptoms were severe. The most frequent side effects were pain at the injection site, fatigue, bone pain, headaches, and fever. Other symptoms included nausea, diarrhea, insomnia, skin rashes, or enlarged lymph nodes.

Additionally, younger people were more likely to experience severe fever than older ones, and women had an increased likelihood of severe symptoms. People who received the Moderna vaccine were more likely to report severe fever and pain at the injection site than those who were given Pfizer’s shot. The only severe symptom that varied by disease was injection site pain, which was more common in people with neurological or autoimmune diseases than in people with cancer.

Two participants died during the course of the study, but their deaths were caused by their underlying illnesses and not related to vaccination, the study authors report. None of the participants were hospitalized due to side effects from the vaccine, and less than 2 percent of the participants had to delay treatment for their illness while they coped with side effects.

“Whatever the underlying disease…the mRNA-COVID-19 vaccine should be considered a crucial step to allow a safe program of treatment more than a possible obstacle or danger to pursue the control of the disease,” Silvestris and his team concluded in the study. 

The findings are consistent with a number of other reports that have concentrated on people with cancer, multiple sclerosis, and other medical conditions that put them at high risk of becoming seriously ill from COVID-19 and found vaccination to be safe, the authors added.

[Related: Long COVID can manifest in dozens of ways. Here’s what we know so far.]

However, Longbrake and Reckamp note, immunocompromised people may mount a less robust immune response after vaccination than their peers, particularly if their treatments have depleted their antibody-making white blood cells. 

“We’ve established that [the vaccines] are safe,” Longbrake says. “Now we have to determine how effective they are relative to non-immunosuppressed individuals and whether or not there’s things that we can do to more effectively vaccinate this vulnerable population.”

This is also one more reason why it’s important for people who aren’t immunocompromised to still get immunized against COVID-19, she adds.

“Them getting vaccinated stands to protect this frail population in a large way as well,” Longbrake says. “It’s not just about them getting vaccinated, but it’s about everybody around them getting vaccinated too.”

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The spring allergy season may kick off earlier and last several weeks longer by the end of the century thanks to climate change, a new analysis suggests.

Scientists at the University of Michigan used computer models to simulate how changing weather conditions and carbon dioxide levels will affect pollen emissions for common trees, weeds, and grasses across the United States. They found that the timing and duration of the spring and fall pollen seasons will shift by the end of the century, leading to substantial increases in the amount of pollen unleashed annually.

The findings suggest that longer and more prolific pollen seasons in the country will aggravate asthma and hay fever, which currently plagues an estimated 10 to 30 percent of the world’s population, the team reported on March 15 in Nature Communications.

“This study can be a starting point for future investigations into the consequences of climate change on pollen emissions and also the subsequent health impacts,” says Yingxiao Zhang, an atmospheric scientist who coauthored the paper.

Previous studies have indicated that pollen seasons are sensitive to climate change. However, these observations tend to be limited to small areas, span short periods of time, or include only a few plant species. “We don’t have a ton of pollen data within the United States,” says Allison Steiner, the paper’s other coauthor. 

[Related: How to take seasonal allergy medications the right way]

To shed more light on what we can expect from future allergy seasons, she and Zhang investigated when, where, and how much pollen will be released over the continental United States. “This kind of information could potentially inform allergy sufferers in doing health and medication planning,” Steiner says.

The researchers used a computer model developed by the American Academy of Allergy, Asthma and Immunology to simulate emissions from 13 of the most common groups of pollen-producing plants in the US under two greenhouse gas emissions scenarios. The team compared their projections for the period from 2081 to 2100 with historical observations from 1995 to 2014.  

Zhang and Steiner explored how temperature, precipitation, and carbon dioxide concentration could shape future pollen seasons. Warmer conditions and elevated carbon dioxide levels can encourage plants to grow and produce more pollen, while rainfall can sometimes wash pollen away.

The team found that warmer temperatures could shift the start of spring pollen season between 10 to 40 days earlier and the summer-to-fall pollen season for weeds and grasses five to 15 days later. Under a scenario in which greenhouse gas emissions continue unabated, pollen seasons will last up to 19 days longer, while a more moderate emissions scenario would lengthen the season by up to 10 days. 

Rising temperatures could also lead to 16 to 40 percent more pollen released annually. When the researchers included the potential effects of carbon dioxide, which may increase dramatically later this century, annual pollen emissions more than doubled. However, information about how this gas influences pollen production is relatively sparse and mainly comes from laboratory experiments on small numbers of plants. 

“Temperature plays a main role for the pollen season change; it kind of extends the flowering season,” Zhang says. And more blooming means more pollen. “Currently we are thinking that carbon dioxide might become very important in the future, but it’s very uncertain.”

[Related: North Carolina’s ‘Pollenpocalypse’ is nothing to sneeze at—but you will anyway]

She and Steiner also examined how botanical communities might change as global warming renders different areas more or less hospitable to plants such as ragweed and oak. They concluded that these shifts in vegetation cover may worsen pollen seasons in some areas but they will probably have a smaller impact than temperature or carbon dioxide.

“In general the northern latitudes tend to see more warming, and so we see the bigger [pollen season] advances in those latitudes,” Steiner says.

In the future, the estimates she and Zhang developed could be improved by gathering more information about how climatic variables such as carbon dioxide and droughts impact pollen-producing plants, she says. 

Another key question is how carbon dioxide and temperature could cause flowers to produce pollen that humans are more sensitive to, says Lewis Ziska, an associate professor of environmental health sciences at the Columbia University Irving Medical Center who wasn’t involved with the research. There’s some evidence that increasing carbon dioxide levels can alter the proteins on the surface of pollen grains in ways that make them more potent allergens. 

Still, the new findings are “very consistent” with what Ziska and his colleagues have observed with atmospheric conditions and pollen production.

“They’re an important confirmation, particularly in the context of future climate,” he says. “They provide a very granular assessment of the scope of the change with respect to plant-based allergies.” 

Although many uncertainties remain about how future allergy seasons will play out under climate change, Steiner says, all the evidence indicates that we can expect significant changes in the timing and intensity of pollen production.

“We do still have control over the trajectory of what happens by 2100, and cutting emissions is going to be a key factor in reducing carbon dioxide concentrations and potentially mitigating some of this influence on pollen,” she says.

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As the Omicron-fueled wave in COVID-19 cases ebbs and vaccination rates increase, the country is beginning to shift gears in how COVID-19 is measured.

The Centers for Disease Control and Prevention recently updated its guidelines for how it determines the risk level of COVID-19 in communities. Instead of relying primarily on the percent of positive tests, the method now emphasizes hospital admissions and occupied beds along with COVID-19 case counts. Meanwhile, demand for COVID-19 PCR tests is falling as more people are using at-home rapid tests, the results of which often aren’t reported to public health agencies.

In the US, all of this has prompted some jurisdictions to scale back COVID-19 testing capacity and contact tracing efforts. “W​e’re at a place where we can focus a little more on severe illness because we have such high immunity in our population, both through vaccination and through recent infection, particularly with Omicron,” says Crystal Watson, a senior scholar at the Johns Hopkins Center for Health Security. 

[Related: The CDC is relaxing indoor mask guidelines and shaking up how it measures COVID risk]

However, this could lead to gaps in our understanding of how widely COVID-19 continues to circulate. “Hospitalizations are a lagging indicator, so it’s really important to maintain surveillance where we can in order to have early warning that a surge is coming and to do surveillance for new variants that might be consequential,” Watson says.

Fortunately, there are several ways that we can continue to keep tabs on the novel coronavirus. What’s more, COVID-19 has galvanized government agencies to invest in new surveillance systems that could be adapted for other diseases down the road, experts say.

Strategic testing

Rather than testing large proportions of the population for COVID-19, public health officials could maintain “sentinel” surveillance sites that are carefully chosen to be representative of the population, Watson says. 

Meanwhile, if and when case counts begin to climb again, it will be easier for communities to increase the availability of PCR testing as needed, says Jeffrey Shaman, a professor of environmental health sciences at the Columbia University Mailman School of Public Health. The widespread use of both PCR and at-home tests is a major improvement compared to the early months of the pandemic. “What we’re seeing now, at least what I hope, is a little more of a fluid capacity to ramp up production again,” Shaman says. 

Another key component of monitoring COVID-19 is to determine the genetic code of the virus present in PCR test samples, a process known as genomic sequencing. This reveals whether a person was infected with Omicron, Delta, or some other version of the novel coronavirus. Right now, only a small fraction of tests are sequenced, Watson says. But researchers would have a better shot at spotting emerging variants if we increased the proportion of samples that undergo sequencing, as other countries such as Denmark have done. 

“We’re kind of switching from trying to track overall prevalence of COVID in a community to more watching for outbreaks, and especially watching for outbreaks from new variants,” says Aaron Packman, director of Northwestern University’s Center for Water Research. 

Surveying sewage

One relatively cheap, anonymous way to do this is testing municipal sewage for the presence of SARS-CoV-2. Remnants of the virus can be found in poop and other human waste. Wastewater surveillance takes advantage of existing sewer systems, captures asymptomatic or pre-symptomatic infections, and has been especially valuable in places where COVID-19 tests aren’t readily available, Packman notes. 

“When cases are low, that can help you understand that something is brewing,” Watson says. “It can be helpful in detecting a new surge [of infections] and helpful in that early detection of new variants.”

[Related: Poop could be the key to tracking COVID-19 outbreaks]

Wastewater surveillance does have limitations, Shaman says. Researchers are still working out how the amount of virus shed along with feces differs from person to person. As it flows through the sewers, the virus may break down before it can be sampled. Human sewage can also be diluted or contaminated with stormwater runoff or waste from animals infected with COVID-19 (or freeze during cold snaps).

“We’re still getting a handle on what we can and can’t do with that kind of information,” Shaman says. 

Packman and his collaborators are working on refining wastewater sampling techniques to pick up lower levels of the novel coronavirus. Similar monitoring efforts are in place around the country, and the CDC launched a National Wastewater Surveillance System in late 2020. 

Wastewater surveillance was already used to track public health issues such as polio before the pandemic. However, Packman says, “It’s only because of the pandemic really that there was this huge information need and this huge push to put wastewater surveillance into place all over the country.” Packman also sees the potential benefits of applying this fecal infrastructure to other concerns like influenza or opioid abuse in the future.

At-home test results matter

At-home COVID-19 tests can also be a valuable source of data, Watson says. “I don’t think most people are aware that they can report [their results],” she says, adding that it will be important to give people ways to privately and easily log positive tests with public health agencies going forward.

Right now, the steps involved in reporting at-home tests to official agencies varies from region to region. It’s a good idea to check your local health department website for instructions on how to share positive test results and notify your healthcare provider if your at-home COVID test turns positive.

[Related: Which at-home COVID-19 test should you buy?]

At-home tests could be useful for tracking other kinds of infectious diseases down the road as well, Watson says. 

“It’s worth putting in the work and the thought as to how we could harness that at-home awareness for the purpose of public health,” she says. Additionally, Watson says, “The more that we can maintain the amazing capacity that we’ve built for testing and surveillance during COVID-19, I think the better off we will be when we face the next infectious disease threat.”

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When horses or cheetahs feel the need for speed, they break into a gait known as galloping. Rabbits bound. Some aquatic animals haul themselves about using forms of locomotion that rely on their fins, known as crutching or punting. All of these motions are special–the timings of left and right footfalls or fins aren’t evenly spaced apart.

Not all animals rely on these sorts of movements to get around quickly. However, so-called asymmetrical gaits aren’t a new innovation among vertebrates, scientists reported on March 8 in the Journal of Experimental Biology. The researchers analyzed observations of movements from hundreds of species and concluded that irregular gaits may have first emerged in ancient fish-like animals even before vertebrates made the journey onto land. The findings suggest that different groups of animals gained and lost the ability to use asymmetric gaits throughout vertebrate history. 

Though it was “more or less” known that land animals independently evolved these motions, “the idea that this ability is ancient for jawed fishes is relatively novel and intriguing,” John Hutchinson, a professor of evolutionary biomechanics at the Royal Veterinary College Hawkshead Campus in Hatfield, England, who wasn’t involved with the research said in an email.

When an animal walks or trots, it moves its limbs in a regular, evenly-timed pattern known as a symmetrical gait. To travel more quickly, many animals can switch to asymmetrical gaits, says Eric McElroy, a biology professor at the ​College of Charleston in South Carolina and coauthor of the findings. One classic example is a horse’s gallop.

In a gallop, all four feet hit the ground at different, unevenly spaced times, McElroy and his collaborator Michael Granatosky, of the New York Institute of Technology in Old Westbury, wrote in the paper. Mammals aren’t the only gallopers; some crocodilians have also been observed using this gait.

Gazelles can achieve another kind of asymmetrical gait called pronking, which involves springing into the air and landing on all four feet simultaneously. Toads and rabbits use bounding or half-bounding gaits, in which the two hindfeet hit the ground at the same time. Mudskippers, sea turtles, and some seals move their front flippers simultaneously in a “crutching” gait to get around on land. Some rays and other fishes punt, moving their pelvic fins simultaneously to scoot along the seafloor.

There are also some vertebrates that don’t seem to use asymmetrical gaits, including lizards, salamanders, platypuses, hedgehogs, lorises, and elephants. 

[Related: We’ve seen how tardigrades walk, and it’s mesmerizing]

To understand when these gaits first appeared, McElroy and Granatosky pored over reports of both symmetrical and asymmetrical movements in 308 different species of gnathostomes, or vertebrates with jaws. The vast majority of present-day vertebrates belong to this group, except for hagfish and lampreys. 

The researchers used computer models to investigate four different evolutionary scenarios. In one, the shared ancestor of gnathostomes had the ability to move asymmetrically, and its descendants could lose this ability but not regain it. Another model assumed that the trait could only be gained, which implied that the gnathostome ancestor didn’t have an asymmetric gait. 

In the third model, asymmetric gaits showed up and disappeared at roughly equal rates across the family tree. The fourth model removed the rate constraint. This allowed organisms to “have really fast evolution of asymmetrical gaits and really slow losses of asymmetrical gaits,” McElroy says. “They can be super different in terms of the speed of evolution.” 

He and Granatosky found that this fourth scenario was the most likely, based on how asymmetrical gaits are distributed across modern vertebrates. They calculated that the gnathostome ancestor had a roughly 75 percent probability of using some sort of asymmetrical gait.

This fish-like creature likely inhabited shallow coastal seas 400 million to 450 million years ago, around 25 million to 100 million years before some of its descendants invaded the land. The gnathostome ancestor may have used its fins to crutch or punt itself over the seabed, McElroy says, noting that many fossils of early jawed vertebrates resemble present-day fish that use these motions such as skates and rays. 

The team also determined that the ancestor that gave rise to modern mammals likely had the ability to move asymmetrically, while the ancestors of amphibians and lizards probably did not.

It’s unclear why asymmetrical gaits were lost in some groups of vertebrates. Elephants may be too large to gallop without putting dangerous amounts of stress on their bones. Certain animals, such as lorises and many turtles, may never move fast enough to need asymmetric gaits. 

Lizards can scurry along very quickly without moving their limbs in an asymmetrical pattern. “I’ve never seen a lizard gallop, and it’s weird that they don’t do it and suggests some sort of neuromuscular constraint,” McElroy says. “I’d like to take a closer look at that to really figure out are lizards just not capable of doing this, or is it something that they do very, very rarely, or there are some groups of them that can do it and we just haven’t studied those groups?” 

The 308 present-day animals that the researchers examined represent only a fraction of the estimated 69,000 vertebrate species. This, Hutchinson said, might have skewed the results of the analysis. 

Observations of modern fish species were relatively sparse, McElroy acknowledges. “Fish are going to tend to have a larger effect on the [evolutionary] reconstructions because they’re the oldest species,” he says, and represent “both a limitation and an area for future discovery.” Accounting for the locomotion of extinct vertebrates would improve these estimates, too, but little is known about how they moved.

Despite these limitations, Hutchinson said, “the study is valuable in that it synthesizes a lot of data with good evolutionary tools and will provoke further investigations into the questions it raises.”

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A tiny frog with an impressive snout has been discovered in the Peruvian Amazon, scientists reported this week. 

The frog makes its home in the basin of the Putumayo River, which runs through Colombia, Ecuador, Peru, and Brazil. Researchers found the new species during a 2019 expedition to learn more about the basin’s mysterious amphibian residents. The frog’s most distinctive feature is a long, protruding snout resembling that of a tapir, a pig-like, hoofed mammal with a distinct trunk. The shape of the frog’s schnoz may hint at a life spent nosing through soft, wet soils.

The newly-recognized amphibian is also a smooth, rich brown in color. “It looks like it was made from chocolate,” says Germán Chávez, a herpetologist at Peru’s Instituto Peruano de Herpetología who is based in Sheffield, England.

The team was only able to capture three of the tapir frogs. Much remains to be learned about the species, including its range and population status, says Chávez, who described the new frog on February 16 in the journal Evolutionary Systematics.

The first tapir frog he spotted was a young male less than a third of an inch long. Several nights later, the researchers heard a high-pitched beeping coming from beneath the ground, which led them to two slightly larger adult males. When the team analyzed the frogs’ anatomy and genetic material, they confirmed that the amphibians were a previously unreported species belonging to a group known as disc frogs. Disc frogs spend a lot of time underground, making them difficult for scientists to detect and study.

Chávez and his collaborators were guided to the frogs’ moist habitat by guides from Peru’s ​​Comunidad Nativa Tres Esquinas. The first time that local people and several of the researchers saw one of the frogs, they referred to it as “rana danta”—the Spanish terms for “frog” and “tapir,” respectively. “When we found these individuals, they mentioned, ‘Oh there’s one of those tapir frogs,’” Chávez recalls. He and his colleagues named the new species Synapturanus danta in honor of the long-nosed mammals, which mostly live in the forests and grasslands of Central and South America.

Most disc frogs have a bulky body and broad snout that helps with burrowing into the soil, while the tapir frog has a more slender frame. “The danta frog is not prepared to dig very hard because the body shape is not robust enough,” Chávez says. However, its body is perfectly suited to the soggy and loose soil of the peatlands in which it dwells. In this type of wetland, the damp conditions cause partially-decayed plant matter called peat to accumulate. Chávez and his colleagues observed the tapir frogs in the shallow spaces beneath the roots of small trees growing from the least waterlogged patches of peat. 

A team of Peruvian herpetologists has recently identified another group of frogs elsewhere in the Putumayo basin that may turn out to be the same species, he says. If this population can be confirmed as tapir frogs, they could give scientists more information about the species’s distribution and how best to conserve it. 

The Putumayo is the only remaining Amazon tributary with no existing or proposed dams, the researchers noted in the paper. Currently, the area where the species was discovered has not been heavily affected much by habitat destruction. However, the amphibians could help researchers understand how this wetland ecosystem is responding to deforestation or climate change in the future.  

The next step, Chávez says, will be to determine whether the tapir frog is restricted to the peatlands. “If we could prove that this frog is a peatland specialist…we could consider the danta frog as an indicator of a healthy peatland,” he says. 

The variety of approaches the researchers used, which included anatomical observations, genetic data, and audio recordings, strengthens their conclusion that the tapir frog is a new species, says Anne Chambers, an evolutionary biologist at the University of California, Berkeley, who wasn’t involved in the research.

“In terms of this region, we know that there’s a lot of undescribed species and undescribed diversity in that part of the world,” she says. “It’s important for us to try to efficiently describe these species in a scientific and reliable way.”

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The dinosaur-killing asteroid that smashed into present-day Mexico 66 million years ago arrived in springtime, a new analysis suggests.

Scientists examined fossilized fish that perished shortly after the impact and used the growth patterns and chemicals preserved within the bones to pin down the timing of the event. The researchers concluded that the asteroid strike occurred during spring in the Northern Hemisphere, a time when many animals would have been raising young and especially vulnerable to the cataclysm. The season in which the asteroid made contact likely influenced which species survived the mass extinction that followed, the team reported on February 23 in Nature.

“The results of this study may help explain why some organisms went extinct at the end of the Cretaceous while others weathered the catastrophe,” Michael Donovan, a paleobiologist at the Cleveland Museum of Natural History who wasn’t involved in the research, said in an email. 

The asteroid’s immediate aftermath included forest fires, tsunamis, and rocky fallout that reached areas more than 2,000 miles from the Chicxulub impact crater in Mexico’s Yucatán Peninsula. One site that preserves evidence of these disturbances is the Tanis event deposit, which lies within the fossil-rich Hell Creek Formation in North Dakota.

Within tens of minutes after the asteroid impact, a seismic shockwave would have shaken the Tanis river and created a surge of water that hurled fish, ammonites, and other marine creatures ashore. Meanwhile, fragments of molten and vaporized rock called spherules, which were blasted into the atmosphere and resolidified, rained down upon the unfortunate animals as they were buried alive. 

“The shockwave moves very fast through the Earth’s crust and causes huge waves in the overlying bodies of water (lakes, rivers); very similar to a pool during an earthquake,” Melanie During, a PhD student in vertebrate paleontology at Uppsala University in Sweden and coauthor of the findings, said in an email.

To determine when this turmoil took place, During and her collaborators examined filter-feeding paddlefishes and sturgeons found in the deposit with spherules caught in their gills. Micro-CT scans of one of the skeletons revealed that the rock fragments hadn’t yet reached the digestive tract, confirming that the fish died very soon after impact. 

The researchers also peered at fine slices of the fishes’ fin spines and jawbones under the microscope. These bones grow similarly to trees, During said, adding a new layer every year. 

She and her team observed the tiny pores in each layer that once housed bone cells, which grow in size and density during the warm months when food is plentiful. “[We] saw that all these fishes recorded seasonality and died exactly at the same time: Spring,” During said.

The researchers next analyzed how the different types of carbon atoms, or isotopes, in the growth rings varied throughout the year. The fish receive “heavier” carbon isotopes from tiny creatures called zooplankton they dine on. When the fish died, the ratio of heavy carbon isotopes to lighter ones was increasing but hadn’t quite reached its typical summertime peak. This provided another piece of evidence that the fish met their end during the spring. 

“The actual extinction took far longer than just this moment itself,” During acknowledged. But the catastrophic season—spring in the Northern Hemisphere, and fall in the Southern one—would have eliminated many organisms even before the asteroid’s fallout enveloped Earth in nuclear winter, she said.

For many organisms, spring is the prime season for growth and reproduction after the harsh winter months, During said. As a result, the effects of the environmental devastation that followed in the asteroid’s wake may have been magnified for life in the Northern Hemisphere, Donovan added. 

Plants and animals in the Southern Hemisphere, which was in the midst of autumn, might have fared better; the asteroid arrived at a time when mammals were preparing to hibernate in burrows and insect pupae and dormant seeds were tucked away in the soil. 

[Related: June was probably a terrible month to be a dinosaur. Here’s how we know.]

Donovan and other researchers have previously reported that ecosystems in the Southern Hemisphere may have recovered more quickly from the mass extinction unleashed by the asteroid than Northern ecosystems. The new study may help explain the difference, he said, although many questions about this harrowing period remain.

“Were differences in regional recovery patterns a result of the distance from the asteroid impact site, variation in local climates, the season during which the impact occurred, or some combination?” Donovan said.

As researchers continue to investigate how the extinction that wiped out the dinosaurs unfolded across the planet, During said, one challenge is the relative scarcity in data from the Southern Hemisphere.  

There has been a “tremendous bias” toward studying this event from fossil finds in the Northern Hemisphere, with many more gaps in Southern Hemisphere data, During said. “It is absolutely worth it to concentrate on extracting more fossils from the Southern Hemisphere,” she said, “and doing so by including and supporting the local researchers who often lack funding to do their research.”

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As the pandemic enters its third year, the COVID-19 vaccines developed by Moderna and Pfizer continue to dominate vaccination efforts in the US. Only 3.34 percent of shots administered in the country have used Johnson & Johnson’s formula. However, many less wealthy nations like Mexico, Vietnam, and Zambia have relied on the J&J shot. 

On February 8, the New York Times reported that the only facility making usable batches of J&J’s COVID-19 vaccine shut down production and switched to manufacturing a drug for another respiratory virus late last year. The plant, which is located in the Dutch city of Leiden, is expected to resume making the vaccines next month. But the pause raised concerns about accessibility for people in regions where few have been vaccinated against COVID-19. Nearly 40 percent of the world’s population is still unvaccinated, even as more than 92 million Americans have received a booster shot.

“The article came as somewhat of a surprise given that the world has not been vaccinated yet, and that was supposed to be the vaccine that had greater reach out there,” says Deborah Fuller, a vaccinologist at the University of Washington School of Medicine in Seattle. However, she added, the move is not necessarily cause for alarm. The number of COVID-19 shots that have received emergency authorization or full approval around the globe continues to grow. What’s more, there are other kinds of vaccines out there with the same advantages as J&J’s, while being easier to mass produce.

“To stop the pandemic it’s not going to take one type of vaccine, but multiple different types of vaccine that fulfill different sorts of requirements,” Fuller says. “What’s starting to happen with the J&J vaccine is that the unique part of its bubble is shrinking because other things are going to come into play.”

[Related: The 5 phases of COVID’s endgame]

More than two dozen different COVID-19 vaccines are in use around the world, and more than 100 are being tested in clinical trials. These vaccines use a variety of strategies to train the immune system to recognize and attack the novel coronavirus and its variants. 

Some vaccines, including the ones produced by Moderna and Pfizer, contain genetic material that codes for the spike-shaped protein that helps the virus infect host cells. The recipient’s own cells use these instructions to build copies of the coronavirus protein, which then rouse the immune system without causing disease on their own.

Meanwhile, so-called viral vector vaccines, including those from J&J and the University of Oxford and AstraZeneca’s collaboration, use a different virus engineered to carry the coronavirus genes as a delivery vehicle. Other vaccines contain proteins from the coronavirus or copies of the pathogen that have been weakened or “killed” so they can’t make the recipient sick. Other vaccines contain proteins from the coronavirus, which is also how common immunizations against Hepatitis B and human papillomavirus work. Still others contain copies of the pathogen that have been weakened or “killed,” so they can’t make the recipient sick, much like the chickenpox and inactivated polio vaccines.

The mRNA-based shots developed by Moderna and Pfizer have shown the most impressive results when it comes to preventing symptomatic COVID-19. The J&J formulation has also been linked with rare but serious effects. However, all three are very effective at preventing serious illness from Omicron and other variants, Fuller notes. 

The J&J shot also comes with a few advantages of its own. Unlike mRNA vaccines, it doesn’t require ultra-cold storage conditions—and it’s given as a single shot, rather than two shots spaced several weeks apart. These characteristics made the vaccine easier to distribute, particularly to people who lived in remote areas. 

“We have to give J&J credit where it’s due, that it fulfilled an important need very early in the pandemic,” Fuller says. “There’s no doubt in my mind that it saved a lot of people and encouraged some people who may not have been willing to take the mRNA vaccine early on to at least start getting vaccinated.”

[Related: Just had COVID? Here’s when you should get a booster.]

Jake Sargent, a spokesperson for Johnson & Johnson, told the New York Times that the company has millions of doses of the COVID-19 vaccine in inventory and will continue to meet its obligations to organizations that have put in orders on behalf of low-income nations. Lauren Plumer, another spokesperson for the company, also emphasized J&J’s commitment to provide the vaccine to low- and middle-income nations in an email to PopSci. “Global equity has been at the forefront of Johnson & Johnson’s response since the onset of the COVID-19 pandemic,” Plumer wrote. The company continues to work toward a licensing agreement with Aspen Pharmacare in South Africa to allow the group, which currently packages the vaccine, to manufacture and sell it, Plumer added. 

Several protein-based COVID-19 vaccines are already available in Russia, South Korea, the UK, and other countries. A number of other formulations have entered phase 3 clinical trials, including one developed by Sanofi and GSK in the same design as the influenza vaccine Flublok. These immunizations may increasingly fill the same niche as J&J’s shot, Fuller says, making the pause in production less concerning.  

“I’m not as worried about that as I would have been six months ago, when the [protein] vaccines were still some months away from being potentially useful in terms of vaccine distribution,” Fuller says. “That’s a tried and true technology that’s out there. All over the world there are already facilities capable of manufacturing these vaccines locally.”

However, protein-based vaccines take a long time to develop. Researchers use engineered bacteria, yeast, or insect cells to produce the viral proteins. “Then once you produce it, you have to purify it … and then you have to go through quality control to make sure that the structure of the protein is intact,” Fuller says. “It goes through a long process to ensure that it’s a pristine product before it can actually go into people.” 

[Related: Why are kids’ immune systems different from adults’]

These steps aren’t necessary for mRNA and viral vector vaccines, which means they can be developed more swiftly. Because of the lengthy development process for protein-based vaccines, Fuller says, it will be particularly important for vaccine makers to ensure that their formulations provoke a robust immune response that will hold up against Omicron and future variants of the novel coronavirus. Still, she says, as more protein-based shots become available, COVID-19 vaccination rates across the world could rise very quickly.

“We have some exciting new vaccines coming,” Fuller says. “It’s a slow wheel that takes a long time to get going, but once that wheel gets going, that thing just churns out vaccines like nobody’s business.”

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Bald and golden eagles across North America are in danger from lead poisoning, a new analysis suggests. 

Researchers tracked levels of the deadly metal in more than 1,000 eagles from 38 US states, and found that “unexpectedly high” proportions of birds from the two species suffered from both chronic and recent poisoning. Almost half of the eagles the team inspected showed signs of repeated lead exposure in their bones, raising concerns about the impacts on bald and golden eagle populations around the continent. The findings can inform future eagle conservation efforts, the researchers reported on February 17 in Science.

“For quite some time we have known that lead poisoning was affecting these species, especially as we have seen case numbers increase in rehabilitation settings,” Megan Judkins, the aviary director at the Grey Snow Eagle House, an eagle rehabilitation facility in Perkins, Oklahoma run and operated by the Iowa Tribe of Oklahoma, said in an email. “But research like this allows us to see this for what it is, more than just a localized problem.” 

She and her colleagues were not involved in the new study, but have also observed lead poisoning cases drastically increase within the last five to 10 years, said Judkins, who researches eagle genomics at Oklahoma State University. 

Although lead occurs naturally in Earth’s crust, it also gets into the environment through human activities such as mining. Eagles are frequently exposed to the metal through lead bullets, which can fragment into hundreds of pieces when they strike an animal, says Vincent Slabe, a coauthor of the study and research wildlife biologist based in Montana who works for the nonprofit Conservation Science Global Inc. Once ingested, lead damages the birds’ nervous systems and organs and can lead to seizures, extreme weakness, and death. Even if a bird survives, it may experience lifelong vision, cardiovascular, and other health problems, Judkins said.

[Related: Everything you think you know about bald eagles is wrong]

To find out how wide ranging the issue is, the team reached out to scientists studying live eagles, state and federal agencies that respond to reports of dead eagles, and wildlife rehabilitation facilities that treat sick and injured birds. Between 2010 and 2018, the researchers examined 1,210 eagles, including 620 live birds. 

The researchers sampled a variety of tissues, including blood, bones, liver, and feathers. While lead can linger in the blood or liver for weeks to months, it accumulates in bone throughout an animal’s lifetime.

“Basically all of these data are telling us the same story: These eagles are very frequently exposed to lead, more than we had previously understood, and this exposure is happening repeatedly over the course of their lives,” says Todd E. Katzner, a research wildlife biologist at the US Geological Survey Forest and Rangeland Ecosystem Science Center in Boise, Idaho and another study author.

He and his team measured lead levels in the birds’ bones indicative of chronic poisoning in 46 and 47 percent of the deceased golden and bald eagles, respectively. The other tissues carried evidence of short-term lead exposures in 27 to 33 percent of bald eagles and 7 to 35 percent of golden eagles. Adult birds of both species carried higher bone lead concentrations than younger birds. 

The researchers also detected higher rates of chronic lead poisoning in bald eagles from central states than those closer to the coasts, although the reasons for this pattern aren’t yet clear, Slabe says.

Generally, lead concentrations in the blood and livers of both species rose during the winter months, when the eagles typically rely on scavenging to sustain themselves. The birds often feast upon gut piles left behind by hunters and can ingest fragments of lead ammunition along with the nutritious meat. 

“The eagles are being poisoned during the time of year when these carcasses are abundant on the landscape,” Slabe says. “This realization has been concluded from multiple regional studies, and now concluded as a source of lead exposure in these birds at the continental scale in our study.”

He and his colleagues found that 4.9 percent of dead golden eagles and 25.8 percent of dead bald eagles had lead concentrations in their livers high enough to indicate severe poisoning. Based on these numbers, the team calculated that deadly lead poisoning may be reducing annual population growth rates by 3.8 percent in bald eagles and 0.8 percent in golden eagles. That’s especially worrying news for golden eagles, whose populations are holding steady or declining even as bald eagles grow in number.

“Over a 20-year period…the population will be smaller by many thousands of individuals than it would be otherwise,” Katzner says. 

Lead may also threaten eagle populations in ways that the researchers didn’t account for, he adds. Even when lead poisoning isn’t fatal, it may weaken birds enough to prevent them from laying eggs and raising chicks.

The team is now investigating whether fewer eagles die after hunters switch to using non-lead ammunition.

“​​The more animals they harvest with non-lead ammo, the more non-leaded food there is for eagles on the landscape,” Slabe says. “As we switch more of this food source to a clean meal and a healthy meal for an eagle, then we could start to see this pattern changing [to] a reduction in mortality in bald and golden eagles from lead poisoning at a nationwide scale.” 

The new report provides important information for both management decisions and public outreach, Judkins said.

“Fortunately, by utilizing non-lead ammunitions, we can easily eliminate the chance for these individuals to ingest lead,” she said. “By being able to include a strong, peer-reviewed paper such as this into our educational tools, it makes our statement that much stronger.”

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In 2010, three patients received an experimental form of immunotherapy for leukemia through a clinical trial at the University of Pennsylvania. Two of the patients went into complete remission—and stayed that way. 

The treatment, known as CAR T-cell therapy, is now FDA-approved to treat certain blood cancers. It involves engineering a patient’s own white blood cells to attack cancerous cells and then returning them to the body. Since clinical trials and FDA approval, CAR T-cell therapy has already been used to successfully treat and clear certain cancers. However, CAR T-cell therapy doesn’t lead to lasting remissions for every patient, and it can cause serious side effects. A new report offers clues about why the treatment is sometimes remarkably effective.

The two patients who responded well to CAR T-cell therapy in 2010 remained disease free for over a decade. One of the men, a Californian named Doug Olson, is now 75. The other, William Ludwig, died early last year of COVID-19. Researchers were able to detect CAR T-cells lingering in Olson and Ludwig’s bloodstreams long after their cancers disappeared, although the types of immune cells that persisted were slightly different than anticipated, the team reported on February 2 in Nature.

“Now we can finally say the word ‘cure’ with CAR T-cells,” Carl June, the principal investigator for the University of Pennsylvania trial, told The New York Times.

Olson and Ludwig were among the earliest recipients of CAR T-cell therapy, allowing clinicians a chance to track the patients’ cells and condition over the past decade. “To use the word ‘cure,’ you really need a long time to follow up to make sure people don’t relapse,” says David Maloney, the medical director of cellular immunotherapy at the Immunotherapy Integrated Research Center at the Fred Hutchinson Cancer Research Center in Seattle. “When we get these people out to 10 and 11 years post-treatment, that encourages us to be a little more forceful in saying that perhaps patients are cured in some cases.”

Steven Rosenberg, chief of the surgery branch at the National Cancer Institute’s Center for Cancer Research, is a little more hesitant about making similar declarations. He and his colleagues treated the first person to receive CAR T-cell therapy—a man with advanced lymphoma—in 2009; like Olson and Ludwig, the patient underwent a complete remission and has stayed disease-free. Still, it’s not impossible for a person’s cancer to come back after such a long time, Rosenberg says. 

While it may be too soon to know for certain that these patients are cured, Rosenberg feels, these cases are all very encouraging. “I think it’s a good step in that direction,” he says. “It certainly can last a very long time and provide a relatively normal life back to these patients.”

A living drug

Immunotherapy treatments harness a person’s immune system to fight cancer. The white blood cells known as T-cells, which form the basis of CAR T-cell therapy, play a variety of roles in the immune system, including attacking cells that have become infected by viruses or turned cancerous. However, the T-cells a person’s body makes naturally may not be equipped with the recognition tools, or may be too few in number, to vanquish their cancer.

The goal of CAR T-cell therapy is to genetically modify T-cells so they can effectively destroy cancerous cells. T-cells are edited to produce a lab-designed protein called a chimeric antigen receptor, or CAR, on their surface. The CAR is tailored to the type of cell that has gone awry. “[You] essentially insert a gene that could make all of the T-cells recognize the same thing,” Maloney says.

[Related: Why immunotherapy could be the cure to cancer we have all been waiting for]

For the clinical trials in 2009 and 2010, Rosenberg’s team and the University of Pennsylvania researchers independently engineered CAR T-cells that home in on a molecule called C19 that’s found on antibody-making B-cells—another immune cell known to become cancerous in certain leukemias and lymphomas. After being administered, the disease-fighting T-cells can multiply by up to 10,000 times over the course of several weeks, Rosenberg says. The patient is treated with their own cells.

“It’s a living drug,” Rosenberg says. “They can survive in the body for years, and they appear to be able to mediate complete, durable [remissions].”

CAR T-cell therapy is now used to treat certain forms of leukemia, lymphoma, and multiple myeloma. But, as the Times noted, it’s more effective against some blood cancers than others. Some people who go into remission later relapse. 

To understand why CAR T-cell therapy was so successful for Olson and Ludwig, June and his colleagues investigated the fate of the modified cells. “The surprising thing is that the types of CAR T-cells that actually persisted seemed to be slightly different than what people were anticipating would be the ones that would result in a long-term population,” Maloney says.

The cells that stuck around weren’t the so-called “killer” T-cells that attack diseased cells, but rather “helper” T-cells that are typically involved in coordinating the immune response. Laboratory experiments suggested that, intriguingly, these helper CAR T-cells retained their cell-killing ability. 

“We have long realized that there must be differences between CAR T-cells that persist for long periods and those that die within weeks to months from exhaustion,” John E. Levine, a professor of medicine, hematology, and medical oncology and of pediatrics at the Tisch Cancer Institute at Mount Sinai in New York, said in an email. “This paper now defines some of those differences.”

The reason for the lasting response, he said, may be that the CAR T-cells are kept stimulated by the B-cells constantly being made in the bone marrow. “These B-cells provide an endless source of targets for the few CAR T-cells that have the potential to stay healthy and live a long time,” Levine said. 

The results could help researchers identify CAR T-cell traits to emulate in the future. “This will lead to a lot of additional work to see how these cells arise and evolve over time after they’re infused,” Maloney says, adding that research clinicians could “potentially make cells that have these characteristics that might be associated with better outcomes.”

Another possible avenue for CAR T-cell research is to recreate the conditions that set these immune warriors up for success when they don’t occur naturally. For example, Levine said, researchers could “provide an artificial source that mimics the constant stimulation of CAR T-cells that seems to help keep them surveilling for malignant cells.”

Understanding more about how these treatments work could ultimately lead to patients receiving CAR T-cell therapy without having to wait until several other lines of treatment have failed. “As we get more data [and] we know how safe they are, we know how effective they are, we can start moving them up, and the future may be that this will be used much earlier in the course of cancer therapy than where we’re currently using them,” Maloney says.

Broadening the approach

One major drawback of CAR T-cell therapy is that it hasn’t been proven effective against solid tumors found in places like the colon, stomach, prostate, breasts, and uterus, which cause about 90 percent of cancer deaths in the US, Rosenberg says.

There are several reasons for this: “It’s a hostile environment, where the tumor is trying to kill the T-cells and trying to keep the T-cells out of the tumor so they…can’t actually get in there and attack the cancer,” Maloney says. Researchers are working on strategies to make T-cells more resistant to these blocking efforts, he says.

Another problem is that CAR T-cells kill healthy cells along with cancerous ones. When CAR T-cells demolish B-cells in people with blood cancers, the immune system can become more vulnerable to infections. To help avoid this, patients can receive antibody infusions and their antibody-making B-cells may replenish over time, Rosenberg says. 

With solid tumors it’s a different story. “You can live without B-cells during that interim by getting immunoglobulin infusions, whereas if you wipe out a liver or a lung or a heart or a brain, you can’t survive,” he says.

Fortunately, solid tumors are often somewhat vulnerable to naturally occuring T-cells, which recognize abnormal proteins specific to these cancerous cells. “The DNA in the normal cells has mutated in these solid cancers…and it turns out it’s the products of those mutations that conventional T-cells recognize,” Rosenberg says.

He and his colleagues have spent several decades investigating treatments that are similar in principle to CAR T-cell therapy to fight solid cancers.

One approach involves identifying which T-cells are best at recognizing a person’s cancer, multiplying these tumor-invading cells to much greater numbers in the lab, and transferring them back into the patient. Melanoma is a particularly appealing target for this treatment because it tends to have many mutations for T-cells to recognize. However, the experimental therapy shows promise for other types of cancer as well, including metastatic breast cancer.

The team is also testing techniques aimed at patients who don’t mount a strong enough immune response on their own. T-cells from these people are engineered to carry lab-made versions of naturally occurring T-cell proteins that will recognize mutations found on their cancer, much like CAR T-cells are equipped with synthetic proteins. 

These treatments can be more complicated to implement than CAR T-cell therapy because the T-cells recognize solid tumors by mutations that differ from one patient to the next, rather than a common molecule like CD19. “It’s a very highly personalized treatment, but we’ve shown it can be effective,” Rosenberg says. “The major challenge that we face now is increasing it from isolated cases to treatments that can be widely administered.”

The treatments he and his team are working on and CAR T-cell therapy are all forms of adoptive cell therapy, a branch of immunotherapy that involves multiplying or engineering immune cells from a patient to fight their cancer. The most promising avenue for adoptive cell therapy, Rosenberg feels, will be against the solid tumors in the future

“This entirely new approach of creating a drug for the patient using their own cells has resulted in these dramatic long-term responses that have returned people from being very ill to normal life and certainly is here to stay,” Rosenberg says.

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Around 150 million years ago, a long-necked dinosaur in southwest Montana became very ill. The unfortunate sauropod might have endured a sore throat, headaches, and difficulty breathing. 

Although the dinosaur in question is long dead, signs of this sickness are preserved in its neck bones as lumpy growths. These abnormal structures may have been caused by a fungal infection similar to those seen in birds today, a team of paleontologists, veterinarians, and other anatomy specialists have determined. The growths represent the first evidence of a dinosaur respiratory infection and could shed light on certain aspects of dinosaur physiology, the team concluded on February 10 in Scientific Reports.

“I’ve looked at sauropods from all over the world and I’ve never seen a feature like this before,” says Cary Woodruff, the director of paleontology at the Great Plains Dinosaur Museum in Malta, Montana and a couthor of the findings. “It helps us understand the world that these dinosaurs were in—what kinds of illness and diseases plagued the tyrant lizards.”

Many of the ailments that struck dinosaurs are likely to remain a mystery because they left no trace on the bones. However, paleontologists have found fossil evidence of a host of maladies ranging from tooth infections to broken bones, arthritis, and cancer.

The dinosaur that Woodruff and his team examined was originally discovered in 1990 and nicknamed “Dolly” in honor of Dolly Parton. The fossil is similar in appearance to diplodocus, another long-necked herbivore that lived during the Late Jurassic. Dolly was probably between 15 and 20 years old when it died and reached a length of around 60 feet.

[Related: Duck-billed dinosaurs had the same bone tumors as people]

When Woodruff and his colleagues examined Dolly’s vertebrae, they noticed something odd.

Dinosaurs share numerous anatomical features with their living avian relatives and are thought to have breathed similarly to birds, he says. The respiratory system is more efficient in birds than mammals, with extra air sacs in the lungs and structures that penetrate into the bones. Dinosaurs also have sockets where respiratory tissue connects to the bone known as pleurocoels. “I like the analogy of a vacuum cleaner,” Woodruff says. “The respiratory tissue is like the hose, the bone is like the vacuum canister, and where that hose joins into the vacuum is the pleurocoel.”

Normally the bone in this region is very smooth. But in Dolly, the edges of pleurocoels on both the left and right sides of multiple vertebrae were knobbly and rough—a bit like a fossilized piece of broccoli. “Sticking out of it was this really gnarly, lumpy, irregular abnormal bone growth,” Woodruff says. “That was the smoking gun that this is not normal.”

To understand what might have caused the growths, he and his team searched for similar disorders among Dolly’s closest living relatives: birds and crocodilians. In crocodilians, the respiratory tract is “not as developed” as in birds, Woodruff says, and the respiratory tissue doesn’t pervade the bones. However, birds can develop respiratory infections that spread to the bone in the same location as Dolly’s lesions. 

To narrow down the type of infection Dolly suffered from, the researchers took CT scans of the afflicted vertebrae. In modern birds, some respiratory illnesses cause rind-like growths to develop on the outside of the bone. But in Dolly, the scans suggested, the interior of the bones was also “really screwed up,” Woodruff says. 

Unsurprisingly, no present-day ailments offered a perfect match for the ancient reptile’s growths. However, Dolly’s condition was most consistent with a very common infection called aspergillosis, which develops when birds, and humans, breathe in certain fungal spores. 

By the time such infections reach the bone, they’ve already had plenty of time to wreak havoc on the lungs and associated tissues. Birds with aspergillosis often cough, develop fevers, and lose weight. If a sick bird doesn’t receive treatment, the disease can lead to deadly pneumonia, much as COVID-19 does in people. 

All in all, Dolly would have felt pretty crummy. 

“We can’t say if Dolly just keeled over because of this disease, or just being so visibly sick or on its own from the herd was an easy target for predators,” Woodruff says. “But we can say in one way or another it ultimately caused the death of this animal.”

While Dolly probably didn’t have quite the same disease seen in today’s birds, its bony growths support the idea that dinosaurs were susceptible to fungal respiratory infections and may offer insights about how their immune systems worked. “Mammals and birds have very different immune systems, so if we have this non-bird dinosaur that was breathing like birds and has a bird-like respiratory infection, odds are its immunological response was much more like a bird than mammals or other reptiles,” Woodruff says.

The findings open up a “whole new dimension” in our understanding of dinosaur diseases, while providing a new insight into the musculoskeletal system of sauropods, says Ali Nabavizadeh, a comparative anatomist and paleobiologist at the University of Pennsylvania School of Veterinary Medicine who wasn’t involved with the research. Dolly’s infection also reinforces connections between dinosaurs and modern bird anatomy.

“This paper provides yet another piece of evidence to show just how modern dinosaurs—the birds—are biologically so similar to their extinct non-avian dinosaurian relatives, even to the point of showing similar diseases,” he said in an email. 

In the future, searching for similar lesions in sauropod vertebrae in collections around the world might reveal how prevalent respiratory infections were in these dinosaurs, Nabavizadeh said.

“I am excited to see how these findings can improve upon our knowledge of respiration as well as circulation in these breathtakingly enormous creatures.”

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Fiddler crabs and snapping shrimp rely on enlarged claws to impress or fight off members of their own species—and the bigger the weapon, the better the odds of winning over a mate. But large appendages can be a real energy drain. 

“[It’s] this kind of slow burn of a cost that happens all the time,” says Jason Dinh, a PhD candidate in biology at Duke University.

However, Dinh has found that these crustaceans have developed a trick to bulk up without spending too much energy. When he examined claws from fiddler crabs and two snapping shrimp species, Dinh observed that larger claws contained relatively more exoskeleton and less soft tissue than smaller ones. Chitin, the main ingredient in arthropod exoskeletons, is much less “expensive” to maintain than muscles, nerves, and blood.

“It turns out that one of the ways that they’re able to bear those [metabolic] costs is to build their weapons cheaply: to invest disproportionately more into the cheap stuff compared to the more expensive muscles,” says Dinh, who reported the findings on February 8 in Biology Letters. 

Shrimp and crabs may not be the only creatures to use this strategy. Across the animal kingdom, animals rely on a wide variety of weapons to intimidate rivals, from claws to horns, tusks, and antlers. Generally, large individuals have more spare energy to draw upon than smaller members of their species, which means they can grow hefty weapons that comprise more of their overall body mass, Dinh says. 

[Related: Blood, death, and eye gouging: welcome to the world of acorn woodpeckers]

The difference is particularly striking in fiddler crabs. Male fiddler crabs use an oversized claw to attract females and to duel other males for territory and mates. Petite crabs have claws that only weigh 35 percent of their body mass, while large crabs have claws that make up more than half their body mass. 

“That’s like a boxing glove that’s half your body weight,” says Ummat Somjee, an evolutionary biologist at the Smithsonian Tropical Research Institute in Panama who wasn’t involved in the research. “It’s a really, really extreme investment, and it has been a puzzle for a long time how they can possibly maintain the physiology to maintain these structures.”

Snapping shrimp, on the other hand, deploy their weapons differently. Both males and females have an enlarged claw that produces one of the fastest movements known in nature, Dinh says.

“They basically cock their claw open and then close it really quickly, and their claw shoots out this jet of water that moves incredibly fast and literally boils a small region of water behind the jet,” he says. “When that bubble collapses, it makes a really loud snap.”

Dinh and his collaborators collected hundreds of fiddler crabs and shrimp from salt marshes and oyster reefs in North Carolina and weighed the deceased crustaceans’ bodies and claws. Dinh then weighed the claws again after exposing them to an enzyme that digested the soft tissue, including muscle, while leaving the exoskeleton intact. “That lets us separate the mass of this animal into its expensive digested soft tissues and its less expensive undigested hard tissues,” he explains.  

Across all three species, as the claws increased in size, they contained proportionally more hard exoskeleton and less soft tissue. “The differences were pretty drastic,” Dinh says, noting that the largest male fiddler crabs wielded claws that contained less than half the percentage of muscle mass seen in smaller claws. 

[Related: This 90-million-year-old crab had the eyes of a hunter]

Dinh also found evidence that, while it’s easier for large individuals to build oversized weapons, even small crustaceans can benefit from investing in low-maintenance exoskeleton. With the exception of females from one snapping shrimp species, individuals that sported larger-than-average claws for their body size tended to pack less soft tissue into the exaggerated weapons.

Jumbo-sized claws may deter rival crustaceans, but their intimidating size isn’t the only thing that’s impressive. In fiddler crabs, large claws can pinch harder than small ones, despite having proportionally less muscle. 

It remains to be seen whether oversized claws come with any trade-offs for the snapping shrimp. To produce their ultrafast movements, the crustaceans use their claws like a spring. “The muscles are only there to load the spring; the thing that’s actually closing the claw is the spring itself,” Dinh says. He’s currently investigating whether shrimp and crabs with exaggerated weapons are indeed more successful fighters.

In future research, Dinh would like to investigate how common massive, energetically cheap weapons are in other kinds of animals. Somjee says the claws described in the new report fit the patterns he’s observed in several kinds of insects.

“This might be a pretty wide-ranging phenomenon,” says Somjee. “It’s not necessarily that these animals can invest in these large traits and are paying super high costs for them, it’s that they have found cheap ways to have really big traits.”

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Future hurricanes will bring more extreme flooding to coastal cities in the eastern United States due to a double hit from worsening storm surge and heavy rainfall, scientists reported on February 3 in Nature Climate Change.

The researchers simulated how climate change could alter the impacts of tropical cyclones through the end of the 21st century. They found that the combined frequency of intense storm surge and rainfall that clobbers the coastline may increase by seven to 36 times in the southern US and 30 to 195 times in the Northeast. 

“The results that are presented in the paper give us a pretty good idea of what to possibly expect in the future,” says Thomas Wahl, a coastal engineer at the University of Central Florida who wasn’t involved in the research. “There will likely be a pretty dramatic change in…the likelihood that different flooding drivers occur simultaneously.”

Since 1880, climate change has caused the average global sea level to rise by about 8 to 9 inches. Additionally, climate change is altering the intensity, size, track, and frequency of hurricanes, says Ning Lin, an environmental engineer at Princeton University and coauthor of the new findings. These storm characteristics and sea level rise both influence how much damage hurricanes can wreak on coastal cities.

[Related: The average hurricane season is officially more intense]

During a hurricane, one cause of flooding is storm surge, which is caused by powerful winds pushing seawater to the shore. Drenching rains, like those seen during Hurricane Harvey in 2017, can also be devastating. “In the past, our group and others have been looking at these hazards more or less separately,” Lin says. For the new research, she and her team wanted to understand what happens when storm surge and rainfall join forces.

The researchers investigated how thousands of simulated storms would impact the Gulf and Atlantic coasts under late 20th century and projected future climate conditions. The team homed in on so-called joint extreme events, during which the amount of rainfall produced during a 24-hour period and the storm tide—the total seawater level from storm surge and normal tide—each had a 1 percent probability of occurring in any given year. 

“Such events actually are very rare in the historical period,” Lin says. Joint extreme events would be expected to occur about once every 200 to 500 years along the Gulf of Mexico, and less than once every thousand years on average along the New England coastline under historic climate conditions. However, Lin and her colleagues calculated that by 2100, these extreme floods might strike every 10 to 30 years along the Gulf Coast and southeast Atlantic, and every 3 to 10 years along New England and the Mid-Atlantic. 

“In the future climate it’s more likely that we’ll get extreme surge and extreme rainfall at the same time, so that you will have much higher total flooding,” she says.

The researchers also estimated that, in most areas, the increasing intensity and sluggish speed of future hurricanes will play a more important role in these extreme floods than sea level rise.

The findings do come with several caveats. There’s still uncertainty about how much hurricane frequency and sea level rise will change in the coming decades, and the researchers focused on a climate scenario in which greenhouse gas emissions are not curbed. As a next step, Lin and her team will explore how their predictions might change under less dire emissions scenarios.

The findings offer a “big-picture view” on how storm surge and rainfall will worsen flooding in the future, Wahl says, and offer a jumping-off point to identify vulnerable locations within each region. More localized, detailed modeling could help unpack how climate change is creating storm conditions that lead to more flood risk, he says.

There are a number of ways that coastal cities can prepare for the onslaught, including restoring natural buffers, such as wetlands and oyster beds, and constructing seawalls and other barriers. Floods driven by both extreme rainfall and storm surge may pose a particular challenge, Wahl says, because barriers that block incoming storm surge may also prevent rainwater from draining into the ocean.

“That’s where studies like this that tell us about the chances that storm surge and rainfall coincide in the future…can help us make better decisions when it comes to adapting for both inland flooding and coastal flooding,” he says.

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In Wisconsin, poaching that targets gray wolves may be exacerbated by wintry weather and hunting seasons for other animals, a new analysis suggests. 

Researchers examined three decades of wolf tracking data and found that poaching in the state increased during snowy periods when wolf tracks are easier to detect. When these conditions coincided with hunting seasons for deer and other large mammals, the rate of poaching increased more than six times. The findings emphasize the need for stronger protections for wolves, the study authors wrote on February 2 in Scientific Reports.

“The odds are that a wolf in Wisconsin is more likely to die of poaching than any other cause,” says Francisco J. Santiago-Ávila, the Big River connectivity science and conservation manager for Project Coyote, a nonprofit based in Larkspur, California, and a coauthor of the paper. Yet poaching is often underestimated when states develop the population estimates used to determine protections and hunting quotas. “It’s critical for state agencies to focus on these periods of time when these [hunting] activities increase, because we’re seeing that poaching increases during those times,” he says.

Gray wolves once ranged across much of North America. However, they were hunted nearly to extinction in the United States during the 19th and early 20th centuries before receiving protection under the Endangered Species Act in the 1970s. 

[Related: Wisconsin’s gray wolves are in serious trouble]

In October 2020, the Trump administration announced that it was removing gray wolves from the list of endangered species in the lower 48 states. This led to a surge in hunting in Wisconsin that Santiago-Ávila and his collaborators estimated dented the population by an alarming 27 to 33 percent. Six Native American tribes in northern Wisconsin and environmental groups filed lawsuits to block a second hunt that was planned to start in November. In October, a judge ordered a halt on the hunt while the state’s Department of Natural Resources comes up with a new wolf management plan, which is expected to be finalized by June.

Previous studies have indicated that poaching is the main cause of death for most wolf populations in the US, Santiago-Ávila says, and that illegal killing increases after protections are loosened. People poach wolves for a variety of reasons, including concern for livestock and general animosity towards the animal and other predators. Some deer and bear hunters also view wolves as competition, or a threat to their hounds. 

For the new research, the team investigated poaching during the years when gray wolves were still listed as endangered species. They used data from the Wisconsin Department of Natural Resources, which tracked 495 radio-collared wolves between 1979 and 2012.

To identify which times of year were most dangerous for wolves, the researchers analyzed how the rate of poaching changed in response to weather and human activities. These included the hunting seasons for other animals such as deer and bears, and periods when hunting hounds were trained. The team examined the number of reported poaching deaths, in which a carcass is recovered, as well as cases where wolves vanished when their transmitters stopped working—which is nearly always a result of poachers destroying the collar, says Adrian Treves, an ecologist at the University of Wisconsin-Madison and another coauthor of the new findings.

He and his colleagues found that the poaching slowed during the period from mid-April to the beginning of July, when the snow had melted and hunting and hounding weren’t allowed. “Adult wolves get a breather during that time,” Santiago-Ávila says. “They’re not as easy to detect and there’s no people around.”

By comparison, the rate of poaching more than doubled during late winter to early spring, when there was still snow on the ground but hunting and hounding had ceased. But when snow and hunting periods overlapped from late fall to early winter, the rate of poaching rose by more than 650 percent.

Wolf disappearances also increased by more than 50 percent during the snowy period after hunting ended, and by smaller amounts from July through early January. The researchers suspect that poachers are more willing to take the time to tamper with the collars of the wolves they’ve killed when there are fewer people about to notice and report them, Treves says.

The new findings indicate that, even when wolves are supposed to be protected, snow cover and hunting allow poaching to flourish. There are several possible explanations for why poaching seems to shoot up when these two factors coincide. 

More potential poachers might be roaming during this season, either because they’re legally hunting other prey or because they’re willing to use the commotion of the hunts as cover. 

However, “the chances of being caught increase when there are hundreds or even thousands of hunters in the field,” Treves says. This might cause poachers to change their behavior during hunting seasons, such as leaving the collars behind after killing a wolf in fear of getting caught if they stick around after the act. “There’s a lot of poaching that goes on that is detected because the collars aren’t damaged.”

Delisting wolves as an endangered species and instating wolf hunts in Wisconsin could indicate to the public that wolves aren’t valued and population numbers are not at risk, further emboldening poachers, Santiago-Ávila says.

Aside from restricting hunting, the state could provide additional protection by implementing patrols throughout the forests to deter poachers, Treves says. He and his colleagues have previously observed that poaching diminished when Wisconsin sent people out to monitor wolf populations in the late 1990s.

There’s already strong existing evidence that poaching and other human activities are a major cause of death for large predators, Andrés Ordiz, a conservation biologist at the University of León in Spain who wasn’t involved in the research, wrote in an email. “That is a well-known fact, but [this] study is important because it quantifies poaching in a specific study area and taking into account different factors, such as seasonality, and including a large dataset,” said Ordiz, who studies interactions between brown bears and wolves in Scandinavia. “It seems to me that the results should be taken into account by conservation and management agencies in that area, and the study is interesting elsewhere as well.”

The new study highlights the importance of considering the impact of poaching when estimating wolf populations, Lisette Waits, a conservation biologist at the University of Idaho who has studied gray wolves in Idaho and red wolves in North Carolina, wrote in an email. 

“These results are very interesting and valuable for documenting the increased mortality and poaching risks for protected wolves associated with legal hunting seasons,” Waits said. “This study provides insight about the importance of developing policies and procedures such as increased law enforcement during active hunting seasons to minimize risk to endangered carnivores like wolves.”

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Last week, Pfizer reported that a trio of lab experiments suggest that its COVID-19 pill, Paxlovid, will hold up well against the Omicron variant. 

The antiviral was authorized in December for people at high risk of becoming seriously ill from COVID-19. Unfortunately, despite these promising developments, Paxlovid and other COVID-19 treatments are still in short supply across the country. Half of the 20 million Paxlovid treatment courses purchased by the US aren’t expected to be delivered until June, and the other half by September.

However, experts are optimistic that Paxlovid and other oral antivirals could become an integral weapon against the novel coronavirus.

“It’s really nice to have the antivirals as a complementary part of our treatment approach, and [this is] something that is coming out at just the right time,” says Elizabeth Duke, a physician-researcher at Fred Hutchinson Cancer Research Center in Seattle. “The science is there; it’s really the delivery piece that is lacking.”

Michael Ison, an infectious diseases physician at Northwestern Medicine and the Northwestern University Feinberg School of Medicine in Chicago, hopes to see Paxlovid become more accessible as production ramps up. 

“At some point we would love this drug to be something like Tamiflu, where you can go to any pharmacy to receive it and your doctor can prescribe it more easily,” he says. “Now it’s still very limited.”

Encouraging evidence against new COVID variants

Prior to the emergence of Omicron, healthcare providers have relied on monoclonal antibodies to prevent newly diagnosed COVID-19 patients from developing severe symptoms. These lab-made proteins mimic the antibodies the body naturally makes to fight off the virus.

“Antibodies coat the virus…they latch onto the virus whenever they can find a nice landing spot,” Duke says. “It prevents the virus from entering the human cell, and it also helps the human immune system find the virus and clear it out using its own immune mechanisms.”

Antivirals like Paxlovid, Merck and Ridgeback Biotherapeutics’s molnupiravir, and remdesivir instead prevent the virus from making copies of itself. Paxlovid does this by interfering with one of the virus’s enzymes called a protease. In order to replicate, the virus must make long strings of proteins that the enzyme cuts into individual pieces. Paxlovid prevents this process from happening, which leads to “completely dysfunctional” viruses, Duke says. 

In clinical trials, Paxlovid, molnupiravir, and remdesivir reduced the risk of hospitalization and death in high-risk COVID-19 patients by nearly 90 percent, 30 percent, and 87 percent, respectively. 

On January 18, Pfizer reported the results of the three laboratory experiments, which haven’t yet undergone peer-review. In the first experiment, researchers found that the drug’s key ingredient, nirmatrelvir, was equally successful at blocking protease from Omicron and the original virus strain. In the other two experiments, researchers tested nirmatrelvir in cells infected with several different variants, and found the drug performed similarly well against Omicron and other versions of the virus. 

These preliminary results are encouraging but not particularly surprising, Ison says, given the antiviral doesn’t target the spike-shaped protein on the surface of the virus like monoclonal antibodies do. This can give antiviral pills an upper hand over antibody treatments, since the Omicron variant has a large number of mutations that make the spike proteins less recognizable. “I wouldn’t have expected any change in efficacy, but it definitely gives us primary data to show that it is effective in the test tube for Omicron,” Ison says.

Duke describes the new findings as reassuring. “It’s great to see the actual data,” she says. “Based on the mechanism of the antivirals I would expect it to work against Omicron and also future variants.”

By contrast, many of the more widely used antibody treatments, which do target the spike protein, are markedly less effective against Omicron than previous variants. The Food and Drug Administration recently restricted the use of two antibody therapies by Regeneron and Eli Lilly. “The antivirals target parts of the viral machinery that are so much more core to what the virus does,” Duke says. “It would be surprising if there were a lot of mutations in that part of the virus.”

The difference between these two strategies was underscored in a brief report published on January 26 in the New England Journal of Medicine. Researchers found that molnupiravir, remdesivir, and an antiviral Pfizer developed that’s similar to Paxlovid but given intravenously all retained their effectiveness at vanquishing Omicron in cell cultures. On the other hand, the antibody treatments the team tested were less effective against Omicron than previous variants. In one of its three experiments, Pfizer and collaborators at the Icahn School of Medicine at Mount Sinai in New York tested the antivirals molnupiravir and remdesivir in addition to nirmatrelvir, and found that they too were able to control Omicron.

Next steps for COVID-19 pills

Unfortunately, Ison says, very few pharmacies carry Paxlovid at this point, and those that do only have a small amount available. “So not a lot of patients have gotten the medication, and we don’t yet have real-world experience looking at patients that have received this therapy and how effective it is in getting people to feel better quicker with Omicron,” he says.

In an announcement of the results from the three Paxlovid experiments, Mikael Dolsten, who leads Pfizer’s Worldwide Research, Development and Medical organization, said that the company will “continue to monitor the treatment’s activity in real-world settings” to validate the findings.

Pfizer is also investigating whether Paxlovid can prevent people who have been exposed to the virus by a member of their household from developing COVID-19. Duke and her colleagues are studying this question as well for molnupiravir. She says that gathering more data on how well both treatments work in vaccinated people will be important as well, since clinical trials for the drugs focused on unvaccinated participants.

A crucial advantage of both of these antivirals is that they’re given as pills, as opposed to an injection or infusion. This means they can be taken at home, making them much easier to administer than other COVID-19 treatments. However, there are also drawbacks. As with other treatments, the oral antivirals are most effective when given early in the course of the disease. Paxlovid also interacts with many other drugs, including cholesterol and blood pressure medications and antidepressants. Molnupiravir, meanwhile, is not recommended for pregnant people. 

Duke hopes that as supplies of these drugs become more plentiful, providers will be able to choose among various treatment options to decide what will work best for each patient. As she puts it: “I’m really excited about the potential for the oral antivirals to be just as effective as the antibodies, if not more so.”

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Bats are masters at detecting sound—and a lot of it has to do with the mechanics and structure of those adorably large ears. A set of unique inner ear features may explain how one group of bats evolved the sophisticated echolocation strategies that have allowed them to thrive on every continent except Antarctica, scientists report today in Nature.

The researchers examined the skulls of 39 bat species from two major groups called Yinpterochiroptera and Yangochiroptera. They discovered that the yangochiropterans, which includes most bat families and 82 percent of echolocating species, have inner ears unlike those of any other mammal. These bats have inner ears with extra space inside the cochlea and more neurons, which may help them hunt within a broad range of environments. 

“We posit that it enables the really complicated echolocation calls that the yangochiropteran bats are famous for,” says Bruce Patterson, a curator of mammals at the Field Museum of Natural History in Chicago and coauthor of the findings.

Bats were traditionally divided into two groups called Megachiroptera and Microchiroptera, or megabats and microbats. Megachiroptera included the flying foxes, which generally find fruit and nectar by sight and smell, although a few also use tongue clicks as echolocation signals. Microchiroptera encompass the bats that have a type of echolocation that uses sounds produced in the larynx, known as  laryngeal echolocation. Microbats mostly eat insects, including agricultural pests, and other small animals. 

However, since 2000, genetic evidence has indicated that some of these echolocaters are actually more closely related to megabats than to other microbats. This led researchers to propose two new groups. Yinpterochiropterans dwell in the Eastern Hemisphere and include flying foxes as well as a few other families such as the horseshoe and mouse-tailed bats. By contrast, the 938 yangochiropteran species are found around the world. Their ranks include the free-tailed bats, vampire bats, ghost-faced bats, the big brown bat, and the ever-popular charismatic Honduran white bat.

[Related: How humans can echolocate like bats]

The wide array of adaptations found among these bats have stymied scientists searching for anatomical traits that could differentiate yangochiropterans from yinpterochiropterans. “Most of the diversity is in the yangochiropterans,” Patterson says. “So finding something that tied them all together was like a needle in a haystack, but this inner ear character suite seems to be exactly that.”

He and his collaborators investigated skulls from 19 of the 21 families of living bats. The team used CT scanning to peer inside the tiny skulls and examined fine cross sections of the inner ear structures under the microscope. 

Since the Jurassic Period, mammals have had a distinctive arrangement of inner ear structures within the snail shell-shaped cochlea. A cluster of neuron cell bodies called a ganglion transmits nerve impulses received by hair cells to the brain. The ganglion is contained in a thick bony wall perforated by tiny pores that allow nerve fibers to pass through.

But in yangochiropterans, the setup looks a bit different. “As you ascend this spiral, the wall opens up,” Patterson says. In some bats, the tiny pores become “much bigger windows” that allow large nerve bundles to pass through. Eventually, Patterson says, “the wall just disappears and the ganglion actually flops out of the canal.” In other yangochiropterans, the bony wall is absent throughout the length of the ganglion canal. As a result, the bats can pack in more neurons to receive incoming auditory signals.

What this suggests, Patterson says, is that “it was the greater freedom from constraints of the bony canal, the larger size of the ganglion, and the more intimate bundling of [nerve fibers] that was responsible for the explosive diversification of the yangochiropteran bats.”

Among yinpterochiropterans, the species that echolocate emit a barrage of sound pulses at a constant frequency. This kind of echolocation is great for finding insects scampering over leaves and other clutter but isn’t much help for open-air hunting, Patterson says. Yangochiropteran bats utter echolocation calls at longer intervals that start off high before swooping down to lower frequencies. These cries effectively give the flying mammals a more powerful “flashlight beam” that can travel farther and can gather more diverse information about their surroundings. 

The strategy could be adapted for a broader range of conditions. It “represented kind of an adaptive breakthrough for bats because it gave them mastery of the night skies and freed them from focusing on bushes,” Patterson says.

[Related: Bat echolocation could help us understand ADHD]

The findings indicate that the walled canals characteristic of yinpterochiropteran bats transitioned over time to create the unique inner ear architecture of yangochiropterans, M. Brock Fenton, a biologist at Western University in London, Ontario, wrote in a short review published in the same issue of Nature. This supports the idea that echolocation emerged before this split, and the skill was later lost in some yinpterochiropterans.

“This is an exciting new mammalian character identified in bats that can be used to shed new light on how laryngeal echolocation has evolved in mammals, addressing a long-standing evolutionary debate,” Emma Teeling, a professor and bat biologist at University College Dublin who wasn’t involved in the research, wrote in an email.

Intriguingly, the researchers identified two yangochiropteran bats that, unlike their close relatives, had a thick bony wall running the entire length of the cochlea. It’s not clear why this evolutionary reversal took place, although Patterson suspects it’s related to the bats’ highly specialized hunting strategy, which involves skimming the water’s surface and grabbing small fish or insects with their feet.

This observation highlights the fact that many questions about how echolocation has evolved in both bat groups remain to be investigated, he says. 

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This month California became the first state to require insurance plans to cover at-home tests for sexually transmitted infections.  

Officials hope the move will make STI testing more affordable and accessible. Sexually transmitted infections such as syphilis, gonorrhea, and chlamydia have been on the rise for years across the United States, and the pandemic has only worsened the situation. 

“We’re hoping that these test kits done at home will assist [those] individuals that just don’t feel comfortable going into a clinic,” Leticia Berber, a Fresno County Department of Public Health health educator, told ABC30 (KFSN-TV).

Last spring, the Centers for Disease Control and Prevention announced that reported annual cases of STIs in the US had reached an all-time high for the sixth consecutive year in 2019. The agency has cited a number of reasons for the trend, including difficulty accessing STI prevention and care, decreased condom use among vulnerable groups, including young people and gay and bisexual men, and cuts to STI programs at the state and local level.

[Related: America’s sexually transmitted disease rates are out of control]

The fact that these infections can be asymptomatic may also be playing a role, says Sarah Horvath, an OB-GYN at Penn State Health Obstetrics and Gynecology. “A lot of patients may not know that they have chlamydia, gonorrhea, or syphilis; all three of them can be silent,” she says. “So they may not seek care.” An additional factor may be that people who have been previously treated can also be reinfected by their partners, she says.

The arrival of COVID-19 has compounded this problem. “I’m very, very concerned that we are going to see even bigger increases for 2020 and 2021,” Horvath says. Since the pandemic began, people have become more hesitant to seek out screening or attend routine checkups. Some are spending more time with abusive partners who may limit their access to healthcare, says Horvath. On top of this, healthcare systems in many areas have been overwhelmed, ​​limiting their ability to readily treat and diagnose STIs.

“In some places even if a patient really wanted to get in, they’re seeing longer wait times,” Horvath says. “Especially if they’re a new patient, live in a rural area, or part of a group that was already somewhat marginalized within the healthcare system, it’s even harder to access care.”

Requiring insurance companies to cover at-home tests for HIV, chlamydia, and other infections is one of several measures included in California’s new law to combat rising STI rates. “This is the first law of its kind, and I’d say it’s kind of cutting-edge,” Stephanie Arnold Pang, senior director of policy and government relations for the National Coalition of STD Directors, told Kaiser Health News (KHN). “We want to bring down every single barrier for someone to get STI testing, and out-of-pocket cost is a huge factor.”

The rule went into effect on January 1 for people with state-regulated private insurance plans, although how much they pay out-of-pocket will depend on their plan, provider, and eligibility for free screening. Meanwhile, the state’s Medicaid program is still updating its billing codes to pay for the tests. Another potential complication is that some labs may hesitate to analyze the samples people send in because the tests haven’t been approved by the US Food and Drug Administration for use at home, KHN noted, which means they have not yet been extensively tested by federal agents, like at-home COVID-19 tests. 

“I think anything that improves the ability of a patient to access this care is fantastic,” Horvath says. “The question is whether or not they’re going to be able to then access the treatment they need if they get a positive.”

Still, she says, at-home tests have a number of advantages. “It has a level of privacy that some patients may find very appealing,” Horvath says. “This is a really nice alternative for those patients who can access this care without having to have a clinic visit.” 

In the future, she hopes to see similar bills passed in other states that cover at-home testing for people with state-sponsored insurance, as well as those with private insurance or no insurance. A top priority, Horvath says, is “making sure that everyone has access to the tests and making sure that there’s a mechanism for getting timely treatment of both patients and their partners if and when a test is positive.”

Equally vital to slowing the spread of STIs, Horvath adds, is making sure that people have access to resources about these infections and how to protect themselves.

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When fin whales capture their food, they end up scooping a lot of water into their mouths. Scientists in Canada have discovered a small, fatty structure in these marine mammals that may explain how they are able to engulf such vast amounts of prey-filled water without choking. 

When the researchers examined deceased whales, they identified a section of the soft palate that could shift to seal the upper airway while the whale feeds. The researchers, who dubbed the structure the ‘oral plug’ in the journal Current Biology on January 20, suspect that the plug also exists in other large baleen whales.

Fin whales are found in oceans worldwide and can grow to 85 feet long. They belong to a group of large baleen whales called the rorqual family, along with several other sea giants including the blue whale and humpback whale. Rorquals use a highly unusual strategy known as lunge feeding to capture krill, fish, and squid. During lunge feeding, the whale opens its mouth while shooting towards its prey at speeds of up to about 10 feet per second, allowing it to gulp a volume of water as large as its own body. Finally, the whale closes its mouth, pushing water out through its baleen plates, and swallows the remaining prey.

How the whales protect their airways as water floods the mouth has been a mystery, however. 

“We have a lot of knowledge about that whole process of the mechanics of lunging and engulfing all that food, and that’s pretty much where the knowledge stops,” says Kelsey Gil, a marine biologist at the University of British Columbia in Vancouver and coauthor of the findings. “We don’t know what’s going on in the throat.”

To find out, she and her colleagues examined the bodies of 19 fin whales.

“When we had the mouth open in this fin whale, we saw there was this massive chunk of tissue at the back of the mouth completely plugging the pathway that the food has to take to get to the esophagus and the stomach,” Gil says.

The almost 8 inch-wide bulbous structure was composed of fat and muscle. The researchers determined that it was part of the soft palate—the little sheet of muscle along the roof of the mouth from which the uvula hangs in humans. 

The oral plug was tightly wedged in place and could not be easily pushed free. When the researchers examined the muscle fibers of the soft palate, they concluded that the only way the oral plug could move for food to pass through during swallowing would be to shift backwards and upwards, and in doing so block the entry to the nasal cavities. 

“For these whales it’s a way to save energy,” Gil says. “It’s in its relaxed position and it’s going to be in that position most of the time and it only needs to be moved for a brief amount of time to push food through.”

The process is similar to what happens when humans swallow: The uvula is pushed back and throat muscles contract so food doesn’t go up the nose. 

“Once the nasal cavities and the upper airways are protected, you have this question of how the lower airways would be protected, [such as] the lungs,” Gil says. She and her collaborators manipulated the cartilage of the larynx, or voicebox, to see how it might move during swallowing. They found that the cartilage at the top of the larynx can come together to create a seal that prevents food or water from accidentally getting into the respiratory tract.

Additionally, Gil says, a muscular sac at the bottom of the larynx known as the laryngeal sac can create another protective barrier to block off the entry to the lungs. When the whales dive down to feed at greater depths, the pressure would push the sac upwards to plug the larynx. 

Being able to engulf massive amounts of prey is one reason that rorquals have managed to grow to such epic sizes. “The oral plug is really important for lunge feeding, and thus for allowing them to get as large as they have,” Gil says.

However, not everyone is convinced by the structure. Joy Reidenberg, a comparative anatomist at the Icahn School of Medicine at Mount Sinai in New York who was not involved with the research, says she has “serious reservations” about some of the evidence presented in the study. Based on what she has observed in dissections of rorquals, Reidenberg says, the rigid and floppy cartilage flaps at the top of the larynx wouldn’t fit together to make a particularly good seal in whales. 

Additionally, the motions of the larynx and mouth that make the protective seal and swallow food cannot both happen at the same time, she says. This is because both actions depend on moving the U-shaped hyoid bone, but in opposite directions.

Reidenberg also isn’t sold on the oral plug, which she doubts could move out of the way enough to allow food to pass by during swallowing. As is commonly observed in other animals, Reidenberg explains that it makes more sense for air to flow over the larynx and soft palate while food flows around the sides, like water parting around the bow of a boat. This would allow the whales to breathe and eat at the same time, she explains. It’s possible that the fatty bulge the team observed in the fin whale carcasses was actually caused by the weight of the larynx pushing down because the tongue was no longer there to hold it in place, Reidenberg says, although researchers would have to peek into a live whale’s mouth to find out for sure.

“I’m not convinced entirely that there is an oral plug, but if there is, I find that to be very interesting,” she says. “I’d love to see more evidence of that.”

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Since mid-December, the highly contagious Omicron variant of the novel coronavirus has dominated the latest surge in COVID-19 cases across the US. However, growing evidence is painting a picture of a variant that is less virulent than earlier versions of the virus, particularly among vaccinated people. Although Omicron is often described as mild, this variant still poses a very real danger, particularly for people whose age or medical conditions put them at higher risk of becoming very sick with COVID-19. 

An unpublished study of nearly 70,000 Southern Californians posted on January 11 to medRxiv found that people who caught Omicron were hospitalized at lower rates, had shorter hospital stays, and were less likely to be admitted to the ICU or die than Delta patients. Even among unvaccinated people, those with Omicron infections were less likely to be hospitalized than those who caught the Delta variant. 

The findings haven’t yet been peer reviewed, but are consistent with data from other countries, including a January 14 report from South Africa’s National Institute of Communicable Diseases. Researchers determined that prior infection and vaccination deserved much of the credit for protecting Omicron patients, but even unvaccinated people were less likely to become dangerously sick with Omicron compared to previous variants. Meanwhile, experiments in animals and cell cultures suggest that the strain might pack less of a punch because it primarily infects the upper airways rather than the lungs.

These studies all offer encouraging news. But this doesn’t mean that vaccinated, generally healthy individuals should write Omicron off as nothing to worry about, experts say.   

“We need to be cautious in not celebrating this,” says Sam Torbati, the co-chair and medical director of emergency medicine at Cedars-Sinai Medical Center in Los Angeles. Health officials and the public should be “aware that this disease is still a major problem and it’s going to continue to have a significant impact for populations that are at high risk.”

Since the beginning of the pandemic, hospital records have shown that the dangers of COVID-19 aren’t equally felt across the US population. Among the conditions that make individuals more vulnerable to serious illness from COVID-19 are cancer, diabetes, chronic lung disease, and heart issues. Those who are immunocompromised or pregnant are also at higher risk. Additionally, people with lower incomes and many racial and ethnic minority groups have faced a disproportionate burden from the disease.

Many of the conditions that put people at higher risk for severe COVID-19 are by no means rare. For example, more than 34 million Americans have diabetes, 16 million have chronic obstructive pulmonary disease (COPD), and about 18.2 million adults aged 20 and older have coronary artery disease. 

[Related: Omicron is causing record hospitalizations among the young and elderly]

“Perhaps in young, healthy patients [Omicron] won’t cause the same type of mortality that we saw with previous variants,” says Torbati. “But it’s still a big player when it comes to patients who have risk factors for advanced disease: people who have underlying medical conditions, especially older patients, and people who are not vaccinated.”

About 13 percent of US adults still haven’t received COVID-19 vaccines. “Just based on the number of unvaccinated people out there, or older people with significant comorbidities, it’s not that reassuring,” says Brian Stein, a pulmonary and critical care physician and chief quality officer for Rush University Medical Center in Chicago. “You might have a better outcome, but you still can get very sick from this.”  

The emerging data on hospitalizations and preliminary lab experiments on Omicron has led to the message that this variant is more “mild” than its predecessors. 

“It’s not that Omicron is mild as such; it’s milder than previous variants, and it’s particularly milder in vaccinated people,” says Edward Jones-Lopez, an infectious disease specialist at Keck Medicine of USC. 

Thinking of Omicron as mild can create a false sense of security. There are even some reports of people wanting to get infected to “get it over with.” But even healthy, vaccinated individuals can be in for a rough few days if they catch Omicron—and more research is needed to determine how likely the variant is to trigger long COVID. 

“You can look at population health data to say, ‘It’s mild on average, I probably won’t need to go to the hospital,’” Stein says. “You might not get sick, but you don’t know that for certain; the chance is not zero.”

In a Q&A live streamed last week, Mike Ryan, the director of the World Health Organization’s health emergencies program, noted that hundreds of thousands of people around the world have been hospitalized with the Omicron variant. “We can definitely say that an Omicron variant causes, on average, a less severe disease in any human being—but that’s on average,” he said.

And then there’s the high transmissibility. “You have plenty of people out there who are healthy, fully vaccinated, and boosted who actually develop mild symptoms, but they can still infect other people who might not be so lucky,” Stein says. 

“When we’re seeing large-scale transmission like this in communities, when hospitals are filling up and emergency rooms and ICUs may be overwhelmed, you need to take it seriously even if the expectation is that you might have mild disease,” he adds. 

[Related: What does it mean for Omicron to peak?]

Skyrocketing COVID-19 cases are putting many immunocompromised people in an especially dangerous position right now, as well as causing staffing shortages in hospitals, businesses, and schools and straining healthcare systems. “At some point you overwhelm your emergency rooms and hospitals. If you should need other care, it may not be available to you,” Stein says. “That always should be a concern when you have widespread transmission in the community, even of a milder variant.”

And just because Omicron seems to be less deadly than previous strains does not mean that this pattern will continue in the future. “The jury is still out on what’s going to happen with the next variants—and there are going to be more variants,” Jones-Lopez says. “This is what these bugs do, they are constantly mutating to avoid human interventions.”

We don’t know yet what the next variant of SARS-CoV-2 will bring, Torbati says, making it important to plan for all possibilities. “I think we need to be cautious and ask ourselves, ‘What is the worst-case scenario?’” he says. “How are we going to make sure that we minimize the impact of a virus that potentially is just as infectious as Omicron, but potentially far more virulent?” 

Going forward, updated COVID-19 vaccines may also target Omicron or other variants. But in the meantime, the currently available shots still offer powerful protection against becoming seriously ill with Omicron, even if they’re somewhat less effective at warding off breakthrough infections that we’ve been seeing with this variant. “Getting vaccinated and getting boosted are your best defenses from a medical standpoint,” Stein says. Widespread vaccination is crucial for limiting the emergence of new variants as well.

Additionally, Torbati points out, “vaccination doesn’t just help the younger individual; it helps them protect their loved ones who are older or have risk factors for [severe] disease.”

In addition to vaccines and treatments such as monoclonal antibodies, the preventative measures that people have been relying on throughout the pandemic remain crucial. Last week, the CDC reinforced the use of well-fitted masks in an updated guide to protective face coverings, particularly emphasizing the effectiveness of N95s and K95s in light of surging cases. “The same tenets around masking, avoiding large gatherings, and social distancing all still hold true with respect to slowing down the spread,” Stein says. “I don’t think the message really has changed with respect to what we need to do.”

The Omicron wave may have started to peak in states where the new variant struck earliest, and seems to be subsiding in South Africa, where the strain was first reported in November. It’s possible this may represent a turning point in the pandemic, says Jones-Lopez, although he cautions, “we still have to hang in there a few more months and see what this is going to do.”

For now, Omicron still represents a public health crisis across the US. For people whose age or other health conditions put them at risk for severe COVID-19, now is a time to be especially cautious, Torbati says. But that doesn’t mean that everyone else should relax their guard.

“Everybody is responsible for managing and doing their part with this pandemic, and nobody can say, ‘Oh, it’s not going to affect me, it’s not my problem,’” Torbati notes. “It’s the entire world’s problem…and the entire population needs to step up.”

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A new analysis has pushed the age of the oldest known Homo sapiens fossils from eastern Africa back to more than 230,000 years. 

The remains, known as Omo I, were discovered in sediments sandwiched between layers of volcanic ash in Ethiopia in the late 1960s. Previous estimates dated the fossils to around 197,000 years old. However, a detailed examination of ash from the site and from distant volcanoes indicates that Omo I is even more ancient, an interdisciplinary group of scientists reported in Nature today.

“This work is important in demonstrating that the Omo I skeleton is pretty certainly more than 230,00 years old,” Chris Stringer, a paleoanthropologist at the Natural History Museum in London who has also studied the remains, said in an email. 

The mysterious Omo I consists of pieces from a single skull that reveal a tall cranium and chin—features distinctive enough to identify it as a member of Homo sapiens on discovery, says Céline Vidal, a volcanologist at the University of Cambridge and coauthor of the most recent findings. The remains were found in the Kibish Formation of the lower Omo valley in southern Ethiopia, an area that was very volcanically active at the time when it was inhabited by early human ancestors. 

Nonetheless, the rift valley would have been an appealing place to live during this era, as it was filled with lakes and woodlands. The volcanoes would have created fertile soil and plenty of obsidian rock to craft into tools. The valley “provided resources for the species to thrive,” Vidal says. 

It’s difficult to determine the age of poorly preserved bones directly, Vidal says. Instead, researchers have investigated Omo I’s surrounding environment. Earlier efforts have focused on a layer of volcanic ash near but not above or below the fossils, which yielded an age just under 200,000 years old. “But the big uncertainty is the position of this ash layer relative to the fossils,” Vidal says. 

More tantalizing is a six-foot-thick layer of ash not far above the sediments that encased Omo I. This deposit is clearly somewhat younger than the fossils that lie beneath it, but pinning down its age has proven challenging. The material has a consistency like flour, making it too fine for scientists to analyze using a technique called radiometric dating.

However, they could determine the composition of the ash. “Every volcanic deposit has its own fingerprint, its own chemical signature,” Vidal says. If researchers could identify the volcano responsible for the fallout, they might be able to find chunkier rocks from the same eruption elsewhere that could be more easily aged.

Vidal and her collaborators tackled this question by investigating major volcanic eruptions that took place in Ethiopia from 300,000 to 60,000 years ago. “The broader significance of this project was to figure whether those big eruptions had an impact on the evolution and migration patterns of the Homo sapiens back then,” she says. 

[Related: Is it time to change the way we talk about human evolution?]

To gauge the size of the eruptions, Vidal and her team sampled ash from various sites around the country, including the Kibish Formation. They found that the chemical fingerprints of the ash layer above Omo I matched that from an explosive outburst of the Shala volcano about 217 miles to the northeast. 

By analyzing fist-sized pumice rocks in the volcano’s vicinity with radiometric dating, the researchers calculated that the eruption took place around 233,000 years ago. This indicates that the ash layer above Omo I is also 233,000 years old, so the ancestral fossils must be even older. Given how massive the eruption was, Vidal says, it’s not surprising that fresh, fine ash was carried hundreds of miles away.

Based on genetic data, scientists have estimated that Homo sapiens diverged from other early hominins between 350,000 and 200,000 years ago. Having a minimum age of 233,000 years for Omo I “makes sense with this model,” Vidal says. Another set of fossils from Morocco has been dated to 315,000 years old, although Vidal says they do not possess certain features found in Omo I and later humans, including the tall cranium and chin.

The next step, she notes, will be to determine a maximum age for the fossils by repeating the analysis with samples of fine ash from layers beneath them. The researchers also hope to fine-tune estimates for the age of the second-oldest modern human remains in the region, known as the Herto fossils, which come from northern Ethiopia and are estimated to be roughly 160,000 years old. 

“There’s a big gap in between the eruptive history and the archeological history which we’re very slowly filling in,” Vidal says.

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Researchers have identified two new species of shark in the waters off eastern Africa. The rare little creatures range from about three to four-and-a-half feet in length and belong to a group called sixgill sawsharks. Their discovery came as a surprise to scientists, who previously knew of only a single species of sixgill sawshark.

“The present study…[reinforces] both how important the western Indian Ocean is in terms of shark and ray biodiversity, but also how much we still have left to find,” Simon Weigmann, a marine biologist at the Elasmobranch Research Laboratory in Hamburg, told Popular Science in an email. He and his colleagues reported their findings on the new sharks on March 18 in the journal PLoS ONE.

Sawsharks are known for their long, flat snouts studded with teeth, which they use to slash their prey to ribbons. The sea animals have similar chainsaw-like mouths to another ocean fish, known as the sawfish, though they aren’t at all related. Sawfish are actually rays and can grow up to 23 feet long.

Most sawsharks have five gill slits on each side of their bodies, as is typical for sharks. Until now, the only sawshark species thought to have six gill slits—known as Pliotrema warreni—was found in the waters around South Africa and southern Mozambique.

This unusual feature doesn’t seem to play a vital role in the sharks’ survival. “The presence of six (or seven) gill slits per side is considered a characteristic of very primitive sharks,” Weigmann said. “There is no advantage known for them in having six gill slits.”

The first hint that P. warreni wasn’t the only six-gilled sawshark in the sea came in 2017, when a fisherman in the village of Andavadoaka in southwest Madagascar contacted Weigmann’s colleague Ruth Leeney, who is based at the Natural History Museum in London. At the time, she was studying sawfish in Madagascar. The fisherman told her that he’d just caught two of the rays. But the animals turned out to belong to an entirely new species of six-gilled sawshark rather than a new variety of ray. Weigmann and his team were able to identify several more members of this previously overlooked species in museum collections.

Then in 2017 and 2019, a few more of Weigmann’s colleagues mailed him two sawsharks that fishermen had captured as by-catch off the coast of Zanzibar. After a thorough examination, the researchers declared the specimens to be a third species of sixgill sawshark.

The newly recognized sharks were named Kaja’s sixgill sawshark and Anna’s sixgill sawshark in honor of Weigmann’s daughter and niece. Their snouts are shaped slightly differently from that of their cousin P. warreni. All three sharks have whisker-like organs called barbels that they use to detect food; they’re also found on catfish. However, the newly discovered sharks’ whiskers are placed farther from the mouth. It appears that none of the sixgill sawshark species have overlapping ranges.

“The identification and formal description of the two new species is extremely important for evaluating their rarity and population status, as well as for assessing their vulnerability to fishing operations,” Weigmann said. He is particularly concerned about Anna’s sixgill sawshark, which has, as of yet, only been seen in shallow waters, a location where it might easily end up in a fisherman’s catch by accident.

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Volcanic hotspots such as Ascension Island in the South Atlantic may have a surprising origin, indicates a report published on January 6 in Science.

Scientists have long thought that these islands were fueled by thermal plumes welling up from deep within the Earth’s mantle. However, when researchers compared the temperatures of volcanic hotspots and mid-ocean ridges around the world, they found that many of these so-called hotspots were actually rather cool. 

Conditions at these sites might not be warm enough for the plumes to travel up from the deep mantle, says Carolina Lithgow-Bertelloni, a geophysicist at the University of California, Los Angeles and coauthor of the findings. Understanding how these enigmatic hotspots do form may provide important clues about geologic processes at work at shallower depths beneath Earth’s surface, she and her team concluded. 

Most of the world’s volcanic activity occurs at the boundaries between tectonic plates, where underwater mountain ranges called mid-ocean ridges are found. “At these mid-ocean ridges the material that’s underneath the crust on which we live upwells and melts and forms volcanism, and as a result the plates separate and you create new ocean floor,” says Lithgow-Bertelloni. “It’s an expression of the large-scale motions inside the [planet’s] interior.”

[Related: Volcanic eruptions are incredibly hard to predict. Here’s why.]

However, in rare cases volcanoes are created by different processes and may pop up far from mid-ocean ridges. This second category includes the volcanic islands of Hawaii and the Galápagos. The most widely-accepted explanation is that superheated plumes rise from great depths, perhaps even from the boundary between the Earth’s rocky mantle and the core, at these hotspots. The plumes melt the surrounding rock to form magma, which eventually erupts from the surface. As the tectonic plate overlying the plume moves, a chain of volcanoes forms over time. 

Scientists have found that the basaltic rock formed when lava cools at these sites has different chemical properties from basalt formed along mid-ocean ridges. “​​If they do come from hot material being brought up [from] deep in the interior, they give us a window into the chemistry of the interior which we have no other way of accessing, and also into the chemical evolution of the planet,” Lithgow-Bertelloni says.

The temperature of mid-ocean ridges should represent typical temperatures within the mantle, she says. In order to upwell, a plume must be somewhere between 100 to 150 degrees Celsius (212 to 302 degrees Fahrenheit) hotter than the surrounding rock. “They have to be hotter to be able to rise through the entire mantle, and therefore hotter than the mid-ocean ridge,” Lithgow-Bertelloni says. 

Researchers have estimated that hotspot basalts melted at temperatures roughly 100 to 300 degrees Celsius (212 to 572 degrees Fahrenheit) higher than those at mid-ocean ridges. However, Lithgow-Bertelloni says, estimates for a given hotspot are often inconsistent and only reflect temperatures within the upper portion of the mantle, far above the depths at which plumes originate.

The key to determining temperatures as far as 600 kilometers (373 miles) beneath mid-ocean ridges and volcanic hotspots, she says, turned out to be earthquakes. Whenever an earthquake takes place, it releases huge amounts of energy in the form of seismic waves. The speed at which these waves travel and arrive at seismometers varies depending on the composition, depth, and temperature of the surrounding rock.

The researchers used a model that drew upon seismic measurements from around the globe to infer the temperature at all 46 known oceanic hotspots. The team also calculated that the average temperature at mid-ocean ridges was roughly 1,388 degrees Celsius (2,530 degrees Fahrenheit).

“What we found incredibly interesting and shocking was that most of the hotspots are really not that hot,” Lithgow-Bertelloni says.

She and her colleagues identified three distinct clusters of hotspots. When they zeroed in on 26 hotspots with well-documented plumes, the researchers determined that 12 were truly hot, with temperatures 155 degrees Celsius or more above that of mid-ocean ridges. However, 10 hotspots were merely warm, with temperatures 50 to 136 degrees Celsius (122 to 277 degrees Fahrenheit) hotter than mid-ocean ridges. An additional four were downright chilly, with temperatures similar to or cooler than mid-ocean ridges.

The toastiest cluster of hotspots included the volcanoes of Iceland, Samoa, Galápagos, and Hawaii. Warm hotspots were found at Bermuda and the Canary Islands, while cold hotspots were found at Cameroon, Ascension Island, and the Great Meteor, or New England, hotspot in the North Atlantic. 

“We still have hot hotspots, and those hot hotspots reflect material that is deep and from an ancient domain, but there aren’t very many of them,” Lithgow-Bertelloni says. “The rest are different, which means we’re in new territory.”

One explanation is that cold and warmish hotspots may originate at relatively shallow depths within the mantle. “We also suggested that maybe these [deep] plumes started hot and then they got trapped in material that is cold,” Lithgow-Bertelloni says. “It doesn’t stop them altogether; they still are able to rise, but they cool down and rise more slowly.”

One source of uncertainty for the temperature estimates the researchers developed is that earthquakes and the seismometers that record their activity aren’t evenly distributed around the world. “So our coverage of the earth’s interior is not complete,” Lithgow-Bertelloni acknowledges.

Still, she says, the findings indicate that volcanic islands that look similar on the surface may have very different origins. As a next step, the researchers will explore how volcanic sites differ between the Pacific, Atlantic, and Indian Oceans. 

“Those ridges are recording the ancient tectonic history…of the planet,” Lithgow-Bertelloni says. This history “could be revealed by the temperatures of the ridges, and the differences in temperature between the ridges and the hotspots in those ocean basins.”

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The western United States has endured a sharp increase in two kinds of pollutants related to wildfire smoke since the beginning of the century, a new analysis suggests. 

Scientists examined records of fine particulate matter and ozone from 2000 to 2020, and discovered that events in which people were simultaneously exposed to extreme concentrations of both pollutants have become more frequent, cover larger areas, and last longer. Furthermore, the researchers found a connection between days in which high levels of ozone and fine particulate matter co-occurred and areas burned by wildfires. They estimate that the maximum extent of land subjected to these noxious air conditions on a given day has more than doubled over the past two decades.

“We are expecting these trends to continue given climate change, so the best we can do at this point is to increase awareness and take steps to protect ourselves from worsening air pollution,” says Dmitri Kalashnikov, a doctoral student in environmental science at Washington State University Vancouver. He and his colleagues reported the findings on January 5 in Science Advances. 

Wildfires emit a mixture of hazardous compounds that contribute to cardiovascular and respiratory illnesses when people breathe them in, including fine particulate matter or “PM2.5.” These tiny particles suspended in the air are less than 2.5 micrometers in size—a small fraction of the width of a human hair. Wildfires also release some ozone, Kalashnikov says, as well as compounds that react with other pollutants to produce ozone. Studies indicate that ozone and fine particulate matter are disproportionately harmful when people are exposed to both pollutants at the same time, he adds.

In the past, levels of fine particulate matter across the western states tended to peak in winter. “You have these stagnant air patterns, and air gets trapped in the valleys and just sits there for days, which builds air pollution,” Kalashnikov says. “But wildfires have changed that equation.”

Climate change is worsening summer wildfire activity. Meanwhile, the hot, sunny conditions that persist during fire season also fuel the chemical reactions that increase ozone. “It used to be that ozone would be high in summer and PM2.5 would be high in winter,” Kalashnikov says. “It’s now changed to where both are high during the summer thanks to wildfire smoke.”

To investigate these trends, he and his colleagues examined daily air pollution records from a region that spanned from eastern Colorado to the west coast. The team divided the area into a grid with squares, or cells, measuring 1-degree latitude by 1-degree longitude. For every grid cell, the researchers identified the 37 days with the highest concentrations of ozone and of fine particulate matter annually. “Each year I looked at what are the top 10 percent days of PM2.5 and what are the top 10 percent days of ozone,” Kalashnikov says. “I was interested in seeing when and how often high levels of these two pollutants coincide.” 

Over the past two decades, the team found, periods when extreme levels of fine particulate matter and ozone co-occurred have significantly increased over much of the western U.S. between July and September. As a result, the researchers calculated, people’s exposure to poor air quality increased by about 25 million person-days per year (a measure that refers to the population of a given location multiplied by the number of days it faced extreme levels of ozone and fine particulate matter).

[Related: Colorado just saw its most destructive wildfire ever—in the middle of winter]

To understand the weather patterns that might drive this pollution, the researchers zeroed in on phenomena called atmospheric ridges or heat domes. During a heat dome—like the one that engulfed the Pacific northwest last summer—a block of hot air sits over an area for days on end. This leads to hot, dry conditions that allow wildfires to spark and spread, and allows air pollutants to build up. In the past four decades, Kalashnikov says, these weather patterns have become more common and persistent during the summer in the western states.

Finally, the researchers examined wildfire activity and air temperatures in the week leading up to occasions when ozone and fine particulate matter reached extreme concentrations. They identified a “robust correlation” between the extent of air pollution events and the amount of land that burned in the western United States and southwestern Canada in the preceding seven days, Kalashnikov says. Similarly, he says, widespread hot weather was correlated with widespread air pollution. 

“It’s this perfect storm of things which are all increasing to produce more air pollution and more population exposure to air pollution,” Kalashnikov says. “We can link these changes to increases in the kinds of weather patterns that cause this pollution…and also more severe wildfire years which produce more smoke.”

Questions for future studies include how these air pollution trends might continue to play out under climate change and how variables such as the type of land a wildfire sweeps over influence the kinds and amount of air pollution unleashed, Kalashnikov says.

One limitation of the findings is that the researchers had to rely on a network of stations to monitor air quality that is “relatively sparse” in some parts of the western United States, Kalashnikov and his team acknowledged in the paper. Increasing the number of monitoring stations is vital to get more accurate and detailed estimates, they wrote. 

Understanding the relationship between fine particulate matter and ozone levels “is tricky,” says Daniel Jaffe, an environmental chemist at the University of Washington who wasn’t involved in the research. He and his colleagues have previously found that the most extreme ozone and fine particulate matter concentrations tend to occur on different days. 

“Exactly why is it that we get these co-occurrences of [fine particulate matter] and ozone on some days but not others, and what is the interplay between wildfire smoke and urban air quality?” Jaffe says. Still, he says, the new paper “is definitely a step forward.”

The worsening air pollution described in the new report isn’t going away anytime soon, he adds, highlighting the importance of protecting indoor air quality and using prescribed burns and other techniques to manage forests so they’re less vulnerable to massive fires. “All of us in the West have to think about how we’re going to live with wildfires,” Jaffe says.

One crucial step is increasing people’s awareness of how pervasive and unhealthy air pollution from wildfire smoke can be, Kalashnikov says. “If there was more awareness, then it might lead to better policy solutions, maybe better protection for vulnerable communities [such as] outdoor workers and farm workers.” 

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PopSci is spending September relearning how to eat. As intuitive as our love of chowing down is, a lot stands between us and optimal eating. This month, we’ll break down diet myths, unlock delicious kitchen hacks, and explore our most common misconceptions about our grub.

Nearly a century ago, one of the first fad diets, known as the Hollywood or grapefruit diet, suggested that eating the tart fruit with every meal was the secret to staying thin. 

It wasn’t. But that didn’t stop diets from ballooning into a multi-billion dollar industry in the United States.

You wouldn’t know it from reading the promotional materials of all the apps, guidebooks, and influencers promising to help you shed pounds, but there’s a lot that researchers and physicians still don’t understand about weight loss. The one thing experts are fairly certain of is that dieting rarely works in the long run. Science suggests that there are many reasons for this, ranging from genetics to the kinds of foods available to us, as well as how the body reacts when we suddenly change how we eat.

“We’re oversimplifying the effect of ‘calories in and calories out’ without considering all the complexities of the physiology of the body’s natural desire to want to regain weight,” says Holly F. Lofton, director of the Medical Weight Management Program at NYU Langone. 

Here’s what we know about how fad diets set us up for failure—and why emphasizing goals other than weight loss may be the key to improving your health. 

Investigating diets

What exactly is a diet? 

At its most basic, the term refers to nutritional and lifestyle changes that a person makes to improve their health, Lofton says. Not all “diets” are bad or misguided; certain diets are essential for managing medical conditions, such as avoiding gluten if you have celiac disease. 

Often, though, when people use the word “diet,” they’re thinking of weight loss. Countless trendy plans have emerged in recent decades, from Atkins to Zone. Some are designed to restrict calories, while others limit fat or carbs, or cut out certain foods such as sugar and legumes. 

Whatever the approach, diets tend to follow a similar pattern: most people lose weight for several months, and then begin to gain back some or all of what they’ve lost, if not even more. Scientists aren’t fully certain why this is, says Kevin D. Hall, the section chief of integrative physiology at the National Institute of Diabetes and Digestive and Kidney Diseases. 

[Related: In 2021, as ever, the best diets are simple]

Part of the problem is that dieting is rather tricky to study. For the experiments that Hall and his colleagues run, participants stay at a clinic for several weeks and eat a tightly controlled meal plan. The goal is to explore how nutritional changes influence a person’s physiology. Earlier this year, the team reported that participants following a low-fat diet consumed fewer calories than those eating ketogenic (high-fat and low-carb), but had higher blood sugar and insulin levels, However, these studies are expensive, short, and don’t necessarily reflect how people behave outside the lab. 

More common are real-world studies in which people are randomly assigned to one diet or another and tracked over time. In one such clinical trial nicknamed DIETFITS, Stanford University researchers followed more than 600 adults for a year and found no significant difference in weight loss between those told to adopt a low-fat diet compared with a low-carb one. 

These kinds of studies also have drawbacks. It’s rare for the trials to last longer than a year or two, Hall says, and researchers have little way of knowing for sure how well people are sticking to their assigned diet. “We’re not lab rats, and so we go out and live our lives,” he says. “If I go to somebody’s birthday party, I might have a slice of birthday cake whether or not I’m on a low-carb diet.”

So it’s not easy to disentangle whether people regain weight because they aren’t following the diet as strictly as they did in the beginning, Hall says, or if there’s some other underlying physiological reason. Also puzzling is the small minority of participants in diet studies who actually do manage to lose weight and keep it off. 

“We don’t know whether or not [a diet] was effective for that person because of some sort of biological reason, or whether or not it was more about the social supports and being in the right place and time in their life to make a sustained change,” Hall says. Another conundrum, he says, is whether these people would have been equally successful if they’d been assigned to a different diet.

Weight is complicated

What is clear, however, is that dieting isn’t just a matter of willpower, says A. Janet Tomiyama, director of the UCLA Dieting, Stress, and Health Laboratory.

“Something society doesn’t quite grasp yet is that weight is really, really hard to control,” she says. “When somebody gains weight or their diet fails, they blame themselves rather than the thousands of forces that are conspiring to keep that weight on and to make you gain more weight.”

A big part of the explanation lies in genetics; some people’s bodies store fat more readily than others, says Lofton. But there are plenty of other variables, including their activity level, how much sleep a person is getting, and what medications they’re taking. 

There’s evidence, for example, that a poor night’s sleep disrupts levels of hunger-controlling hormones, leading to an increased appetite. And people who regularly work night shifts tend to gain more weight over time than daytime workers. “That can be really confusing for the body and people’s eating habits, if they’re working the overnight shift and sleeping poorly,” says Linda Antinoro, a registered dietician in the Nutrition and Wellness Service at Brigham and Women’s Hospital in Boston.

A person’s job is just one part of their food environment—the context in which people make decisions about what to eat. For many Americans, what’s most readily available are so-called ultra-processed foods. Researchers are still trying to figure out whether the additives and preservatives in these foods can affect our metabolisms, Lofton says.  

[Related: How to eat sustainably without sacrificing your favorite foods]

Hall and his colleagues are investigating the role that a person’s food environment plays in weight gain. In one experiment, participants who were offered ultra-processed foods such as Honey Nut Cheerios and margarine wound up eating about 500 calories per day more than people given whole foods such as apple slices and olive oil. This effect is particularly striking since the meals in each diet had the same amounts of fat, sugar, and other nutrients. 

However, Hall acknowledges, cutting out ultra-processed food isn’t exactly simple; not everybody has the time, money, or easy access to fresh produce. “One of the reasons why ultra-processed foods are so popular is because they’re so darn convenient,” he says. “They are typically engineered to be quite tasty, they have a long shelf life, they don’t require a lot of skill or equipment to prepare, and they don’t take very much time to prepare.”

Why your body resists weight loss

On top of all of this, dieting itself triggers changes in the body that fight against weight loss. When a person slashes their calorie intake, Tomiyama says, their body reacts as if it were enduring a famine. “Your body evolutionarily thinks, ‘Oh no, we’re in starvation mode…we have to get really efficient,’” she says. In other words: the dieter’s metabolism slows down, and they wind up burning fewer calories.

Hall and his colleagues have seen this firsthand with people who participated in the extreme weight-loss competition “The Biggest Loser.” While competing, the participants shed more than 120 pounds on average. Six years later, though, most had regained a fair amount of weight. Yet their resting metabolisms still remained sluggish. The people who’d kept the most weight off were those who’d increased their activity level by the greatest amount. In a surprising twist, though, they were also the participants whose metabolisms had slowed the most.

“It seems like in those folks, the lifestyle interventions that they had continued in order to keep the weight off were still being met by this continual resistance by the body,” Hall says.

[Related: What are calories?]

Dieting also causes a person’s appetite to increase. “You start to notice food more, and so it’s not just your body but also your brain that’s working toward getting you to eat more whenever you start depriving your body of calories,” Tomiyama says.

She and her team have also seen that dieting is just plain stressful. People who’d reduced their calorie intake had higher levels of the stress hormone cortisol than those who hadn’t. Being stressed only makes it harder to lose weight. “One of cortisol’s jobs is to signal your body to deposit energy as fat, especially in the belly region,” Tomiyama says. 

And fat-shaming just compounds the problem, she adds. “When you’re treated unfairly or experience discrimination because of your size, that’s ironically triggering these processes in your body that make you gain even more weight that’s going to put you at even more risk for fat-shaming and weight stigma,” she says. 

What you should do instead of dieting

Realistically speaking, Antinoro says, fad diets are rarely sustainable over the long haul. “We ask the question, ‘Is that doable for your lifestyle? Could you see yourself never having carbs for the rest of your foreseeable life?’” she says.

Still, it’s not surprising that diets remain entrenched in American culture. 

“Socially there’s pressure to lose weight, physicians are pushing you to lose weight, and so it makes sense why people would want to do something about it,” Tomiyama says. “Everybody’s screaming at them to.” 

Layered on top of this are the compliments dieters tend to receive as soon as they begin to lose weight. And with almost any fad diet, Hall says, there will be compelling success stories. For many people, though, dieting is ultimately a discouraging experience. 

“I do want people to get away from that term of ‘diet,’” Antinoro says. “It implies you’re on or off, you’re good or bad, it’s black or white.” Instead, she suggests, think about health-oriented steps you can take in your daily life—even if they never change your pant size. 

“It doesn’t always change the on-the-scale weight, but you’re seeing other markers that change in a healthy way,” Antinoro says. “Maybe it’s, ‘My blood pressure is better and I don’t need these three medicines,’ or, ‘I can play with my kids more and I’m not tired and am sleeping better.’”

Tomiyama recommends focusing your efforts on four key areas: stress management, getting good sleep, moving more, and adding more unprocessed foods such as fresh fruits and vegetables to your diet when possible. 

“You’ll notice I’m not talking about taking away the Snickers; I’m saying get more kale and strawberries,” Tomiyama says. “As soon as you start thinking of it as depriving yourself, that’s going to set off the stress processes.”

Start small, she advises. Pick an action you can do in the space of 10 minutes, whether that means going for a quick walk, eating an apple, stretching before bed, or reading a chapter of a book to destress. “Let’s just forget about the number on the scale,” Tomiyama says. “These are things that are going to help your health regardless of the number on the scale.”

One approach that’s gaining momentum is called Health at Every Size, which is aimed at building healthy eating and exercise habits and cultivating respect for people of all weights. More studies will be needed to assess the effectiveness of HAES for different groups. However, Tomiyama says, emerging research indicates that these interventions can be beneficial for health even if—or perhaps exactly because—the focus isn’t placed on weight loss.

Changing one’s relationship with food isn’t always easy, and some aspects of what and how we eat or move or sleep aren’t entirely within our control. The COVID-19 pandemic has only underscored this reality.

“All the indicators show that our diets have become worse during the pandemic, people are engaging in less physical activity, stress levels are through the roof,” Tomiyama says. “This is such a tough time for so many people, and it’s going to be all the more important to have compassion for yourself and not get into this blame-and-shame cycle that can result from dieting.”

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About 246 million years ago, a marine reptile roughly the length of a humpback whale patrolled the seas over present-day Nevada.

This ichthyosaur wasn’t just remarkable because of its massive size, according to scientists who recently analyzed a partial skeleton recovered from the Augusta Mountains. The new species notably lived just a few million years after the very first ichthyosaurs—which were roughly dog-sized—appeared in the fossil record. This means these swimmers supersized themselves much more quickly than whales did, according to research reported on December 24 in Science. 

“​​This fossil combined with the [other] fauna that we’re finding in Nevada is a true testament to how resilient life is, and how fast evolution can proceed if the environmental conditions are right and the opportunity is there,” says study coauthor Lars Schmitz, a paleontologist at the W.M. Keck Science Department of Claremont McKenna, Scripps, and Pitzer Colleges. “Even after a massive extinction event where the entire world is in turmoil, life can diversify really, really fast.”

Ichthyosaurs first arose 249 million years ago and hunted the world’s oceans for the next 150 million years before going extinct. Their streamlined bodies, flippers, and large eyes gave them a slightly dolphin-like appearance, Schmitz says. Indeed, ichthyosaurs shared a few similarities with cetaceans—whales, dolphins, and porpoises. Both groups evolved from land-dwelling animals that returned to the sea, developed similar body plans including powerful tails to propel themselves through the water, and in some cases grew to enormous sizes. 

The ichthyosaur fossil that Schmitz and his colleagues analyzed includes a skull more than 6 feet long, as well as parts of the right arm, spine, and shoulders. The new species, which they named Cymbospondyus youngorum, had a long snout filled with pointed teeth and a slender body.

Based on the size of its skull, the researchers estimated that C. youngorum would have reached roughly 58 feet long and weighed just under 50 tons. “This one is much larger than all the other ichthyosaurs that lived earlier and at the same time, so [it’s] essentially the first giant in the oceans,” Schmitz says. 

The remains of several other large ichthyosaurs around 33 feet in length have also been discovered near the C. youngorum specimen, he adds. Bulking up likely came with several advantages; in the oceans, larger animals tend to be efficient hunters, are protected from other predators, and can more easily regulate their body temperature.

The researchers compared C. youngorum to other ichthyosaurs of varying ages and anatomical traits, and identified two “pulses” of rapid growth early in the group’s evolutionary history. “It really helped us to understand that body size for ichthyosaurs evolved super fast,” Schmitz says.”

[Related: This ancient millipede was as big as a car]

He and his team then compared the ichthyosaur and whale family trees. They calculated that ichthyosaurs became giants within the first 3 million years of their 150-million-year history, while whales took 45 to 50 million years of their 56-million-year evolutionary history to reach approximately similar body sizes.

“Ichthyosaurs hands-down win in terms of getting to that size so early,” says Benjamin Moon, a paleontologist at the University of Bristol in England who has also studied ichthyosaur evolution.  

C. youngorum and its neighbors are all the more striking because they arrived on the scene not long after a mass extinction—one that wiped out 81 percent of all marine species around 252 million years ago. Many of the phytoplankton and algae that fuel today’s marine food chains had yet to evolve, raising the question of how the ecosystem supported such large predators.

To find out, the researchers surveyed the wealth of known fossils from C. youngorum’s Triassic ecosystem, including smaller ichthyosaurs, fish, and squid-like ammonites. The team used a computer model to investigate whether there would be enough energy to sustain C. youngorum, assuming the fossils added up to a representative picture of the ancient food chain.

Somewhat surprisingly, Schmitz says, the researchers found that the ecosystem preserved in the fossil record was “stable and well functioning” enough to support a large number of beefy marine reptiles. One clue may lie in the fact that there aren’t many fish fossils in the area. “We’re cutting out several steps in that food chain, so [there’s] more direct transfer of energy up to the top levels,” Schmitz says. 

The next step, he says, will be for researchers to explore whether body size has changed over time in similar ways among other groups of extinct and living animals that have returned to the water, including plesiosaurs and turtles. 

“It’s very neat, what they’ve done with trying to reconstruct this ecosystem,” Moon says. “That’s interesting from the point of view of saying that there’s enough food there to support these animals getting big and having diversity.”

Another question for future exploration is the extent to which other variables such as temperature might also have influenced the ichthyosaurs’ growth spurt, they say. 

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The new Omicron variant of the novel coronavirus is continuing to build momentum in the United States, and now makes up the majority of confirmed cases nationwide.

With Omicron cases doubling every 1.5 to three days in areas with community transmission, the variant is poised to fuel yet another wave of COVID-19 this winter. This has added urgency to recommendations for people aged 16 years and older who have received two doses of the mRNA vaccines from Pfizer and Moderna, or the single-dose Johnson & Johnson vaccine, to get a booster shot. 

The appearance of Omicron is both concerning and frustrating as the pandemic lurches closer to its third year, and much remains to be learned about how it works. But there is encouraging data to suggest that boosters will bolster protection against the Omicron variant, experts say.

Why do we need boosters for Omicron?

Earlier this year, public health officials had already begun to debate when booster shots might be needed for the general population.

“There was already concern that the initial two-dose series of Pfizer or Moderna was not going to provide a long-lasting durable response,” says Jason Schwartz, an associate professor of health policy and management in the Yale School of Public Health. “Omicron has shone a brighter light than ever on the urgency of shoring up those defenses.”

This latest version of SARS-CoV-2 is even more transmissible than the Delta variant of the virus. The jury is still out on whether Omicron also causes milder illness, as some early data suggested. But we do know that mutations on the variant’s spike protein—the part of the virus that COVID-19 vaccines target—help it evade antibodies generated from both prior infection and vaccination, Schwartz says.

Emerging reports from South Africa, parts of Europe, and the United States also indicate that more breakthrough cases are occurring in vaccinated people than has been the case with other variants, says Cameron Wolfe, an infectious disease physician at the Duke University School of Medicine.

However, on Monday, Moderna reported that a booster dose of its vaccine increased antibody levels against Omicron by 37 times. Earlier in December, Pfizer and its partner BioNTech said that a booster increased antibodies against Omicron by 25 times. “The data we have right now suggests that a third dose really does restore much of the antibody levels that we have seen such positive results from early in the pandemic,” Schwartz says.

In experiments that pit antibodies from vaccinated people’s blood against viruses engineered to carry the proteins found on Omicron’s surface, antibodies from those who received three vaccine doses were able to prevent the viruses from entering human cells. “That’s all theoretical, that’s all [about] binding virus in a test tube, but traditionally that’s actually correlated fairly well with clinical protection,” Wolfe says.

The antibodies and immune cells generated by COVID-19 vaccines used in the United States and beyond do seem to offer significant protection against severe illness from Omicron. However, it’s likely that only a booster dose of the mRNA vaccines will be able to block infections. 

Even if the antibodies induced by vaccination aren’t able to bind to Omicron as tightly as previous variants, the surge in numbers present after a booster shot should compensate. “There’s just more guards at the gate, even though each one is not necessarily by themselves as perfect as they once were,” Wolfe says.

Booster shots probably will not be able to quash breakthrough infections entirely. Still, Wolfe emphasizes, “Even if you were boosted and get a breakthrough, I think the important message to patients and the general community is [that] your chance of needing to come to the hospital is still meaningfully less.”

[Read More: What the Omicron surge means for your holiday travel]

When should I get my booster? 

The Centers for Disease Control and Prevention recommend that people who received their second Moderna or Pfizer dose at least six months ago, or received the single-shot J&J vaccine at least two months ago, should get a booster, ideally an mRNA vaccine.

“I would say a complete vaccine course at this point is someone who has had three doses,” Wolfe says. It’s not unusual for vaccines against other diseases to be given in more than two doses, Schwartz notes. 

You might be tempted to try to hit the three shot benchmark as quickly as possible, given Omicron’s rising threat. But if you just got your second vaccine dose a few weeks ago, or are only starting your vaccination sequence now, you shouldn’t seek out a third shot immediately. “I think you can do it too quickly,” Wolfe says. “We have seen with other vaccines that a little bit of time between doses sometimes actually is better in terms of allowing a more complete and robust immune response.”

Reynold Panettieri, the director of the Rutgers Institute for Translational Medicine and Science, advises waiting for the currently recommended time period. “My sense would be to stick with the program,” he says. “Get your first two shots if it’s an mRNA vaccine, and then get your booster in six months.”

Officials may finetune the timeline in the future. But in the meantime, there’s good news for the recently vaccinated. “Even [if they’re] not yet eligible for a booster, we know that they’ll have the high levels of antibodies that come from being so close to a second vaccine dose,” Schwartz says.

Going forward, he says, we should shift how we discuss immunization to COVID-19. “It will require us… to think less about this idea of whether one is ‘fully vaccinated,’ which is a murky concept in the best of circumstances, and talk instead about whether someone is up to date with their vaccines compared to public health recommendations.”

Unfortunately, we can probably look forward to more COVID-19 booster shots down the line as the virus continues to mutate, particularly in parts of the world where access to vaccines remains limited. “Much of that needs to be still, unfortunately, a little adaptable, because the virus has proved decidedly adaptable,” Wolfe says.

Panettieri predicts that “a jab is in everyone’s future in the next six months.” 

“Where we’re going to see innovation is when we come out with an Omicron-specific booster,” he adds. Vaccine developers have started work on updated formulations tailored to the variant, although whether regulatory agencies ultimately decide they are necessary remains to be seen. 

It’s possible that COVID-19 vaccines will eventually be updated annually to target whichever variant is currently circulating, Schwartz says, similarly to the seasonal flu shot. 

[Read More: It’s too early to dismiss Omicron as a mild COVID variant]

What else can we do to protect ourselves against Omicron?

Although the vaccines seem to provide diminished protection against infection from Omicron, their ability to stave off severe illness—particularly after a booster dose—seems to be holding up. The highly contagious Omicron variant represents the greatest threat to people who are unvaccinated, so efforts to reach these people in the United States and abroad continue to be crucial.

“We still have a significant number of people who are unvaccinated, so they become the reservoir for more severe illness, be it Delta or be it Omicron,” Panettieri says.

Meanwhile, it’s still important for vaccinated people to continue masking up, testing, and practicing social distancing, even after getting a booster. In the days before any holiday gathering, Wolfe says, it’s important to pay attention to how you feel and be prepared to cancel if you begin to show possible COVID-19 symptoms, and to be especially conscientious about wearing masks while traveling. 

“I’m a little doubled-down for the week leading up to Christmas parties to make sure I’m not the guy who brings [COVID-19] into the household,” he says. 

Panettieri is concerned that even with protection that booster doses offer against severe illness, the sheer number of Omicron cases that will soon emerge could overwhelm healthcare systems. “I think we’re really in dire straits right now, and I certainly advocate going back to masks, social distancing, disinfectants, and really trying to avoid large gatherings,” he says. “It’s sad that it’s happening over the holidays, but we have to embrace that technology again, coupling it to vaccines and leveraging the newest therapies for active infections that prevent severity of disease.”

While vaccines are crucial, Schwartz says, it’s important to remember that they aren’t our only weapon against COVID-19. 

“We know so much more about the virus and its spread, and the steps that individuals can take that come with a little disruption to their lives, but can make an important difference in protecting themselves, their families, and their communities,” he says.

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Scientists have identified an extremely rare fossilized dinosaur embryo in an egg from southern China.

The late-Cretaceous specimen belongs to a group of dinosaurs called oviraptorosaurs, which are closely related to birds. Intriguingly, the embryo’s position resembles the “tucking” posture that modern birds assume before hatching. The findings indicate that this important adaptation evolved before birds split off from other dinosaurs, the researchers reported on December 21 in the journal iScience.

“Dinosaur embryos are key to the understanding of prehatching development and growth of dinosaurs,” Fion Waisum Ma, a PhD student in paleobiology at the University of Birmingham in the United Kingdom and coauthor of the findings, said in an email. While fossilized dinosaur eggs are abundant, however, embryos are much harder to come by. The dinosaur embryos that paleontologists have found are usually incomplete, with bones that have separated and become jumbled. 

By contrast, the newly described fossil includes an almost complete skeleton with bones arranged much as they were in life. “This little dinosaur is beautifully preserved in a fossilized egg,” Ma said. “We suspect the egg was buried by sand or mud quickly enough that it was not destroyed by processes like scavenging and erosion.”

She and her colleagues were able to reveal more than half the skeleton, with the rest still covered by rocky material in the egg. The fossil, originally discovered in an industrial park in China’s Jiangxi Province, dates to roughly 71 million to 65 million years ago. The elongated egg is 16.7 centimeters (6.6 inches) long and 7.6 centimeters (3 inches) wide, while the skeleton curled inside has a total length of 23.5 centimeters (9.3 inches).

[Related: A newfound South American dinosaur had a tail like a war club]

Oviraptorosaurs have been found in present-day North America and Asia. This dinosaur family is known for its diverse variety of skull shapes, including some with very tall crests. Had the embryo hatched, it probably would have grown into a medium-sized oviraptorosaur, Ma said, perhaps reaching 2 to 3 meters (6.6 to 9.8 feet) in length. The dinosaur would have been covered in feathers and had a toothless skull. 

The researchers compared the embryo’s anatomy with that of other oviraptorosaurs and theropods, the broader category of carnivorous dinosaurs that also includes Tyrannosaurus rex. The researchers also examined a fine slice of eggshell under the microscope and analyzed the evolutionary relationships among oviraptorosaurs to determine where the new embryo fell on the family tree. They concluded that the embryo belonged to a subgroup of oviraptorosaurs called Oviraptoridae. 

“The most surprising observation is the posture of this specimen—its body is curled with the back facing the blunt end of the egg, [and] the head below the body with the feet on each side,” Ma said. “This posture has never been recognized in a dinosaur embryo, but it is similar to a close-to-hatching modern bird embryo.”

To prepare for hatching, bird embryos reposition themselves in a process known as tucking. The oviraptorid fossil Ma and her team examined is arranged much like a 17-day-old chicken embryo in the first, or pre-tucking, phase. Over the next three days, a chicken embryo would gradually move into the final tucking posture, in which the body is curled with the head under the right wing. This posture seems to stabilize and direct the head while the bird cracks the eggshell with its beak, Ma said.    

She and her colleagues suspect that several previously discovered oviraptorid embryos are also arranged in various phases of tucking, although it’s hard to be certain because those specimens aren’t as well-preserved. Still, the team concluded that oviraptorids and modern birds may have used a similar strategy to maximize their chances of hatching successfully, unlike their more distant cousins such as the long-necked sauropods and living crocodilians.

[Related: Whoa, dinosaur eggs looked more dope than we thought]

“Tucking behaviour was usually considered unique to birds, but our new findings suggest that this behaviour could have existed and first evolved among theropod dinosaurs—the ancestors of modern birds,” Ma said.

To confirm this possibility, however, researchers will have to unearth more fossilized embryos of theropods and other kinds of dinosaurs to compare with modern birds and crocodiles. Ma and her colleagues also plan to investigate the skull and other body parts of this embryo still hidden within the rock.

“We hope to answer more questions about dinosaur early development and growth with this exceptional specimen,” she said.

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A group of enigmatic little skunks have a characteristic move: Seconds before they spray, the animals flip into a handstand, and spew their noxious chemical compounds while upside down. Known as spotted skunks, these animals have always been a bit of an enigma to researchers, and now a team of scientists has identified three new species that belong to this distinctive group of skunks. 

Scientists analyzed the DNA of spotted skunks collected from across North America, and found that several populations previously considered subspecies were in fact distinct enough to deserve a promotion. The findings have implications for efforts to conserve the rarer members of the group, the researchers reported on September 1 in Molecular Phylogenetics and Evolution.

“There are a lot of places where spotted skunks are not doing particularly well at all,” says Samantha Wisely, a wildlife ecologist at the University of Florida in Gainesville who was not involved in the research. “They’re these incredibly cryptic and very shy species, and so we just don’t know a lot about them and that makes them really hard to conserve.” Now, she says, this new paper provides evidence that there are far more distinct species of this animal than we realized.  

Spotted skunks are smaller than the striped skunks that many people are more familiar with, and covered in white patches that are actually broken-up stripes, says Adam Ferguson, a collection manager of mammals at the Field Museum in Chicago and coauthor of the paper. “They are everybody’s favorite; they are adorable,” he says. “I call them the acrobats of the skunk world because they’re really good climbers [and] they can do the handstand.”

Scientists have debated just how many spotted skunk species roam the continent for over a century, with estimates ranging from two to 14. In recent years, four species have been recognized: respectively, the western, eastern, southern, and pygmy spotted skunk. They differ in appearance primarily by size and the pattern of their white markings, Ferguson says. 

He and his colleagues thought that a more thorough look at the genetics of spotted skunks might reveal some additional members hiding within the four known species. Gathering enough skunks to analyze proved to be a challenge, though. This was partly because the agile skunks can be difficult to find and catch, and partly because of their protective stench. 

“Collecting and saving them from roadkill is not what everyone likes to do,” Ferguson acknowledges. “When we found them [dead] on the road, we actually had to bag them and then hang [the bags] out the trunk…because if you put it in your car, your car is going to smell like that for the rest of the time you own the car.”

Ultimately he and his team compiled 203 tissue samples from both recently collected skunks and older museum specimens, along with samples from several other kinds of skunks for the sake of comparison. 

The researchers next examined the skunks’ DNA. First, they looked at the nucleus, the part of the cell containing the majority of genetic material. They also analyzed the mitochondria, which are the energy-producing cellular structures that contain their own circular DNA. Analyzing both types of DNA allowed the researchers to build a more complete picture of the skunks’ evolutionary history, Ferguson says.

He and his colleagues found that there were actually seven different species of spotted skunks. They determined that the pygmy spotted skunk split off from the common ancestor of the rest of the group about five million years ago. 

[Related: The five smells Americans hate most (and how to get rid of them)]

Then, around 1.5 million years ago, this ancestor split into western and eastern populations, which each eventually gave rise to three different species. These splits were likely driven by the expansion and retreat of glaciers—whose icy bulk acted as a barrier to isolate spotted skunk populations from each other—during the Pleistocene Ice Age.

The western group became the Rocky Mountain and desert spotted skunks (both known in previous family trees as the western spotted skunk), as well as the southern spotted skunk. The eastern group splintered into the prairie and Allegheny spotted skunks (formerly both called the eastern spotted skunk), as well as the Yucatán spotted skunk. 

The prairie spotted skunk has declined significantly across the Great Plains in recent years. Recognizing this population as a full species could help it gain protections under the Endangered Species Act. “This is a much older, more distinct evolutionary lineage, which implies that it warrants conservation,” Ferguson says.

The findings may also shed light on a phenomena seen in some spotted skunk populations known as delayed implantation, which allows the animals to mate in fall and then wait to give birth until the spring. 

“They can hold onto a very, very early stage embryo and delay the implantation of it [in the uterus] to really delay pregnancy until it’s a much better time to actually have a baby and raise it,” Wisely says. Understanding how and why spotted skunks diverged into new species can “help us understand what are some of the evolutionary triggers to facilitate this…process.”

There may still be more spotted skunk species waiting to be identified, Ferguson says. In the future, he and his colleagues hope to get their hands on more skunks from the southwestern United States, Mexico’s Gulf Coast, and across Central America. He’s particularly interested in the tropical forests of the southern Yucatán Peninsula.

Skunks can be found across North America, Ferguson says, but “we still don’t know everything there is to know about them…it’s worth continuing to dig deeper in our own backyards as well as other places to figure those things out.”

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At long last, scientists have discovered a millipede that lives up to its name and actually has 1,000 legs. 

The unique critter was found deep underground in Western Australia and boasts up to 1,306 legs—more than the paltry 750 legs previously documented in millipedes, or indeed any other animal. The newly-named Eumillipes persephone and the dethroned previous record holder probably both evolved their seemingly excessive number of limbs to shove themselves through narrow spaces in the soil, the researchers reported on December 16 in Scientific Reports. 

E. persephone’s subterranean environment is imperiled by mining activities, making conservation efforts critical, says Paul Marek, an entomologist at Virginia Tech and coauthor of the findings. 

“These undiscovered fauna are living in a realm that was previously thought to be devoid of life, but also an ecosystem that we really rely on for screening of environmental toxins and also filtering our water,” he says. “So by studying the organisms that live in these ecosystems, we can help conserve biodiversity on this planet but also help preserve the environment.”

Although the term millipede literally means “thousand feet,” most species actually have fewer than 100 legs, Marek says. The arthropods have been around for more than 400 million years, with some extinct members reaching 2 meters (6.6 feet) in length. Millipedes play an important role in their ecosystem by feeding on decaying organic matter. 

The new species comes from an area dotted with drill holes used to prospect for gold, nickel, and other minerals. These holes also offer scientists a portal to a remote and unexplored environment. To find out what might be crawling belowground, Bruno Buzatto, of Macquarie University in Sydney and the University of Western Australia in Perth, and his colleagues lowered in cups baited with rotting leaf litter to attract hungry invertebrates.

When the researchers withdrew a cup from a depth of 60 meters (almost 200 feet) in August 2020, they spied a pale, thread-like millipede. Suspecting that the creature might be packing more legs than any known species, the team reached out to Marek, a millipede specialist. When he examined several specimens, Marek realized that he was looking at “a true millipede.” He counted a whopping 1,306 legs sprouting from 330 ring-like segments in a female member of the species, and up to 818 legs and 208 rings in males (female arthropods tend to be larger than males, Marek says, the better to carry more eggs). 

[Related: Glowing millipede genitalia give scientists a leg up in the lab]

In addition to observing the millipedes under a powerful scanning electron microscope, the researchers took DNA samples from E. persephone and compared its genome to those of other species. This confirmed that E. persephone was only a distant relative of the 750-legged Illacme plenipes, which is found in California. The findings indicate that super-elongated bodies evolved independently several times in millipedes that thrive underground.

“Extra legs translates to extra pushing force,” Marek says. “This is coupled with their highly extensible and compressible body, which is amazingly good at squeezing into crevices.”

E. persephone—which is named for the Greek mythological goddess Persephone, who was taken to the underworld by Hades—displays a number of other characteristics suited for its life beneath the surface. The cream-colored millipede lacks both pigmentation and eyes, but has a cone-shaped head with “enormous” antennae and a beak for feeding, the researchers wrote. The females can grow to 0.95 millimeters (0.04 inches) in width and 95.7 millimeters (3.8 inches) long. 

In the future, Marek will search for other ultra leggy millipedes in the southwestern United States. “Folks in Phoenix and Tucson have reported super-elongated millipedes that occasionally come up in their backyard when it’s extremely rainy,” he says. 

More work is also needed to understand the underground habitat E. persephone and many other invertebrates call home. Scientists wouldn’t have discovered the record-breaking millipede without the drill holes necessary to the very mining practices that may threaten it, Marek notes.

“We’re trying to avoid this phenomenon of anonymous extinction, where a species goes extinct without us knowing about it and without it being described,” he says. “[Anonymous extinction] is  a potential in a lot of areas, in particular where we found this millipede.”

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Around 120 million years ago in what is now northeastern China, there lived a bird that may have possessed the unusual ability to stick its tongue out. 

Scientists described a nearly complete skeleton of the ancient bird, which they named Brevirostruavis macrohyoideus, on December 1 in the Journal of Anatomy. The fossil’s extremely elongated tongue attachment bones, or hyoid apparatus, suggests that the bird could protrude its tongue from its mouth, much as some present-day birds do to grab hard-to-reach morsels.

Brevirostruavis highlights how both modern birds and their extinct relatives have developed a plethora of ways to secure a meal, says Robert Kambic, an assistant professor of biology at Hood College in Frederick, Maryland, who was not involved with the research.

“Birds were evolutionarily experimenting with a bunch of different types of feeding adaptations and strategies early on,” he says. “That’s just a cool thing, that this diversity of habits and feeding modes is not unique to living birds, but in fact seems to be representative of the whole bird line.”

In humans, the U-shaped hyoid sits at the base of the tongue, just above the voicebox. “That bone is not attached to any other bone, and it’s floating suspended by muscles that attach to it from a bunch of different directions,” Kambic says. “Some of the muscles of the tongue need this anchor point, especially if you think about sticking your tongue out and retracting it.”

Birds typically lack the muscular, agile tongues enjoyed by humans, although a few do have fleshy tongues that help them peel fruits or seeds with their beaks. And in a few families, parts of the hyoid apparatus and beak are elongated, allowing the birds to poke their tongues out. Hummingbirds use their nimble tongues to slurp up nectar from deep within flowers, while woodpeckers extend their tongues to pull insects or sap from trees. 

“Woodpeckers are the extreme,” Zhiheng Li, a paleontologist at the Chinese Academy of Sciences in Beijing and coauthor of the findings, said in an email. “Their tongues are so long that they actually wrap around the top of their heads and even enter one of their nostrils.”

The newly-reported Brevirostruavis belongs to a diverse group of early birds called Enantiornithes, which have no living representatives but were the dominant birds around the world during the Cretaceous Period. The specimen was discovered preserved in a slab of rock from China’s Liaoning Province dating to the early Cretaceous. Brevirostruavis was about the size of a starling, and its long claws and the proportions of its toe bones hint that the creature was a tree-dweller.

When the researchers examined the Brevirostruavis fossil, they also identified an odd combination of features not seen in other living or extinct birds. 

In today’s birds, the hyoid apparatus consists of cartilage and several bones, including the rod-shaped ceratobranchials and epibranchials. Modern birds that can stick their tongues out have especially long epibranchial bones, as well as elongated beaks. Early birds didn’t have these bones; in Brevirostruavis, it’s the ceratobranchials that are curved and run nearly the length of its skull. 

More perplexingly, Brevirostruavis also had a short, pointed snout, which was lined with peg-shaped teeth. This unique pairing—a very long hyoid apparatus and short snout—could have several explanations, Kambic says. 

“Rather than trying to get the tongue as far out as it can, the long muscle attachment could also be good for a muscular tongue that’s really needed…to either maneuver food around within the mouth or close to the mouth,” he speculates.

Another possibility is that Brevirostruavis did indeed use its impressive hyoid to stick its tongue out, but some evolutionary constraint prevented the bird from elongating its beaklike snout. “So it has this long tongue without a commensurate beak to help it out,” Kambic says. “It has one part of the system, whereas a living bird might have two parts of the system that would work together.”

[Related: Were rocks on the menu for these ancient birds?]

Brevirostruavis may have been able to take advantage of food sources that other birds were unable to access, although the lack of preserved remains from the specimen’s last meal makes it difficult to be sure what it ate. Still, it’s possible that Brevirostruavis used its tongue to explore the bark of trees for hidden insects or to reach the nectar-like fluids and seeds in the reproductive cones of prehistoric plants, Li said. 

The team also analyzed the evolutionary relationships between Brevirostruavis and its relatives. They found that Brevirostruavis didn’t fit with any of the major groups of enantiornithines, indicating that the elongated hyoid apparatus evolved independently multiple times across the bird family tree. 

“Many of the same problems related to flying and eating today were present 120 million years ago, and that is why we see some of the same features evolved in such distant relatives of the birds around us today,” Li said.

Next, the team plans to examine several other fossil birds that also seem to have had fairly long tongues and to search for more Brevirostruavis specimens. “We also want to see if we can determine when the epibranchial bones evolved in birds, because those bones are pivotal for the long tongues present in living birds,” Li said.

Investigating how modern birds use their hyoid apparatuses might also shed light on why Brevirostruavis evolved its unusual combination of a short snout and long tongue bones, says Kambic, who studies how bones and muscle work together in living animals.

Nonetheless, he says, much can be learned from the skulls and tongue bones of bygone animals like Brevirostruavis. 

“[They] can potentially give us some nice specific insights in terms of what these animals were eating,” Kambic says. “And that gives us information about their day-to-day lives in a more direct way than some of the other bones of the rest of the body might be able to tell us.”

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An encouraging new experiment hints that cutting off mercury pollution to bodies of water can quickly translate into lower levels of the toxic substance in seafood.

Scientists tracked how mercury levels in fish and invertebrates in a Canadian lake changed over 15 years. During the first seven years, the researchers seeded the lake with mercury. Once the influx of new mercury ceased, the team found, contaminant levels quickly fell in both small and large fish within a few years. 

“As a demonstration, it tells us that policies that reduce mercury pollution will be effective and that mercury concentrations would be a lot higher in the absence of these policies,” says Paul Blanchfield, a research scientist at Fisheries and Oceans Canada. He and his colleagues reported the findings on December 15 in Nature.

Although the element is naturally occurring, a great deal of the mercury in the environment comes from human activities such as mining or emissions from coal-fired power plants, Blanchfield says. It can be transported long distances in the atmosphere before being rained down onto lakes and rivers or the watersheds that feed them. Once mercury gets into aquatic ecosystems, some of it will be transformed by microbes into an extremely poisonous chemical called methylmercury. 

“It tends to increase with every step in the food chain,” Blanchfield says. “The fish at the top of the food chain are the ones we humans eat, and they have the highest concentrations of methylmercury—often up to a million times higher than in [the surrounding] water.”

Most people have small amounts of methylmercury in their bodies that are too miniscule to cause health issues. At higher levels, however, this powerful neurotoxin can impair speech, hearing, walking, and vision.

[Related: Researchers found signs of human pollution in animals living six miles beneath the sea]

Demonstrating a clear link between reducing mercury pollution and lower methylmercury levels in fish has proven difficult, Blanchfield says. That’s because many variables influence how methylmercury is produced and accumulates in food chains, including human-related disruptions such as commercial fishing and the arrival of invasive species.

To understand the impacts of controlling mercury, the researchers visited the International Institute for Sustainable Development’s Experimental Lakes Area, which comprises dozens of small lakes in remote northwestern Ontario that have been set aside for scientific research. They zeroed in on a small lake populated by northern pike; their prey, yellow perch; and lake whitefish, which forage along the bottom of the lake.

For seven years, the researchers added different forms, or isotopes, of mercury to the lake surface as well as to nearby upland and wetland areas. This allowed them to disentangle the effects of newly-added mercury from different sources around the lake, and from older mercury that had been accumulating in the lake for many years. The team found that methylmercury concentrations rose by 45 to 57 percent in lake-dwelling invertebrates and small fish, and more than 40 percent in larger fish. 

Most of the mercury the researchers measured in these animals had been added directly to the lake. The researchers didn’t detect any mercury from the wetland, and only very small amounts from the upland area, Blanchfield says.

After the researchers stopped adding mercury to the lake, the team found that the isotopes they’d introduced decreased by 81 percent in lakewater, 35 percent in lakebed sediments, and 66 percent in tiny zooplankton within three years. By the end of the experiment, methylmercury made from these isotopes had dropped more than 85 percent in small fish, 76 percent in pike, and 38 percent in whitefish populations.

When the researchers analyzed tissue samples taken from the same fish over time, they found that mercury levels didn’t decline much in individual animals. “Fish do hang onto their mercury for a while,” Blanchfield says. “However, when we looked at the entire population we saw that it was declining quite rapidly.” This indicates that young fish, which weren’t exposed to the more polluted environment of the study’s early years, are driving the population’s recovery, he says. 

The researchers also noticed that methylmercury declined more slowly in the bottom-feeding whitefish than in the lake’s top predator, the pike. This is likely because the whitefish are larger, longer-lived fish that reproduce more slowly than the pike, Blanchfield says. 

Still, the speed at which the fish populations responded to the decreased amount of mercury coming into lakes came as a pleasant surprise to the researchers. “We thought it could potentially keep contributing for quite some time,” Blanchfield says.

That said, he cautions, it may yet take awhile for mercury from the wetland and upland areas to find its way into the lake. “What we did see is when that mercury got into the lake, it responded just like the mercury we added to the lake surface: It went up quickly and came down quickly,” Blanchfield says. “That tells us that [for] any amount we can reduce mercury coming into lakes, whether it’s through direct deposition through rain onto the lake surface or by runoff, you should see a fast response in the fish populations.”

This information is crucial for efforts to manage mercury contamination, says John Rudd, another coauthor of the findings and former chief scientist at the Experimental Lakes Area.

“Essentially we found that ‘mercury is mercury,’” Rudd said in an email, adding that “Policy makers need to write regulations that control the total mercury loading to lakes, not just the mercury that enters directly from the atmosphere.”

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This story has been updated. It was originally published on September 3, 2021.

In August, the Centers for Disease Control and Prevention urged all people who are pregnant, breastfeeding, or considering pregnancy to get vaccinated against COVID-19. The updated recommendations were based on a new analysis, the agency said, which had followed thousands of vaccinated participants through pregnancy. According to new data released this week by the CDC, there appeared to be a spike in deaths among pregnant people in the months of August and September, as the Delta variant was sweeping across the country. Now, as the Omicron variant continues to spread, the CDC is concerned about pregnant people who are still unvaccinated.

Pregnant people are especially vulnerable to the novel coronavirus, and the ongoing and ferocious spread of the highly contagious Delta variant has highlighted just how crucial it is to get immunized. According to the recent CDC report, nearly half the deaths among pregnant people since the start of the pandemic occurred in the month of August. The number of pregnant people who contracted COVID-19 also increased drastically in August of 2021.

COVID-19 poses an increased risk for pregnant people. Data collected by the CDC since the start of the pandemic and updated as recently as December 3, 2021, shows that infection with the virus increases the risk of both stillbirth and preterm birth. Through the early months of the vaccine’s rollout in the United States, though, some unvaccinated people have remained uncertain over concerns that the shots could lead to infertility. 

“That’s a big reason why a lot of individuals are hesitant to take it if they’re thinking about becoming pregnant,” says Marc Incerpi, chief of the Division of Maternal-Fetal Medicine with Keck Medicine of USC in Los Angeles. Fortunately, he emphasizes, researchers and physicians have found no evidence that the vaccines impact a person’s ability to conceive or have a healthy pregnancy. 

“Now there’s a fair amount of data that shows that these things really are just myths,” says Richard Beigi, president of the UPMC Magee-Womens Hospital in Pittsburgh. “The bottom line is that there is absolutely no link at all whatsoever, either theoretical at this point or in reality, with any impact on fertility.” 

The misconception that COVID-19 vaccines harm female fertility has been fed by several sources. When the majority of Americans were getting vaccinated back in the spring, some people reported irregular or heavy periods after their shots. Researchers have been looking into the possibility that the vaccines might temporarily disrupt the menstrual cycle, but these changes, if there were any, would be short-lived and wouldn’t affect a person’s fertility.

[Related: Vaccination cuts the risk of long COVID in half]

Another piece of misinformation is likely connected to a letter sent by two anti-vaccine advocates to the European Medicines Agency back in December. The myth claims that the vaccines would cause the body to generate antibodies that would mistakenly attack a placental protein called syncytin-1 because of its resemblance to the spike-shaped protein on the surface of the novel coronavirus. However, the two proteins share only small bits of genetic code, Jill Foster, a pediatric infectious disease specialist at the University of Minnesota in Minneapolis, told WebMD in January. Foster likened the proteins to two phone numbers that both happen to contain the number seven. Even if syncytin-1 really were similar to the coronavirus spike protein, then it should be vulnerable to antibodies produced by unvaccinated people who’d caught COVID-19. “You would think that [these] antibodies would also cause issues with infertility, and we just haven’t seen that,” Incerpi says.

Furthermore, in experiments where scientists exposed samples of antibodies formed after infection or vaccination to the syncytin-1 protein, there was no detectable reaction. 

For its August 2021 report, the CDC analyzed data from its v-safe COVID-19 Vaccine Pregnancy Registry, which includes participants who were vaccinated against COVID-19 shortly before or during pregnancy. The agency found no increase in the risk of miscarriages among nearly 2,500 expectant women who received an mRNA vaccine before 20 weeks of pregnancy.

Last month, the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine, and other preeminent medical organizations also released a joint statement strongly encouraging pregnant people, as well as those who were recently pregnant or planning to become so, to get vaccinated. The COVID-19 vaccines have no impact on fertility, the statement said.

“They’ve looked at fertility rates, they’ve looked at pregnancy rates, they’ve looked at issues as it relates to complications or adverse outcomes from pregnancy and the vaccine, and at least to this point there hasn’t been anything to be concerned about,” Incerpi says.

Meanwhile, Beigi and his colleagues are currently working on a study to “accumulate even more data” by tracking vaccinated women during and after their pregnancies. The team hopes to have preliminary results by the end of the year. 

“But the available data at this point is very reassuring,” Beigi says. “That’s why both ACOG and the CDC felt comfortable going from a passive recommendation to an active recommendation for [vaccination during] pregnancy.”

Another crucial consideration is that people who are, or recently were, pregnant face an increased risk of becoming seriously ill or dying if they do catch COVID-19. Pregnant people with COVID-19 also have an increased risk of preterm birth, according to the CDC.

As the delta variant has taken hold over the last few months, Incerpi says, “Pregnant women are getting it at higher numbers, and they’re getting sicker.” For pregnant people who do remain unvaccinated, he says, “It’s really important that they still practice the social distancing, the mask wearing, and all those other things that we know help mitigate the spread of infection.”

In addition to protecting pregnant people from becoming seriously ill, the COVID-19 vaccine may also come with another benefit. Researchers have found antibodies to COVID-19 in umbilical cord blood from pregnant people who received an mRNA vaccine. 

“This means COVID-19 vaccination during pregnancy might help protect babies against COVID-19,” the CDC has said. “More data are needed to determine how these antibodies, similar to those produced with other vaccines, may provide protection to the baby.”

It’s not entirely surprising that the myth that COVID-19 vaccines harm fertility has taken off. 

“Reproduction is a very sensitive issue for so many people,” Beigi says. “If you want to sow doubt, pick something that people are already…sensitive about.”

Some people may also be wary because women’s health concerns often haven’t been taken seriously throughout history, he acknowledges. “I think it’s kind of a deeper issue than what it looks like at face value,” Beigi says.

[Related: All your COVID booster shot questions, answered]

Others have voiced concerns that there hasn’t been enough long-term data on the vaccines, Incerpi says. It’s normal for researchers to continue monitoring the safety and efficacy of vaccines after they are approved. However, “there really is no plausible reason to expect that there would be an adverse outcome years down the road,” Incerpi says. 

The novel coronavirus, on the other hand, poses an immediate danger. Last week, the number of people in the United States hospitalized with COVID-19 reached a daily average of 100,000 for the first time since January, causing ICU beds to run out in many locations.

Meanwhile, the pace of vaccination has started to accelerate in the United States, the Washington Post reported this week. Millions more people got a first COVID-19 vaccine dose in August compared with July.

“I think the delta variant has reinvigorated people’s desire” to get vaccinated, Beigi says. “I’ve also seen that…in pregnant women.”

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Decreases in vehicle emissions have prevented thousands of deaths across the United States in recent years, a new analysis suggests. 

Scientists used emissions reports and epidemiological data to estimate that deaths caused by air pollution from cars, trucks, and other vehicles fell from 27,700 in 2008 to 19,800 in 2017. They calculated that this shift yielded $270 billion of benefits related to reduced mortality (a measure based on mortality risk) and averted greenhouse gas emissions in 2017 alone. 

However, while emissions from heavy-duty trucks have substantially waned, the picture was less rosy for smaller vehicles, particularly in urban areas. The findings indicate that more work is needed to ease the disproportionate health burden that traffic emissions place on cities, the researchers reported on December 13 in Proceedings of the National Academy of Sciences.

“It strengthens the case for looking at alternatives like electric vehicles, increased public transportation, or biking or walking,” says Ernani Choma, a research fellow in environmental health at the Harvard T.H. Chan School of Public Health. 

Vehicle exhaust contains a host of pollutants such as sulfur dioxide, nitrogen oxides, and fine particulate matter (particles less than 2.5 microns, or roughly 1 ten-thousandth of an inch, in size). Chronic exposure to these compounds has been linked to health problems including respiratory issues such as worsened asthma, cardiovascular disease, and premature death. Some of the gases that vehicles release from their tailpipes, like carbon dioxide, also contribute to climate change.

[Related: One way to cut down air pollutants: call an Uber]

Since the Clean Air Act was passed in 1970, emissions of common pollutants have been slashed by as much as 99 percent per vehicle, according to the Environmental Protection Agency. But despite these drastic reductions, vehicle emissions have remained an important public health and climate issue, Choma and his colleagues noted. 

They investigated the benefits of decreases in vehicle emissions in the contiguous United States from 2008 to 2017. The researchers gathered detailed emissions, mortality, and population data from the EPA, the Centers for Disease Control and Prevention, and Department of Health and Human Services and analyzed how fine particulate matter levels affected the mortality risk of different age groups. 

The researchers calculated that vehicle emissions were responsible for 19,800 deaths in 2017, down from an estimated 27,700 deaths in 2008. But when the team explored a hypothetical scenario in which per-mile vehicle emissions remained at 2008 levels, they estimated that 48,200 deaths would have occurred in 2017. In other words, 2008 emissions levels would have caused more deaths in 2017 than they did in 2008. 

“You would have a much bigger effect,” Choma says. There are several reasons for this, he says, including an aging population that is more vulnerable to air pollution and a rise in bulkier passenger vehicles such as SUVs and pickup trucks.

“If those trends of large vehicles and higher population continue in the future, we’ll need more stringent policies to be able to make more progress [in reducing deaths],” Choma says.

He and his colleagues also calculated the “social cost” of vehicle emissions, based on common approaches used to determine how much people are willing to pay to slightly decrease their risk of dying from threats such as environmental pollution, as well as the economic impacts of greenhouse gas emissions. They calculated that damages attributable to vehicle emissions reached $260 billion in 2017. Had emissions stagnated at 2008 levels, however, the team estimated that the damage would have totaled $530 billion.

The researchers also observed that emissions from heavy-duty trucks decreased more sharply than those from smaller vehicles. In metropolitan areas alone, emissions from passenger vehicles such as cars and SUVs were responsible for about 30 percent more deaths than all heavy duty trucks in the United States. “Most of these deaths are not caused by the very large, heavy-duty trucks; it’s passenger vehicles in large urban areas that are important now,” Choma says.

One limitation of the findings is that the researchers focused on the overall societal impact of vehicle emissions, Choma says.

“We know that this air pollution burden is not equally distributed,” he says. “Racial and ethnic minorities…often suffer from higher exposure to air pollution, so it would be good to enact policies that would reduce these inequities.”

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The young star EK Draconis, which lies 111 lightyears from Earth, is about the same size and temperature as our own sun. However, it’s currently a much more turbulent place, a new report indicates.

Scientists observed EK Draconis as it hurled a burst of plasma into space that proved more massive than any previously recorded for a sun-like star. Our sun may have had similarly powerful storms in its past, which could have left their mark on Earth and its neighbors, the researchers concluded on December 9 in Nature Astronomy.

Our sun periodically gives off explosions of radiation known as solar flares. The flares are sometimes accompanied by eruptions of superheated matter, or plasma. These events are called solar storms or coronal mass ejections. Occasionally, the clouds of plasma reach Earth’s magnetic field to interfere with satellites and cause blackouts; in 1989, the entire power grid in the Canadian province of Quebec was taken out by a solar storm.

But our sun has calmed down a lot over its 4.6-billion-year lifespan, says Yuta Notsu, an astrophysicist at the University of Colorado Boulder and coauthor of the study.  Previous work by Notsu and his colleagues indicates that particularly impressive “superflares” are most common in young, rapidly rotating stars but may occur once every few thousands years or so on older stars like our sun.

“The sun is an average middle-aged, boring star; the flares aren’t really that energetic,” says Damian Christian, an astrophysicist at California State University Northridge who was not involved with the research. “We can study more active stars [and] we might apply what we learn from them to the sun.” 

Enter EK Draconis. The star is a sprightly 50 to 125 million years old and can offer a glimpse of what the sun might have looked like billions of years ago.

Notsu and his team observed EK Draconis from January to April 2020 using observations from ground-based telescopes as well as NASA’s Transiting Exoplanet Survey Satellite. On April 5, the star lit up with a large superflare. Shortly afterwards, the researchers detected a distinctive shift in the wavelengths of light picked up by the telescope. “From this we can conclude that a large amount of plasma is away from the star moving towards us,” Notsu says. 

He and his colleagues estimated that the plasma bubble was traveling at speeds up to roughly a million miles per hour and had a mass 10 times greater than the largest ejections from our sun.

[Related: Violent space weather could limit life on nearby exoplanets]

The researchers make a good case for the telescope observations being explained by a coronal mass ejection coming from EK Draconis, Christian says. “It’s a very nice result,” he says.

Although the findings are interesting, says Rachel Osten, an astronomer at the Space Telescope Science Institute and Johns Hopkins University, “What would be more convincing is multiple events…and maybe multiple methods that are showing these kinds of results.”

In the future, Notsu and his colleagues plan to search for more stellar outbursts and to track what happens to the plasma as it moves away from the surface of its star. “We only detected an initial phase,” he says. “We don’t know how it evolved.”

Still, he says, the coronal mass ejection that he and his team observed can help scientists understand how these storms unfold on distant stars and our sun. It’s possible that plasma erupted from the ancient sun damaged Mars’s atmosphere, which today is much thinner than that of Earth, Notsu speculates.

Stellar storms could have a big impact on whether a planet becomes habitable, Osten says. If the plasma reaches a planet’s magnetic field, its destructive effects can leave the atmosphere vulnerable to harsh ionizing radiation. 

Just because a blob of plasma is flung away from a star doesn’t mean that it’s going to hit one of the planets orbiting that star, though, Osten acknowledges. Still, she says, coronal mass ejections highlight how important it is to consider what goes on beyond a potentially Earth-like planet’s atmosphere when searching for alien life.

“This line of investigation is telling us that it’s all interlocked,” she says. “You can’t just focus on the planets, you’ve got to understand the stars because they’re an important ingredient in that recipe for what can make life.”

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Climate change is causing glaciers around the world to melt, which in turn worsens sea level rise and disrupts ocean currents and coastal ecosystems. But for some fish, there may be a small silver lining. 

Scientists used computer models to simulate how meltwater will feed new streams and lakes across western North America, and found that retreating glaciers could create thousands of miles of new habitat for Pacific salmon by the end of the century. Understanding where and when these piscine frontiers will emerge will be key for future conservation plans, the researchers reported on December 7 in Nature Communications.

“This showcases how climate change is fundamentally transforming ecosystems; what is now under ice is becoming a brand new river,” says Jonathan Moore, who leads the Salmon Watersheds Lab at Simon Fraser University in British Columbia and coauthored the new findings. “We can’t just manage for current salmon habitat, we also need to think about how we can manage for future salmon habitat.”

Glacial retreat does pose a threat to salmon in some areas. “It can decrease the air conditioner effect that glaciers have on downstream rivers, so rivers will be getting warmer during the summer,” Moore says. And as glaciers shrink, less seasonal meltwater is available to feed these rivers in summertime. However, when glaciers melt away from valley bottoms they can create new streams. “The rivers will be lengthening as the glaciers will be retreating up the valley, and other work has found that salmon can find and thrive in these newborn river systems,” Moore says.

He and his colleagues investigated how this might play out in the coming decades across a 623,000-square-kilometer (240,542-square-mile) region stretching from southern British Columbia up into Alaska. About 80 percent of the glacier-covered territory in North America’s Pacific mountain ranges fall within the range of Pacific salmon, which support subsistence harvests and fisheries worth billions of dollars annually. 

Led by Kara Pitman of Simon Fraser University, the researchers identified 315 retreating glaciers at the headwaters of existing streams that could create a habitat that salmon would be able to reach. The team then estimated when and where those glaciers would retreat under several climate change scenarios. “The next phase was to use predictions of what the land looks like underneath the ice…[to] imagine the future rivers in these future salmon habitats,” Moore says. 

The researchers calculated that by 2100, Pacific salmon will have access to 6,146 kilometers (3,819 miles) of new streams. Much of this habitat will come from areas with large, low-lying glaciers near the coast, such as the Gulf of Alaska and Copper River.

[Related: Salmon are dying off and your car tires might be to blame]

The team also explored which parts of the aquatic network would provide suitable habitat for the fish to spawn and rear young salmon, based on the expected steepness of the stream channels. They found that about 1,930 kilometers (1,199 miles) of the burgeoning streams could offer gently sloping conditions ideal for the salmon.

As glacier ice disappears, more of the northern landscape will become available to mining and other industries. Forecasting where new salmon habitat is likely to open up may allow researchers to identify areas in need of protection, the researchers concluded.

However, Moore says, this will be a complicated undertaking. He and his team estimated how much potential habitat melting glaciers could create, but didn’t analyze how temperature and other environmental conditions could render new streams more or less inviting for the salmon. 

Another complication is that salmon don’t spend all their time in freshwater habitats; they’re also tied to the sea. “If the ocean is increasingly unsuitable because of the warming that has created new freshwater habitats, that will not lead to more salmon populations,” says Peter Westley, an associate professor in the ​​College of Fisheries and Ocean Sciences at the University of Alaska Fairbanks. Westley is a co-leader of the Salmon Science Network Initiative, which provided funding for the research, but wasn’t involved directly in the current study. “You need both suitable ocean and available and suitable freshwater habitats.”

Moore wants to make it clear that the research doesn’t mean salmon will thrive as Earth warms. Salmon are facing many climate-related burdens, including marine heat waves, ocean acidification, and extreme floods and droughts. “The paper does not suggest that climate change is good for salmon,” Moore says. “It’s possible that these local opportunities might be overshadowed by large-scale declines in salmon populations.”

And even if salmon do move into new areas where glacial ice has waned, there will be consequences for people who depend upon the fish. 

“The shifting distribution of salmon, while good for the salmon, does not address those really stark and pressing societal and cultural issues of the loss of salmon in certain rivers,” Westley says. “That does not help the person that’s on their river and seeing their salmon disappear because it’s too warm.”

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For a group of small aquatic animals known as hydra, decapitation is more an inconvenience than anything else. Thanks to the creatures’ incredible regenerative abilities, it needn’t be fatal. 

The processes that govern how hydra manage to regrow their heads have remained mysterious, however. Hoping to understand the genetic underpinnings of this feat, scientists have taken a close look at which genes are switched on and off during regeneration and how they’re controlled. 

“We wanted to know…what is happening at the genome level that’s telling these cells to grow or stop growing, and how does that compare to normal development?” says Aide Macias-Muñoz, an evolutionary biologist at the University of California, Santa Barbara, who undertook the research while at the University of California, Irvine.

She and her colleagues found key differences in head growth during regeneration and budding, the form of asexual reproduction used by hydra and some other animals such as corals. The team also noted that some of the mechanisms involved in hydra regeneration are similar to those that control development in other animals. This could mean that these “developmental tools” have an ancient history within the animal kingdom, says Macias-Muñoz, who published the findings on December 8 in the journal Genome Biology and Evolution.

Hydra belong to a larger group of invertebrates called cnidarians, which also includes sea anemones, corals, and jellyfish. Their simple bodies have a tubelike shape with the mouthpart and tentacles at one end, and a “foot” that attaches to the surrounding rock or other solid surface at the other. 

Some animals such as lizards and salamanders can regrow lost limbs. But hydra, along with some worms and other animals, take regeneration to the extreme. Near their mouthparts, hydra have a cluster of 50 to 300 cells called the head organizer; as its name implies, it directs the development of the head. If a hydra is beheaded, a new organizer can form and prompt the animal to regrow its head. Meanwhile, the head that was lopped off will sometimes regrow the lower portion of its body. 

Scientists have also successfully grafted hydra heads onto the decapitated bodies of other hydra. And if a hydra is torn into small clumps of cells, those clumps that include head organizer cells will regrow a full body, Macias-Muñoz says.

She and her team investigated whether hydra follow similar instructions to build their heads during regeneration and budding (in which the animal grows a little bud that eventually detaches to form an entirely new hydra). They analyzed tissue samples taken from hydra undergoing both processes, and identified 298 genes that were expressed differently during head regeneration and budding. These included genes previously linked to head organizer formation in hydra, as well as genes involved in the regeneration process in other animals. 

[Related: These jellyfish seem to cheat death. What’s their secret?]

“Regeneration and budding, even though you get the same result, take different trajectories,” Macias-Muñoz says.

She and her colleagues also examined the mechanisms that control whether the instructions in these genes are carried out during regeneration. They homed in on the animals’ chromatin, tightly-packed genetic material that consists of DNA and proteins. When a stretch of chromatin is “closed,” proteins called histones keep it wrapped up so the DNA within cannot be read; when chromatin is “open,” other proteins can bind to and transcribe the DNA.

“Some areas of the chromatin are open in certain times of regeneration, and in other times they’re closed,” Macias-Muñoz says. “So it’s not only that genes are being turned on and off, it’s also that this changing of the open or closed chromatin is helping regulate the expression of these important genes for regeneration.”

The researchers also identified regions within the chromatin that are known to bind proteins that play important roles in development across different animal species. This suggests that some of the genetic machinery underlying regeneration evolved before the cnidarians split from the ancestors of more “complex” animals such as humans, Macias-Muñoz says. 

The findings raise an intriguing question, she says. Does tissue regeneration work very similarly in hydra and other animals? Or are animals such as lizards and salamanders “rewiring” developmental genes in unique and different ways to achieve a similar effect as hydra?

In the future, Macias-Muñoz will explore how the genes and control processes she and her team identified interact. “The next step would be to actually functionally test them and verify that they are doing something in regeneration,” she says. 

Investigating how regeneration works in simple organisms like hydra, and how similar it is to processes in other animals, could potentially lead to insights about how development goes awry in humans.

“Studying hydra just gives us a fundamental look at what cells can do and what the mechanisms are at the gene level,” Macias-Muñoz says. “If we can figure out how to disrupt them or fix the disruption in other organisms, then maybe we could start to think about how those disruptions that happen and cause disease can be…treated differently.” 

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Every year, at least 14 million tons of plastic garbage enter the world’s oceans and cause all kinds of problems for the wildlife that eat, suffocate on, or become entangled within it. There’s also another consequence of all this trash for marine habitats that’s been mostly overlooked until now, scientists reported this week.  

It turns out that coastal plants and animals are hitching a ride on the ever-growing deluge of plastic debris and traveling hundreds of miles from shore to create a new kind of ecosystem in the Great Pacific Garbage Patch, the largest accumulation of moving plastic debris in the ocean. Researchers identified a host of anemones and other species living within the rubbish, which allows the little creatures to thrive in an otherwise inhospitable environment. The coastal organisms may compete with local species and journey across the sea or be carried to the shore to invade new coastlines, the team wrote on December 2 in Nature Communications. 

“There are so many questions at this point about what the ecological impacts are,” says Linsey E. Haram, a research associate at the Smithsonian Environmental Research Center and coauthor of the study. “If this is a common phenomenon across oceans, then we’re looking at an avenue for invasive species transport that’s really difficult to manage.”

Researchers have long understood that marine detritus such as floating logs and seaweed can ferry coastal organisms to islands and distant shores. But these rafts were generally rare and short-lived before the advent of durable, buoyant plastics. It was thought that coastal plants and animals would struggle to survive in the harsh conditions of the open ocean, where there’s often little food and shelter.

However, the glut of plastic that’s accumulated in the ocean since the mid 20th century has given enterprising critters new and more enduring opportunities to colonize the high seas, Haram and her team wrote. The massive East Japan Earthquake and Tsunami of 2011 offered a striking example of how this can happen. Hundreds of coastal Japanese marine species rode the debris released by the destruction over 6,000 kilometers (3,728 miles) to North America’s west coast and the Hawaiian Islands. 

“We’re still finding examples of tsunami debris landing even in 2020 and 2021,” Haram says. “It really opened our eyes to the fact that plastics in particular can be really long-lived as floating debris, which opens up opportunities for some of these rafting species to be out in the open ocean for extended periods of time.”

Much of the waste washed out to sea by the tsunami ended up in the North Pacific Subtropical Gyre, better known as the Great Pacific Garbage Patch. The gyre, which lies between Hawaii and California, is formed by rotating ocean currents and has, over the past 50 plus years, become a reservoir for plastic litter of all sizes.  

[Related: The great Pacific garbage patch is even trashier than we thought]

Haram and her colleagues wanted to find out whether any coastal marine life from the tsunami was still clinging to this trash. They worked with the Ocean Voyages Institute, a nonprofit that cleans up plastic pollution, and volunteers to collect debris larger than 5 centimeters (about 2 inches). The researchers then combed through samples of the garbage—which included buoys, derelict fishing gear, and household items such as hangers and toothbrushes—for signs of life.

They found coastal species attached to well over half of the plastic pieces they examined, and many were species that typically thrive in eastern Asia. Among them were anemones, brittle stars, barnacles, shrimp-like crustaceans called isopods, seaweeds, and even coastal fish that were “corralling around or on these floating plastics,” Haram says. “It really creates a little raft of life.”

Alongside the coastal creatures were organisms that have evolved to settle on marine floating debris or animals. These open ocean dwellers included gooseneck barnacles, crabs, and filter-feeding animals called bryozoans. Intriguingly, Haram says, these native rafters were actually less diverse than the array of coastal species her team identified. 

The findings suggest that the blend of lifeforms thriving on plastic rafts in the middle of the ocean are a community in their own right, says Henry S. Carson, a marine ecologist at the Washington Department of Fish and Wildlife who wasn’t involved with the research.

“You’ve got this mix of species that are evolved to be [in the] open ocean and evolved to be coastal, and now they’re mixing on this new kind of habitat,” he says. “I couldn’t predict what will happen, but it’s fascinating.”

The two groups do seem to be competing for space, but beyond that it’s not clear yet how the coastal species interact with their neighbors or what they’re eating, Haram says. She and her colleagues are also investigating whether the new arrivals can actually reproduce and sustain their populations in the open ocean.

“To figure out how much of this community is persisting on its own and how much is being constantly imported from the coast…would be a natural and very interesting place to go,” Carson says.

[Related: This luxurious fabric breaks down in the ocean without leaving a trace]

Another key question is whether these communities form in other oceans. It’s also important to investigate the extent to which plastic rafts carry invasive species to new habitats, points out Carson, who has previously identified organisms that cause disease in corals on plastic debris from the Pacific Ocean.

It’s likely that these rafting communities will only become more prevalent in the future as the amount of plastic dumped into the sea continues to grow, and flooding and destruction along coastlines worsens due to increased storminess driven by climate change, Haram and her colleagues concluded.

“We’re looking at more opportunities for inoculation of plastics into our oceans, and what that will mean for open ocean communities time will tell,” Haram says. “But we can expect to see more and more plastic ending up in the middle of the ocean and if our research is any indication that may mean more coastal species as well.”

Correction: 12/7/2021; A previous version of this story incorrectly credited Smithsonian Institute in the opening image, which is incorrect. Credit should have gone to The Ocean Cleanup. The image caption has also been updated to clarify that not all hydroid animals are coastal.  

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On September 19, the Canary Islands’ Cumbre Vieja volcano began an explosive eruption that shows no signs of letting up anytime soon. A series of earthquakes provided only about a week’s warning ahead of the disaster, which has forced around 6,400 residents to evacuate and destroyed more than $450 million worth of infrastructure.

But a preliminary analysis of seismic data suggests that unrest leading up to the eruption actually became detectable four years before the volcano blew its top. Understanding how this volcano, which had been dormant for 50 years, reactivated could help improve future eruption forecasting and volcanic hazard assessments, says Marc-Antoine Longpré, a volcanologist at Queens College in New York, who published the findings on December 2 in Science.

“That’s the rationale for looking at this—hoping that in the future when the volcano wakes up again…we will be better prepared to say what might happen and over what kind of period of time,” he says.

Scientists have tracked seismic signals at volcanoes that are regularly active such as Hawaii’s Kīlauea and Sicily’s Mount Etna to investigate how the time between eruptions relates to how long it takes for the volcano to reactivate. But this has been harder to do with volcanoes that remain dormant for long periods like Cumbre Vieja, which is located on the island of La Palma in the Atlantic Ocean. Despite being the most active volcano in the Canaries, it’s only erupted six times over the past 500 years. 

[Related: Why the aftershocks from Haiti’s earthquake could be incredibly destructive]

Since the volcano’s last outburst in 1971, Spain’s Instituto Geográfico Nacional and the Instituto Volcanológico de Canarias have built seismic monitoring networks to record data from Cumbre Vieja and other sites in the archipelago. “It’s the first time that we witness with modern instrumentation its reactivation,” Longpré says.

He pored through this data to find out how many earthquakes had occurred per month since 2000, and observed very little seismic activity until a swarm of earthquakes occurred in October 2017. Another cluster of earthquakes took place in February 2018. Then, after a break of several years, the earthquake swarms began to pick up again in 2020 and 2021. These earthquakes were mostly too small to be felt by the people above, but mark the earliest signs that the volcano was getting ready to erupt, Longpré says.

This slow awakening stands in contrast to the much shorter runup times that are typically observed at this kind of basaltic volcano, he says. It’s possible that other volcanoes with long quiescent periods may also have subtle but protracted warning periods as well. 

“Volcanoes have their own personalities, so next time it could do something a little bit different,” Longpré says. “But at least we know there’s a precedent now.”

The tiny earthquakes were caused when magma began to invade and break apart rocks miles beneath the volcano. A mere eight days before the eruption began, the seismic activity accelerated as the magma moved closer to the surface and caused the ground to swell. “That’s an additional clue that the magma was on the move and quite shallow beneath the volcano,” Longpré says. 

During this final week, the earthquakes picked up by seismic instruments increased to several hundred daily, became large enough for residents to take notice, and migrated to the northwest. Finally, two 200-meter-long (219-yard-long) fissures opened up on the volcano’s northwestern flank near the village of El Paraèso and began spewing lava and ash. 

Over the next six weeks, lava flows demolished around 2,600 buildings, more than 70 kilometers (43.5 miles) of road, and 2.3 square kilometers (0.9 square miles) of crops. Meanwhile, the ash rose up to 6 kilometers (3.7 miles) above sea level–higher than researchers would have expected from records of past Canary Islands eruptions–and within a month had fallen and accumulated up to 60 centimeters (23.6 inches) in some locations. 

In the future, analyzing the chemistry of rocks ejected from Cumbre Vieja and closer examination of the seismic records could reveal more details about how the volcano prepared for the violent eruption, Longpré says, which could help researchers and officials prepare for future events. 

“Eruption forecasting is an imprecise science,” he acknowledges. “What we observed is really useful, however that is not to say that in the future when volcanoes like Cumbre Vieja reactivate they [mightn’t] behave differently.”

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A new species of armored dinosaur from subantarctic Chile boasted a large tail weapon that looked dramatically different from those found on its relatives, and may shed light on a mysterious phase in the group’s evolution. 

Scientists found the mostly-complete skeleton in 2018 in the Río de las Chinas Valley of Chilean Patagonia and determined it to be roughly 71.7 to 74.9 million years old, dating it to the late Cretaceous. When they further examined the skeleton, the researchers found a baffling mixture of features typically seen in ankylosaurs and stegosaurs. However, its “bizarre” tail didn’t seem to match with the tails seen in either of these famous groups; rather than the traditional spikes or clubs, the newly-named Stegouros elengassen had seven pairs of bony deposits encasing half the tail in a flattened frond-like structure, the researchers reported on December 1 in Nature. 

Still, an analysis of the armored dinosaur family tree revealed that the fossil belonged to an ankylosaur, suggesting that different branches of the group flourished in the northern and southern hemispheres after the supercontinent Pangaea broke up. 

“This is the first time scientists get a good look at what a South American ankylosaur is like,” says Alexander Vargas, a paleontologist at the University of Chile in Santiago and coauthor of the study. Stegouros’s tail weapon, he adds, is “absolutely unlike anything we have seen before.”

A number of present-day mammals and reptiles, including porcupines and alligators, use their tails as whips or lashes to defend themselves from predators or rivals. But southern African girdled lizards go a step farther: Their tails are equipped with bony spines. More elaborate versions of these tail armaments were once wielded by extinct relatives of turtles and armadillos. 

“But the champions of them all are the armored dinosaurs,” Vargas says. In addition to the bony plates and spines along their backs, some members of this group developed specialized tail weapons. These included the tail spikes seen in stegosaurs such as Stegosaurus and rounded tail clubs belonging to ankylosaurs such as Ankylosaurus.

The ankylosaurs generally had broad backs and thick limbs. While ankylosaur fossils are plentiful in North America and Asia, Vargas says, until now only fragmented bones and teeth have been found of their more southern cousins. 

“These scraps and pieces were often interpreted as a sign that ankylosaurs, which in North America were very abundant and diverse, somehow managed to cross into South America, to migrate,” he says.

The specimen that he and his colleagues discovered in 2018 at the southern tip of South America changes this picture, Vargas says. When the team began to excavate the fossil, they first noticed its slender limbs and speculated that the specimen might have been a bipedal herbivore. Next came the tail with its “astonishing weapon,” Vargas says, which indicated that the skeleton actually represented some kind of armored dinosaur. 

“We thought we might have a stegosaur when we uncovered the hips,” he says. “They were identical to a stegosaur.” The fossil’s upper arm and right hand also resembled those of stegosaurs. Yet when the team reached the skull, they found that the upper jaw and palate looked distinctly ankylosaurian.

[Related: An overlooked fossil turned out to be a new herbivorous dinosaur with an oddly shaped nose]

To find out which group the puzzling species belonged to, the researchers analyzed hundreds of different traits from dozens of dinosaur species and ultimately identified ​​Stegouros as an ankylosaur. What’s more, its ancestors split off from the rest of the ankylosaurs some 167 million years ago in the mid-Jurassic. 

“It’s an evolutionary link between the ankylosaurs…and other armored dinosaurs like the stegosaurs,” Vargas says. 

This could explain why Stegouros bears so little resemblance to most ankylosaurs, with its agile limbs, narrow feet, light armor, and a hawk-like beak. The petite ankylosaur was only about 2 meters (6.6 feet) long and had a shorter tail than other armored dinosaurs. The weapon’s flattened shape might have made it easier for Stegouros to avoid dragging its tail and “being able to wield it for defense,” Vargas says. He and his colleagues named the structure after an Aztec war club, or macuahuitl, which resembles a wooden sword with obsidian blades protruding from either side.  

The researchers determined that Stegouros is closely related to two other ankylosaurs from Australia and Antarctica. The latter, which is known as Antarctopelta, features “enigmatic” bony plates that have perplexed scientists but which might be part of the same kind of macuahuitl used by Stegouros, Vargas says.  

The findings suggest that Stegouros “is not an invader from the north,” he says. “It is actually a lineage that has roots so deep in time it’s [from] when all continents were together.”

As Pangaea finished separating into Laurasia (present-day North America and Eurasia) and Gondwana (which would become South America and the remaining continents) in the late Jurassic, the more familiar ankylosaurs would come to dominate the northern continent while Stegouros and its relatives laid claim to the south. 

For their analysis, Vargas and his team only described a single Stegouros specimen. They plan to search for more complete skulls in the future that can be compared with those of the ankylosaurs from Antarctica and Australia. The findings also emphasize how little is still known about the evolutionary history of armored dinosaurs in the southern hemisphere, the researchers concluded.

“You can expect more surprises from the south,” Vargas says.

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An odorless chemical emitted by humans and other mammals might trigger more combative behavior in women and lessen aggression in men, according to a study published last week in Science Advances. 

Scientists observed how people reacted to frustrating computer games in the presence and absence of the molecule, known as hexadecanal. Female players took more retaliatory action against their opponents while sniffing the chemical, while men showed the reverse pattern. The team also noted differences between how brain activity changed in men and women during exposure.

The experiments indicate that chemical signals we aren’t consciously aware of may influence our behavior in certain contexts. However, the findings come with several caveats—and more evidence is needed to verify the extent to which hexadecanal actually influences us.

“This definitely needs to be replicated before it can be really fully accepted and generalized,” says Ashok Panigrahy, a professor of radiology, developmental biology, bioengineering, and bioinformatics at the University of Pittsburgh, who was not involved in the research. However, he says, “this study highlights the importance of smell, and how it relates to behavior.” 

For most mammals, aggressive behavior is very sensitive to the effects of chemical signals. But little is known about how these processes work in humans, says Eva Mishor, a neuroscientist at the Weizmann Institute of Science in Rehovot, Israel and coauthor of the new findings.

Previously, scientists have reported that hexadecanal reduces stress in mice, while other research has shown that humans release the compound in our feces, skin, and breath, and that it might affect our startle response.

To investigate whether hexadecanal might play a role in human aggression, Mishor and her colleagues ran several experiments in which volunteers played computer games with a mysterious partner. Unbeknownst to the players, this “partner” was actually a computer algorithm designed to provoke them. 

In the first experiment, 67 men and 60 women were treated unfairly in a game that involved divvying up a small sum of money. The participants later had the opportunity to blast their uncooperative partner with a loud burst of noise, the volume of which they controlled. During the games, each participant wore a sticky pad pasted to their upper lip, half of which contained hexadecanal.

“We saw there was a small yet highly consistent difference between the groups,” Mishor says. 

Women exposed to hexadecanal indulged in more severe noise blasts than women who weren’t exposed, she says, while men who were exposed to the chemical opted for less intense noise blasts than those who weren’t.

[Related: We have now seen our sense of smell in action]

The researchers then explored whether the same individual might behave differently while sniffing hexadecanal than in its absence. This time, 25 men and 24 women endured a different aggravating game in which their computer opponent occasionally stole money from them; in turn, the players could also dock money from their partner without gaining it themselves. The researchers tracked how often the participants chose to do this and took fMRI scans of their brains. The team found that on average, women reacted more aggressively when hexadecanal was wafted through the scanner, and men less so. 

In both groups, a part of the brain called the left angular gyrus (which is involved in perceiving social cues) became activated during exposure to the chemical. However, a difference between the sexes emerged when the researchers examined how this region “talked” to other parts of the brain. 

When men were exposed to hexadecanal, activity in the left angular gyrus became more synced with that in several other brain areas involved in processing social information and aggression: the temporal pole, amygdala, and orbitofrontal cortex. But in women, connectivity between the left angular gyrus and these other regions decreased during hexadecanal exposure. 

The findings indicate that these areas “form some kind of a social and emotional-decision making network,” Mishor says. The findings could shed light on different brain mechanisms underlying aggressive behavior in men and women, she adds.

Mishor and her colleagues offer one explanation for the differences in how women and men responded to hexadecanal. “Perhaps the one setting in which it could be highly beneficial to reduce male aggression and increase female aggression is the setting of infant-rearing,” she says.

In other species, Mishor and her team wrote, mother animals often direct their aggression at intruders while fathers and especially other males often behave aggressively toward the infants. Hexadecanal could give babies a tool to increase their odds of survival, they speculate.

As a first step to investigating this idea, the researchers analyzed the chemicals emitted from the heads of 19 babies and detected hexadecanal in all but two, noting that the compound was one of the most abundant molecules they detected. 

“Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers,” the researchers concluded in the paper. However, they acknowledge, this explanation “remains to be experimentally verified, and here serves only as an example of possible ecological relevance for our results.”

A story of smell

The research also had several other important limitations. Mishor’s team didn’t measure how much hexadecanal humans actually emit, or how this amount differs between babies and adults. It’s not clear yet under what circumstances adults release hexadecanal or how much of this molecule is inhaled by other people. And although the researchers identified brain activity patterns associated with exposure to hexadecanal, they didn’t show that this activity was actually responsible for making people behave more or less belligerently. 

On top of all this, hexadecanal isn’t the only chemical that babies give off. To find out whether hexadecanal does indeed play a role in parental aggression, Mishor says, the team will need to test it along with the rest of the compounds in human baby odor.

The findings support the idea that hexadecanal is a pheromone, or substance that animals use to communicate with other members of their species. “The study moves us towards understanding how this chemical can affect human behavior,” says adds Royce Lee, an associate professor of psychiatry and behavioral neuroscience at the University of Chicago, who wasn’t involved in the research. “I wouldn’t go so far as to say that we know that this will affect parental behavior, or how we behave outside of the laboratory.”

[Related: Young mice learn to parent by babysitting]

It remains to be confirmed whether the sex difference that Mishor and her team observed would remain in future experiments with larger numbers of volunteers. More generally, claims on sex-based differences brain structure and activity have been shown to be largely unreliable, with recent research suggesting that our brains are individual “mosaics” of “female-typical and male-typical features.” “Nonetheless, Lee says, the results are “certainly very interesting and provocative.”  

“One question is, does this give us some clues about what can reduce human aggression?” he says. “I could see one pathway in the future to study this chemical and to see if we can learn something about how to help with human aggressive behavior.”

Mishor, Lee, and Panigrahy all agree that the findings have implications for our understanding of the mysterious connection between the nose and brain. 

“Human olfaction is one of the most primordial senses,” Mishor says. “It is wired differently in the brain than other senses, and it many times bypasses consciousness and impacts us without us being aware of the effect.”

The researchers focused on a very specific type of behavior in their experiments, raising the intriguing question of whether the chemical might be relevant for other kinds of social situations, notes Panigrahy, who is currently studying how olfaction influences social behavior in people who have congenital heart disease.

The findings may have particular resonance as the world continues to deal with COVID-19, which can impair people’s sense of smell, he says.

“This is a really important topic from the perspective of what we’re going through now,” Panigrahy says. “Understanding how olfaction relates to social behavior from a bigger context is so relevant to our current era.”

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Bees may need multiple generations to recover from the lingering impacts of pesticide exposure, according to a new study. 

Scientists at the University of California, Davis tracked how blue orchard bees that encountered chemical-laced nectar and pollen as larvae or adults fared over two years. The researchers found that exposure early in life could impair reproduction, as could exposure during adulthood. However, the effects were especially dramatic in bees that faced a double whammy of pesticide exposure as youngsters and adults; these unlucky insects produced 44 percent fewer offspring than bees that were never exposed to the chemical. 

These delayed, or “carryover,” effects should be taken into account for future conservation efforts, the team reported on November 22 in Proceedings of the National Academy of Sciences.

“We have a better understanding now of the way pesticide exposure affects bee populations over time,” says study co author Clara Stuligross, a PhD candidate in ecology at UC Davis. “This really shows that pesticide exposure to bees in agricultural areas is additive, and exposure to pesticides in multiple years has a greater effect than just a single exposure.”

Pesticides are one of many threats contributing to declining insect populations. “But mostly the studies have focused on the current effects of pesticide exposure, despite the fact that pesticides could affect organisms long after direct exposure,” Stuligross says. “That’s where we came in.”

She and her colleague Neal Williams decided to investigate the long-term impact of pesticides on blue orchard bees, a common species in North America that pollinates crops such as almonds and cherries. Unlike honeybees and bumblebees that live in large colonies, blue orchard bees are solitary, with each female responsible for collecting pollen and nectar to provision her own offspring.

In agricultural areas, pesticides are often applied several times a year. This means that bees in these areas will likely come into contact with the chemicals at multiple stages of their life cycles and over multiple years, Stuligross says. 

To recreate these conditions, she and Williams allowed groups of captive bees to forage from flowers with or without pesticide treatment. The following year, they divided up the bugs’ grown offspring; once again, some groups foraged on pesticide-treated flowers and some did not. The team then counted how many offspring the insects produced. 

[Related: 5 ways to keep bees buzzing that don’t require a hive]

They found that bees exposed to insecticide as adults were slightly less likely to produce offspring and constructed their nests more slowly than other bees. Overall, they raised 30 percent fewer offspring than bees that didn’t encounter the chemical as adults. 

For individuals that had only been exposed as larvae the previous year, the damage was more subtle. The bees’ nesting behavior was unaffected, but they had 20 percent fewer offspring compared with bees without past exposure. “It means that it can sometimes be hard to detect these carryover effects,” Stuligross says. “It may be easy to miss them if you don’t look all the way through the life cycle.”

Bees that had fed on tainted pollen and nectar as larvae, and were then exposed again as adults, had 44 percent fewer offspring than bees that had never faced the insecticide. Overall, their population growth rate was 72 percent lower than that of the unexposed bees, the researchers calculated.

The pesticide that Stuligross and Williams used, a common one in the US known as imidacloprid, affects the nervous system and has been shown to interfere with bees’ learning ability, behavior, and physiology, she says. It’s likely that the chemical harms bees in multiple ways that collectively hinder their reproduction, foraging, and ability to build nests.

“We just looked at one little slice of how this one pesticide exposure could affect bees,” Stuligross says, noting that the study focuses on just one bee species and a single type of pesticide—in the wild, bees are often exposed to many chemicals at once. In the future, she will investigate how pesticides and other stressors, like limited food and the emergence of parasites, work together to influence bee populations.

Understanding the delayed effects that pesticides can inflict on bees and other pollinators will help researchers plan better guidelines for how, when, and where to apply the chemicals in ways that harm the critters as little as possible, Stuligross says.

“We can enable practical actions to mitigate these risks,” she says. 

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This post has been updated. It was originally published on November 26, 2020.

If you have a sumptuous feast to look forward to on Thanksgiving Day, it might be tempting to share the bounty with your pet. But it’s a bad idea. A lot of ingredients that might show up in your holiday spread (or unguarded trashcan) are dangerous goods for pets. Dogs, being more inclined than cats to scarf down human food, are especially vulnerable.

When holiday foods don’t agree with a pet, they often cause vomiting and diarrhea, as well as more debilitating symptoms. So keep a close eye on your pets, and make sure to keep them away from these items in particular.

Grapes

Grapes and raisins are poisonous to dogs (cats rarely eat them.) They can cause vomiting and diarrhea before shutting down the kidneys.

Vets aren’t sure why this happens, or why some dogs seem to be more likely to get sick. “We would recommend treatment even if they only got into a few grapes and raisins,” says Erica Reineke, a professor of emergency and critical care medicine at the University of Pennsylvania’s School of Veterinary Medicine.

Treatment can include making the dog throw up and giving him activated charcoal to prevent more poison from being absorbed. “If they come in immediately and we’re able to induce vomiting and decontaminate them and support them with some IV fluids, it’s pretty uncommon that we end up seeing kidney failure,” Reineke says.

Onions

Garlic, onions, chives, or leeks may spice up stuffing and other side dishes, but they are dangerous for both dogs and cats. These foods damage the membranes of red blood cells, leading to anemia. “The red blood cells basically pop,” says Reineke.

After eating onions, pets might experience vomiting, diarrhea, weakness, pale gums, or a high heart rate. It can take awhile for symptoms to show up. “They may eat a bunch of onions and you think everything’s okay, and then two days later the dog or cat starts acting lethargic,” Reineke says.

Poisoning from onions happens less often than with other holiday foods. “We see it, but it’s certainly less common than chocolate, grapes, and raisins,” Reineke says.

Bones and fats

If your dog manages to swallow a bone, there’s a chance it will lodge in the intestines and need to be surgically removed.

Poultry bones can also splinter and irritate the esophagus or gastric lining. “If they’re just in the stomach and they stay there, they’ll eventually dissolve most of the time,” Reineke says.

[Related: Dog supplies your pet will love]

Turkey skin is another font of gastrointestinal distress, as are gravy and fatty foods (like butter-drenched mashed potatoes or stuffing). “Worst case scenario, that can cause inflammation of the pancreas,” Reineke says. This condition, called pancreatitis, can be life-threatening.

Sweets

Cats show little interest in desserts, but several treats can endanger dogs. Chocolate is the usual suspect, particularly dark or baker’s chocolate. One 2017 study found that pups are most likely to get chocolate poisoning on Christmas—but that study was done in the U.K, and it’s reasonable to imagine that in the U.S., Thanksgiving doesn’t lag too far behind. Any occasion when numerous desserts sit out amidst general household chaos is potentially dangerous.

How much damage chocolate does depends on a dog’s weight and how much they’ve eaten. “If they eat one Hershey’s kiss that’s probably not an issue,” Reineke says. You should check how much they’ve consumed and call a vet for advice, or use an online dose calculator to make sure they’re not in peril.

Chocolate contains theobromine, a substance similar to caffeine, which, at higher doses, can cause vomiting, diarrhea, an elevated heart rate or blood pressure, and even, rarely, seizures and coma. “They might be anxious, they might be running around more than they normally would, ” Reineke says.

Another troublemaker is xylitol, an artificial sweetener that sometimes appears in baked goods. It can cause a dangerous drop in blood sugar or, in some dogs, liver failure.

Alcohol

Booze and rum-soaked cakes are not a good way to share your festive spirit with your pet. Like people, animals can suffer from alcohol poisoning, and may experience vomiting, falling blood pressure and body temperatures, loss of coordination, or coma.

[Related: Catnip and grapefruit are ushering in a new era of insect repellants]

Another, less obvious source of alcohol: yeast dough. If your dog gobbles up uncooked bread dough, it can continue to rise in the stomach, fermenting and releasing alcohol. This can also lead to bloating or even a twisted stomach.

Are any Thanksgiving foods safe?

If you are worried about something your pet might have eaten, you can contact a veterinarian or call the Pet Poison Hotline or ASPCA Animal Poison Control Center.

Even if a dish isn’t toxic, it’s still probably not ideal for your furry friends. “We would discourage pet owners from giving table food at any time because it can cause GI upset if it has a lot of fat in it and they’re not used to eating it,” Reineke says.

Still, there is one Turkey Day staple that might actually do your pet some good: pumpkin is full of fiber, so it’s sometimes used as a remedy for constipated dogs. But if you’re not trying to make Fido and Fluffy poop, it’s best to give them treats of their own.

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A mysterious fossil previously thought to be a four-legged snake is actually an ancient lizard, a new analysis suggests. 

Researchers first identified the roughly 120 million-year-old specimen from Brazil as a snake in 2015, based on its skull and other skeletal features. But now, after examining the rock containing the tiny reptile, another international team of scientists concluded that it was misclassified. 

The ongoing debate surrounding the species, named Tetrapodophis amplectus, has implications for our understanding of the evolutionary history of snakes. It also touches on important ethical issues related to studying a fossil that was likely illegally exported from Brazil, the researchers wrote on November 18 in the Journal of Systematic Palaeontology.

“We wanted to challenge the science as it was originally published and also to restart the discussion around the species and its repatriation back to Brazil,” says Michael Caldwell, a vertebrate paleontologist at the University of Alberta and coauthor of the new paper.

Scientists have long searched for fossils that would help illuminate how early snakes transitioned to a limbless body plan (a feature also shared by some modern lizards and amphibians). And indeed, researchers have identified several early snakes that still possessed hind limbs. So the idea of a missing link between snakes and their lizard ancestors is hardly surprising.

“But in the case of Tetrapodophis, the anatomy just does not support the animal being interpreted as an ancient four-legged snake,” Caldwell says. “Therefore what we see doesn’t tell us anything about the origins of snakes or the evolutionary progression of body elongation, limb loss, and skull specialization in snakes.”

The specimen is thought to have come from the fossil-rich Crato Formation in northeastern Brazil and dates to the early Cretaceous Period. The exact circumstances are murky, but it’s likely that Tetrapodophis was collected without permits and left Brazil through the illegal fossil trade, Caldwell says. The fossil now resides in a private collection, raising additional ethical concerns about studying specimens that aren’t widely accessible (both teams of researchers were able to examine Tetrapodophis while it was on loan to a museum in Germany). 

[Related: These snakes wiggle up smooth poles by turning their bodies into ‘lassoes’]

“It’s really important for people to acknowledge the origin of specimens, because they come from a place that is not lost in time,” says Tiago Rodrigues Simões, a paleontologist at Harvard University and coauthor of the new study, who is from Brazil. “It’s actually a region where people live and it’s part of the local heritage.”

Returning Tetrapodophis to a Brazilian collection is crucial “not just to fulfill what the law requires, but also as part of standard ethical practices,” he says.

A serpentine debate

When scientists first described Tetrapodophis in 2015 in the journal Science, they noted features that may have been adaptations for burrowing, constricting, and opening its mouth wide enough to swallow large prey, similar to those seen in modern snakes. 

Caldwell, Simões, and their colleagues interpreted the specimen differently. 

A major  difficulty the researchers have run into is that the Tetrapodophis skull is very poorly preserved. “When the slab was split open to reveal…the specimen inside, most of the material from the right side of the skull was lost, and the left side is just a shattered mass of eggshell-thin bone,” Caldwell says. Examining the impressions in the natural mold created by the rock surrounding the fossil, however, allowed the team to investigate the skull in more detail.

Based on the shape and positions of the jaws and eyes, they determined, the reptile bore more resemblance to lizards than snakes. And while Tetrapodophis would have been flexible, the researchers didn’t find evidence that its vertebrae were particularly suited for constricting. The team also concluded that Tetrapodophis‘s skinny, flattened body was more ideal for aquatic habitats than burrowing, not unlike those of eels and modern sea snakes. The reptile may have used its stubby limbs for steering while it swam, they wrote. Also suggestive is the fact that the specimen was found in sediments that were deposited in a lake, Caldwell says.

He and his colleagues also analyzed the reptilian family tree to predict where Tetrapodophis might have fit in. They found that it likely belonged to a group of extinct marine lizards called dolichosaurs, which are closely related to snakes. 

Tetrapodophis would have been an “extremely tiny little animal,” Caldwell says, although until more specimens are discovered it remains uncertain whether it was a fully-grown adult. The fossil is only 19.5 centimeters (7.7 inches) long, and its “incredibly skinny” form is suggestive of “chubby spaghetti,” he adds. 

Not everyone is convinced by the new report.

“There’s certainly room for debate about some aspects of the skeleton—in some places the bones are broken, or covered up by the rock, so the shape of some bones isn’t clear,” Nicholas Longrich, a paleontologist at the University of Bath in England and coauthor of the 2015 paper, told Popular Science in an email. “But overall I still think the anatomy is far more consistent with the animal being related to snakes.”

Deciphering the family relationships of this fossil are critically important, he emphasizes. “As the oldest and most primitive snake, it has a lot to tell us about early snakes—what they looked like, how they lived, where they lived,” Longrich said. “I don’t think this paper will end the debate about snake origins.”

Even if Tetrapodophis isn’t a four-legged serpent, though, the fossil is intriguing for other reasons, including its supremely elongated shape, paddle-like limbs, and an “inordinate” number of vertebrae compared with most snakes and lizards, Caldwell says. 

“What Tetrapodophis is informative of is an unsuspected level of diversity in the evolution of elongation and limblessness in lizards,” he says. “It’s unique on its own without being a snake.”

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A second person with HIV seems to have cleared the infection without stem cell treatments, raising optimism for efforts to develop a cure or vaccine. Researchers could find no evidence of intact virus in the patient, a 30-year-old woman from Esperanza, Argentina who’d been diagnosed eight years prior. 

“Examples of such a cure that develops naturally suggest that current efforts to find a cure for HIV infection are not elusive, and that the prospects of getting to an ‘AIDS-free generation’ may ultimately be successful,” Xu Yu, of the Ragon Institute of Massachusetts General Hospital, MIT, and Harvard, told CNN in an email. 

Yu and her colleagues reported the findings on November 15 in Annals of Internal Medicine. The team previously described the first-known person—a 67-year-old woman named Loreen Willenberg—to naturally achieve this so-called sterilizing cure last year in the journal Nature. Additionally, two other cases of a sterilizing cure have been reported in people with HIV who received bone marrow transplants (also known as stem cell transplants).

About 38 million people are currently living with HIV, which if untreated causes AIDS. During infection, HIV inserts copies of its genetic material, known as proviruses, into the DNA of the host’s own cells. This creates a viral reservoir that allows HIV to hide from the immune system. 

Antiretroviral therapy can prevent the virus from replicating, thereby reducing the amount of HIV in the blood, or viral load, to undetectable levels. However, it doesn’t get rid of the viral reservoir.

Yu and her team have spent years studying a group of people called elite controllers, who maintain viral reservoirs but can keep the infection under control without antiretroviral drugs. Some individuals are also able to suppress the virus after they stop treatment. In the incredibly rare instances of a sterilizing cure, though, the person has apparently eradicated the viral reservoir, whether through stem cell transplants or their natural immune response. 

The newly-reported Esperanza Patient was diagnosed with HIV in 2013. She didn’t receive regular treatment except while pregnant and ultimately delivered an HIV-negative baby in March 2020. The researchers examined more than 1.5 billion cells in blood and placental tissue samples taken from 2017 to 2020. They found only seven defective proviruses. 

It’s possible that the virus is still lurking in some organ that the researchers weren’t able to test, says Luis Montaner, leader of the HIV research program at the Wistar Institute in Philadelphia, who wasn’t involved in the research. This means that scientists cannot be 100 percent certain that a sterilizing cure has taken place.

Nevertheless, “this individual has no evidence of the potential to have an intact copy from which the virus would be read and produced,” Montaner says. “Now the question is, how did this happen?”

Several aspects of the Esperanza Patient’s case are intriguing. She received a negative HIV test in 2011 and was presumably infected later by her partner, who was carrying a substantial viral load when tested in February 2013. It’s unclear how long or to what extent she might have been exposed to the virus before herself becoming infected. The Esperanza Patient’s immune system may have built up some degree of resistance to the virus during this window, Montaner says. If so, her experience could provide insights for HIV vaccine development. 

[Related: The first mRNA-based HIV vaccine is about to start human trials]

When the researchers analyzed the genetic sequence of the handful of defective proviruses they’d detected, they found distinctive mutations that suggest the virus had time to evolve to resist the immune system’s initial defenses. This raises another exciting possibility. 

“We’ve always had the notion that once the virus starts to evolve and replicate there’s no turning back, meaning that the virus is in, period,” Montaner says. But if the Esperanza Patient managed to eradicate the virus even after this point, he says, “There is more hope that the immune system can be more powerful than HIV if adequately stacked against the virus.”

Yu told CNN that it’s likely many parts of the immune system working independently contributed to the Esperanza Patient’s success. Uncovering more people who may have naturally achieved a sterilizing cure would help shed light on how the immune system could be galvanized to quash the virus.

“This report is really exciting in multiple dimensions, but it also raises a lot of questions that we cannot answer with a single case,” Montaner says. 

Still, “this gives us a lot of hope about the future for a cure,” he adds. “It says we’re not chasing something that is impossible.”

The case of the Esperanza Patient may even have implications for research on other viral illnesses that are adept at evading the immune system.

“The answer to this outcome is likely tied to a very basic immune mechanism,” Montaner says.

“If that’s the case, then that is transferable across the board.”

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Summer heat waves could increase the number of fires that sweep through California’s Sierra Nevada mountain range by more than 50 percent by the 2040s, scientists reported this week.

When the researchers examined data on past weather conditions and fires, they discovered that a disproportionate share of fires occurred on sweltering days. This isn’t surprising, but as extreme temperatures become more common due to climate change, the researchers predict, this danger will only grow.  

The findings underscore the threat posed by increasingly hot and dry summers, the team wrote on November 17 in Science Advances.

“It’s pretty alarming that we’re going to see pretty high increases in both the number of fires and burned area just because of small increases in temperature from these heat waves [that last] for a couple days,” says Aurora Gutierrez, a project scientist in Earth system science at the University of California, Irvine and coauthor of the findings.

Wildfires have been a part of the western North American ecosystem for millions of years. However, the rise of fire suppression policies in the early and mid-20th century have allowed denser, more flammable vegetation to increase, ultimately setting the states for more intense blazes. Climate change is also worsening fire seasons across California. The number of fires and amount of burned land in the Sierra Nevada region have increased significantly in recent decades.

Previous studies that have investigated the connection between climate change and fires have tended to focus on monthly or yearly trends. But Gutierrez and her team were interested in the role of short-lived heat waves, which can have dramatic impacts on fire risk.

As the summer stretches on, vegetation in this area slowly loses moisture.  By September it’s “completely flammable and ready to burn,” Gutierrez says. Hotter conditions make these fuels dry out more quickly. 

“The potential to have an explosive initial fire growth is pretty high, and on those really hot days fires that start are really hard to contain,” Gutierrez says. “Usually what will burn will burn.”

One example of this danger is the Ranch Fire of 2018, which was ignited by sparks from a rancher who was hammering a metal stake into the ground, a routine activity. The hot, dry conditions allowed the fire to spread rapidly and eventually become part of the Mendocino Complex Fire.

To understand how climate change will affect fire weather, Gutierrez and her colleagues first examined NASA satellite imagery of burned land, recorded fire perimeters, and weather data for the Sierra Nevada range from 2001 to 2020. During this time there were 441 fires larger than 100 acres in the region. The team observed that more than 86 percent took place from June through September, and these summer fires covered 23 percent of the Sierra Nevada’s area.

[Related: Wildfires could hit your hometown. Here’s how to prepare.] 

Additionally, fires were much more likely to take place on hot days. The researchers calculated that a 1 degree Celsius increase in daily temperature translated into a 19 to 22 percent increase in the probability of a fire starting, and a 22 to 25 percent increase in the area burned if a fire did occur. 

Last year’s fire season left a particularly large mark on these estimates. “The 2020 fire season was so big it was off the charts, especially for the amount of burned area that occurred,” Gutierrez says. At the time, she points out, California was gripped by a major heat wave.

“It’s kind of scary to see how sensitive these fires are to small changes in temperature, and how that could really impact the overall fire season based on one day that was really hot,” Gutierrez adds.

She and her team next reconstructed past fire seasons using temperature records dating back to the 1980s. Between the 1980s and the 2010s, the amount of area that burned during the summer increased by more than three times and the average daily temperature rose by around 1.8 degrees Celsius (3.24 degrees Fahrenheit). 

The researchers estimated that warming summers increased the number of fires by about 41 percent and burned area by about 48 percent since the 1980s, accounting for about 30 percent of the overall increase in annual burned area. This indicates that other variables—such as lightning strikes and high winds—also have an important influence on fire seasons. 

Next, the team used climate models to explore how fire risk in the Sierra Nevada range might change as temperatures continue to rise. They calculated that by the 2040s, the number of fires and overall burned area will increase, respectively, by roughly 51 percent and 59 percent. 

For this analysis, the researchers focused on the relationship between hot conditions and fire activity. “There’s all these other factors that drive fires as well,” Gutierrez acknowledges. “What we show in this analysis is just the fact that temperature does have a key role.”

In the future, the findings could be used to improve forecasts for wildfire risk, she and her colleagues wrote. As a next step, the team hopes to investigate the vulnerability of other parts of California based on their fire history and predicted temperature changes.

“We could potentially expand this analysis to the whole entire state,” Gutierrez says.

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There’s been growing speculation in recent years that the community of bacteria, viruses, and other microorganisms dwelling in the gut somehow contributes to autism. However, scientists reported this week, the reality may in fact be the reverse.

“Instead it looks like characteristics of autism contribute to microbiome differences, almost turning the hype or the proposed mechanism on its head,” says Chloe Yap, an MD/PhD candidate in psychiatric genomics at the the University of Queensland and the Mater Research Institute in South Brisbane, Australia. 

Children diagnosed with autism are more likely than their peers to experience gastrointestinal complaints such as constipation, diarrhea, and abdominal pain. This has led some researchers to propose that the gut microbiome might differ in autistic people and perhaps even cause the condition.

There are studies indicating that a number of conditions, ranging from inflammatory bowel disease to rheumatoid arthritis, cardiovascular disease, and depression, are in some way influenced by the gut microbiome. However, the evidence for the microbiome causing autism, or even being different in autistic people, is pretty weak, Yap says. 

She and her colleagues examined stool samples from nearly 250 kids, and found no link between a diagnosis of autism and the composition of the microbiome. However, children with less varied diets were more likely to have less diverse microbiomes, as well as restricted or repetitive interests and sensory sensitivities, the team wrote on November 11 in the journal Cell.

“Children on the autism spectrum often prefer to eat a narrow selection of foods, and then that affects the microbiome,” Yap says. “So in other words, it’s a case of mind over microbes rather than the other way around.”

[Related: Millennium-old poop reveals the surprising diversity of our ancestors’ microbiomes]

Despite the lack of evidence supporting the gut microbiome’s contribution to autism , she says, “There’s sort of been this building momentum and hype around the autism microbiome, which has led to some so-called therapies that claim to help or support children on the spectrum by modifying the microbiome.” These include probiotics, fad diets, and fecal microbiota transplants. 

To investigate whether there was any basis for these claims, Yap and her team took stool samples from 247 children and adolescents between the ages of 2 and 17 and analyzed them for microbial DNA. The participants lived across Australia and included 99 kids who’d been diagnosed with autism, 51 of their siblings who hadn’t received a diagnosis of autism, and 97 unrelated children who also hadn’t been diagnosed with autism. The team also collected health, lifestyle, dietary, and genetic information from the children.

The researchers found no significant differences in the overall composition of the microbiomes of children with and without autism diagnoses. The team also didn’t find any connection between the microbiome and sleep problems (which are common in autistic people). 

Additionally, the team searched for 607 bacteria species and identified just one that was noticeably less abundant in stool samples from kids on the autism spectrum. 

They did, however, observe that children with more watery stools (a common sign of gastrointestinal issues) had microbiomes that were more limited in diversity. Children who ate fewer different kinds of foods also had less diverse microbiomes.

Although there wasn’t a direct link between a diagnosis of autism and the microbiome, children on the autism spectrum tend to have less diverse or poorer-quality diets according to an assessment known as the Australian Recommended Food Score.

To find out which characteristics might be driving this relationship, the researchers analyzed data on the children’s behavior and genetic differences associated with common autistic traits. “We found that measures of restricted interests and sensory sensitivity, both of which are core diagnostic domains of autism, were associated with [having a] restricted diet,” Yap says. Having a less varied diet would in turn lead to a less diverse microbiome and gastrointestinal problems, she says.

The findings suggest that “treatments” for autism that target the microbiome aren’t based on solid evidence. However, Yap says, the findings do highlight the importance of helping kids on the autism spectrum have healthy, balanced diets. “Having a good diet is really important for long-term wellbeing and development, so that’s something to really start looking into,” she says.

Still, the researchers say, it will be important to verify the findings by examining larger groups of participants from around the world. “We’re aiming to progress this as a team, but hope that others in the field do similar analyses,” Jacob Gratten, the leader of the Mater Research Institute’s Cognitive Health Genomics group and another coauthor of the findings, told Popular Science in an email. The team also plans to follow children over time to see if variations in the gut microbiome in infancy are related to later autism diagnosis.

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To cope with the threat of marauding hornets, honeybees in Vietnam have developed a distinct, siren-like noise that serves to marshal the hive’s defenses, scientists reported this week. 

Scientists recorded honeybee hives during times of peace and in the midst of hornet attacks, and discovered that the arrival of the winged predators triggered a cacophony of noise and activity. Particularly striking was a harsh sound that changed pitch quickly and unpredictably—qualities also heard in the alarm shrieks, fear screams, and panic calls of mammals and birds. At the same time, worker bees began assembling at the entrance of the nest to repel the invaders.

Across the animal kingdom, abrupt sounds that change dramatically in frequency are used as alarm calls because they’re so hard to ignore, says Heather Mattila, an entomologist at Wellesley College, who published the findings on November 9 in the journal Royal Society Open Science. 

“You never get used to them; they always grab your attention because they sound a little bit different every time,” she says. “It’s really interesting to see that the ways bees do this share a lot of the same traits with the ways mammals do it too, including ourselves.”

The Asian honeybees that she and her colleagues observed are more petite and live in smaller groups than the European honeybees commonly kept for their nectar. “They’re small and quick, and that’s because in Asia they face these really numerous hornet predators,” Mattila says. These include Asian hornets (Vespa velutina), which are solitary hunters that hover in front of nests to pick off individual bees.

The deadliest threat, however, comes from the giant hornet species known as Vespa soror, which resembles its close relative the so-called murder hornet (Vespa mandarinia). These insects attack in groups capable of decimating entire honeybee colonies. 

It all starts when a hornet scout finds a beehive and returns with reinforcements. After slaughtering the defending bees, the hornets take over the nest and feed any eggs and larvae they find inside to their own hungry offspring. “It’s kind of a brutal scene, because these giant hornets are really focused on finding a lot of food quickly and honeybees are a great target for that,” Mattila says.

But honeybees have a few tricks to help them fight back. When an Asian hornet approaches, the bees gather outside in a group and shake their abdomens back and forth, apparently to let the hornet know it’s been spotted and can’t sneak up on them. 

[Related: Murder hornets are officially here, but don’t freak out yet]

Unfortunately, this move doesn’t work on giant hornets. “They’re not afraid of bees,” Mattila says. “They’re much larger, they’re heavily armored.” They do seem to have an aversion to animal dung, though, which the bees smear around their nest entrances as a deterrent. 

Another nifty home security system  is known as bee balling. This tactic involves hundreds of bees working together to engulf an unlucky hornet, causing it to simultaneously overheat and suffocate. 

Mattila and her colleagues were studying these defenses in Vietnam’s Hanoi Province when they noticed that the honeybees also made quite a racket whenever giant hornets struck. “You could stand a couple feet away from a hive and hear the sounds the bees were making,” she says. “The bees sounded very upset, very distressed and agitated.” 

The researchers decided to record the insects with microphones and video cameras under several different scenarios. These included times when hornets were absent, during the course of genuine Asian hornet and giant hornet attacks, and experimental sessions in which the team presented the bees with the scent of pheromones giant hornet scouts use to mark nests for destruction. 

Even when the honeybees weren’t being harassed by hornets, the researchers noted, the hive was a bustling place. The bees used a variety of signals to communicate with each other, including several kinds of sounds made by vibrating the wings and thorax very quickly. This technique, known as piping, produces vibrations that the bees perceive through sensors in their legs. “Rather than hearing it with their ears like we would, they would feel it with their legs,” Mattila says.

The bees became noisier and signaled more frequently during skirmishes with Asian hornets and when the scent of giant hornets was present. However, during actual giant hornet assaults, the hive became downright frenzied and “got extremely loud,” Mattila says. When listening to an audio recording of the hive, she says, she could always tell when a giant hornet had shown up. “The bees would just go nuts.” 

Part of the reason for this, she and her team realized, was that the giant hornets provoked a kind of piping from the bees that hadn’t been documented before, which the researchers referred to as antipredator pipes. “They make them in rapid series, and so it sounds like a siren that’s going on and on and repeating,” Mattila says. “They change a lot in tone; they’re really harsh and noisy.”

While piping, the honeybees also raced about, buzzed their wings, and raised their abdomens to reveal a pheromone-producing gland. This could mean they were warning the hive of danger through multiple senses.

“Our hypothesis is that the sound is like, ‘the hornets are here,’ and the smell is like, ‘everyone come and gather at the entrance to start defending,’” Mattila says. “At this point we know that these things are linked: the hornet shows up, the bees make the sound, and also, at the same time, a lot of bees start showing up outside the colony and getting ready for defense.”

Although the antipredator pipe does seem to be a rallying call, more research is needed to determine what exactly the signals mean and whether they prompt a particular defense. It also remains to be seen whether other bee species use antipredator pipes, and whether the Asian honeybees make these signals when faced with other predators.

“We don’t know if it’s the giant hornets—the fact that they’re this particular species—or just that they’re big, or that they get right up to the entrance,” Mattila says. “But something about how they attack makes the bees inside produce this really urgent sound.”

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The COVID-19 pandemic caused a surge in demand for disposable plastics that has resulted in more than 25,000 tons of litter flowing into the world’s oceans, scientists in the United States and China reported on Monday.  

The researchers estimated the amount of plastic waste generated by different countries, calculated how much was ferried to the sea by major rivers, and used computer models to simulate its journey through the global ocean. They found that the pandemic spawned more than 8 million tons of plastic debris from hospitals, personal protective equipment, and online shopping, and most of the waste that reaches the ocean will wind up in beaches and coastal sediments.

“This poses a long-lasting problem for the ocean environment,” the team, which included researchers from Nanjing University and the University of California San Diego’s Scripps Institution of Oceanography, wrote in Proceedings of the National Academy of Sciences. “We call for better medical waste management in pandemic epicenters, especially in developing countries.”

The emergence of COVID-19 represents the most severe pandemic yet to occur in an era of plastics and disposable items, noted João Canning Clode, a marine ecologist at Portugal’s Marine and Environmental Sciences Centre and the Smithsonian Environmental Research Center in Maryland, who has written about the potential ways that the COVID-19 pandemic could exacerbate marine pollution.

As cases climbed, reaching 212 million people worldwide by August 23, 2021, so did the amount of medical waste that contained plastic. This included COVID-19 testing kits and personal protective equipment such as face masks, gloves, and face shields. Single-use items such as plastic cutlery were also used to minimize the risk of spreading the novel coronavirus, particularly before vaccines became available, Canning Clode told Popular Science in an email. 

Meanwhile, people turned to online shopping at an “unprecedented speed,” the researchers wrote. The material used to package these orders became another source of excess plastic. 

Not all of this plastic is processed properly or recycled, and some of the mismanaged waste will eventually find its way to rivers and the ocean. According to one estimate, about 1.56 billion face masks entered the seas in 2020. All this debris poses a number of threats to marine animals, which may eat or become entangled within the plastic. 

To find out how much plastic waste has been created because of COVID-19, the researchers considered a variety of data sources, such as statistics on population, mask production, and COVID-19 infections, tests, and hospitalizations, as well as financial reports from Amazon, Walmart, and other top e-commerce companies.    

[Related: How long will we keep wearing masks?]

As of late August 2021, they estimated, 193 countries had generated about 8.4 million tons of pandemic-related plastic waste. Hospitals contributed an estimated 87.4 percent of the trash, while personal protective equipment used by the general public accounted for 7.6 percent, and online shopping and COVID-19 test kits contributed, respectively, only 4.7 percent and 0.3 percent.

A whopping 47.6 percent of confirmed COVID-19 cases have occurred in the Americas, followed by 31.22 percent in Asia and 17.26 percent in Europe. However, the continent that contributed the most plastic waste was Asia (an estimated 46 percent), followed by Europe (24 percent) and North and South America (22 percent). 

While online shopping—and, on the bright side, mask wearing—were more prevalent in Asian countries, the study authors note that flawed existing systems for dealing with medical trash likely accounted for most of the gap. “The biggest sources of excess waste were hospitals in areas already struggling with waste management before the pandemic; they just weren’t set up to handle a situation where you have more waste,” Amina Schartup, an assistant professor at Scripps Oceanography, said in a statement. 

The team next investigated how much of this excess plastic would enter and be carried out to sea by 369 major rivers and their watersheds, based on the speed and other characteristics of the rivers. They calculated that about 25,900 tons of plastic would reach the oceans, representing around 1.5 percent of the total plastic waste discharged by rivers worldwide. The top debris contributors were the Shatt al Arab, Indus, Yangtze River, and Ganges Brahmaputra in Asia, followed by the Danube in Europe, and the Amur in Asia, highlighting hotspots that will require “special attention in plastic waste management,” the researchers wrote.

Finally, the team used a computer model to simulate how this litter will move through the oceans, taking into account how seawater circulates and how several different kinds of plastic might become fragmented or otherwise altered during their travels. They found that most of the plastic waste will land on beaches and seabeds within three years. However, the Arctic Ocean will likely become a dead-end for some of it.

“The Arctic ecosystem is considered to be particularly vulnerable due to the harsh environment and high sensitivity to climate change, which makes the potential ecological impact of exposure to the projected accumulated Arctic plastics of special concern,” the researchers concluded.

While several highly effective COVID-19 vaccines are available in the United States and abroad, the pandemic isn’t quashed yet. By the end of 2021, the researchers estimate, a total of 11 million tons of excess plastic will have been generated, and rivers will have carried 34,000 tons of this waste to the sea. 

It’s worth remembering, of course, that the excess waste generated because of the pandemic makes up just a small fraction of a much larger plastic problem. “The ongoing assembly of trash, plastics and debris in the ocean is severely affecting marine life, and today marine litter is considered as one of the most relevant pollution problems the planet is experiencing,” Canning Clode said. 

To quash plastic waste, the researchers say, it will be important to improve plastic waste collection, treatment, and recycling technology; develop more eco-friendly alternatives; and raise awareness among the general public about the environmental impacts of personal protective equipment and other plastic products.

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The subterranean fungi known as truffles are best known as human delicacy, often sniffed out with the help of trained pigs or dogs. But it turns out these shrooms are popular outside the mammalian world, too: two common birds in Patagonia are truffle hounds in their own right, according to a new study in Current Biology. 

The researchers identified a plethora of fungal DNA in the South American birds’ feces, and found that the spores were likely still viable—in other words, the avian gourmands may help the truffles proliferate. The researchers also noticed that some of the brightly-colored fungi closely resembled local berries, perhaps as a strategy to catch the birds’ interest. 

“These are really, really common birds that are really widespread over almost the entire area where you find these southern beech forests—and yet nobody has noticed this interaction before,” says study co-author Matthew E. Smith, a mycologist at the University of Florida and curator of the fungal herbarium at the Florida Museum of Natural History. “That suggests that people should be looking at birds as dispersal agents of fungi in other systems.”  

Unlike mushrooms that sprout from the ground and shoot their spores into the air, some fungi form enclosed structures called truffles that sit under the leaf litter or in the top inch or two of soil. “The’re basically in a packet [with] a rind around the outside,” Smith says. “Those fruiting bodies are just jam-packed full with spores, and we think the main way they get around is by animals eating them.”

[Related: This fungus has over 23,000 sexes and no qualms about it]

As the spores mature, many truffles emit strong odors that attract hungry mammals. The fungi often form symbiotic relationships with tree roots, exchanging nutrients they’ve extracted from organic matter in the soil for sugars produced by the plants.

These relationships are important for the southern beech trees that dominate Patagonia’s forests. However, the sorts of ground-dwelling mammals that would typically spread truffle spores around are sparse. More common are several birds that forage on the ground, including the black-throated huet-huet and chucao tapaculo. These critters aren’t too picky about what they eat; they’ve been documented feasting on worms, slugs, and other invertebrates as well as fruits and seeds, Smith says.

While hunting for truffles for a research project on fungal diversity, Smith and his colleagues started to witness some unexpected behavior. After the researchers finished raking through the leaf litter and moved on, the birds would approach and poke through the disturbed area. One intrepid bird followed Smith around for hours. “It was interested in what I was finding in the soil,” he says. “That was weird; I had never seen anything like that before.”

Smith and his team also realized that several purple and white fruits at these sites looked so much like local truffle species that it was difficult to tell them apart. They suspected that this was no coincidence. Birds often rely on vision rather than their sense of smell to find food; a berry-like appearance could give the truffles a better shot at being consumed. 

What’s more, the researchers found what seemed to be the remains of a few fungal feasts. “We sometimes would find truffles with big peck marks in them,” Smith says. “It looked like a chicken had come along and plunged its beak into the truffle several times.”

He and his colleagues decided to investigate. They collected more than 100 fecal samples from across 700 kilometers (435 miles) in Chilean Patagonia—in some cases holding the birds in cloth bags until they pooped—and tested them for fungal DNA. Among the wealth of genetic material were 45 truffle species, including several that haven’t yet been properly described and named. 

The researchers also observed that both the black-throated huet-huet and the chucao tapaculo had fungal communities in their feces that differed from those found in the soil where they’d relieved themselves. This supports the idea that the birds help the fungi they eat disperse into new places. 

Smith and his team then examined the poop samples under a microscope to get a closer look at the truffle spores within. About 50 percent of the spores were intact after their journey through the birds’ digestive tracts, suggesting that they were still alive and could sprout anew elsewhere.

“Basically everywhere we went where we could find the birds, we found evidence that they were eating fungi,” Smith says. One member of the team even witnessed a chucao tapaculo gobbling up a truffle.  

Scientists have often assumed that birds mostly turn to fungi only if their preferred meals aren’t available, Smith says. However, the new findings suggest that, at least for these two Patagonian species, truffles regularly make it onto the menu. 

“We don’t know how much this applies to other places until people look,” Smith says. “It could be that Patagonia is quite unique in this way.” However, he says, it’s more likely that birds play an important role in spreading fungal spores in other habitats around the world. 

“The first place I’d look is other birds that are on the ground eating all sorts of things,” Smith says. “They’re probably eating truffles in those systems too and it just hasn’t been observed.”

The researchers next plan to explore how much nutritional value different truffle species offer the birds, and whether they actually prefer the fungi over grubs and other common foods. 

Bird populations in Patagonia are increasingly threatened by the fragmentation of their forest habitats, Smith and his team noted in the paper. Understanding the connections between birds, fungi, and trees will be vital for future conservation efforts, he says.

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A fossilized skull discovered in Ethiopia in the 1970s should be considered an entirely new species of human, scientists proposed this week in an effort to shed light on the very murky question of what to call our ancient ancestors. 

In a study published on Thursday in Evolutionary Anthropology Issues News and Reviews, researchers compared anatomical traits in fossil hominins—the group that includes present-day humans and our extinct close relatives—from Africa, Europe, and Asia. They concluded that two currently recognized species should be retired, and that the 600,000-year-old remains from Ethiopia, along with several other specimens, should be classified as a new species they’ve dubbed Homo bodoensis.

Not everyone is convinced that a new species name is needed—after all, none of these specimens represent lineages that have never been studied before. However, the researchers argue, the changes could help researchers decipher a murky period in human evolution and move past terms with vague meanings and racist legacies. 

[Related: Your ancestors might have been Martians]

“We’re becoming increasingly aware that these groups did move and did interact, and that’s why it’s important to have a proper way of talking about them,” says Mirjana Roksandic, a paleoanthropologist at the University of Winnipeg in Manitoba and coauthor of the paper. “​​It really opens the possibility to talk about who moved when, and what happened to them when they moved, and who actually interacted with whom.”

She and her colleagues focused on hominins who lived during the Middle Pleistocene age, which spanned from 774,000 to 129,000 years ago. Although paleoanthropologists refer to these hominins as different species, they’re not using the term as most of us normally think of it. “They interacted, they interbred, and they cannot be considered as definite biological species,” Roksandic explains. Instead, the category is used to describe groups of hominins with very similar anatomical features.

These differences are more obvious in some groups of hominins than others. European Neanderthal fossils from this period differ in numerous ways from modern humans, Roksandic says. However, many other hominin fossils look very similar, making it harder to determine how they relate to each other and to Homo sapiens.

In the past, new species were often declared on the basis of a few teeth or other fragmentary evidence, says John Hawks, an anthropologist at the University of Wisconsin-Madison who was not involved in the new research. One such case was Homo heidelbergensis, which was first named after a jawbone found in a gravel pit in Germany in the early 20th century, he says. 

Then, in later decades, many fossils that didn’t seem to fit with Neanderthals, modern humans, or our ancestor Homo erectus were lumped in with Homo heidelbergensis. “The species was named after a mandible; we never knew what the head and face should look like,” says Shara Bailey, a biological anthropologist and director of the Center for the Study of Human Origins at New York University. “Basically it’s like a trash basket category.”

This helped spawn a “totally confusing” situation, Roksandic says, in which the name Homo heidelbergensis is sometimes used to refer generally to hominins from the Middle Pleistocene, and other times to refer to various specimens found in Europe. She and her colleagues argue that it’s time to abandon the name altogether, given that recent genetic evidence suggests that many fossils currently assigned to Homo heidelbergensis are actually early Neanderthals. 

Then there’s Homo rhodesiensis, which was first known from a skull uncovered by mining activity in Zambia in the 1920s. The term is sometimes used to indicate a common ancestor of Homo sapiens and Neanderthals, but can also refer to all the hominin lineages represented in the Late Pleistocene. But the name is rarely used in either context, because of its association with the atrocities committed under British colonial rule in the region of Rhodesia (now Zambia and Zimbabwe). For these reasons, Roksandic’s team writes in the new study, Homo rhodesiensis has to go. 

[Related: Humans owe our evolutionary success to friendship

“Homo bodoensis would fill that void that’s left by Homo rhodesiensis,” she says. The researchers selected the enigmatic skull from Ethiopia to represent the species in their description. However, they also consider the Zambian skull and several other sets of fossils from Africa, and possibly the eastern Mediterranean, as members of Homo bodoensis. 

Like Neanderthals and some Asian hominins from the Middle Pleistocene, Homo bodoensis seems to have had an enlarged brain—a crucial development on the road to modern humans. It’s likely that Homo bodoensis was the first to split off from their shared common ancestor, with the remaining branch later splintering into Neanderthals and a group called Denisovans found in Asia, the researchers propose. 

Homo bodoensis’s most distinctive feature is a three-part segmented brow ridge. There’s no obvious advantage to having different kinds of brow shapes, but this region does vary among different kinds of hominins, Roksandic says. Neanderthals had thick, curved brow ridges, while in modern humans the brow is less pronounced and the sides are thinned out. 

As a next step, she and her colleagues are planning to investigate whether fossils from Europe and Asia might be members of Homo bodoensis, which could shed light on whether and when the group might have moved out of Africa.

“It’s really hard to understand what is happening in terms of human evolution in that time period unless you look at it on a very global scale,” Roksandic says. 

What’s in a name?

Hawks agrees that the two species that Roksandic and her colleagues propose jettisoning are “a problem.”

“These are confusing names, they have bad histories, and it would be way better if we had names that actually could be [scientifically] tested and that can apply in a sense that all of us are willing to use,” he says.

However, he favors a different solution. “All of these populations interbred with each other, and it seems like they’re the same species—and the name for that species is Homo sapiens,” Hawks says. “Why don’t we recognize that they’re the same species, and all these fossils going back to the common ancestor are representatives of that evolving species?”

Bailey also isn’t sure that Homo bodoensis brings clarity to this phase of human evolution. Given that the fossils seem to belong to a direct ancestor to Homo sapiens, she says, “Why don’t we just call that archaic Homo sapiens?” 

Nonetheless, Bailey says, the paper makes a good case for ditching Homo heidelbergensis and Homo rhodesiensis. “It also provides readers with kind of a glimpse into just how complex human evolution is, that it’s not this ladder-like [process in which] we evolved step-by-step into ‘Tada, we’re Homo sapiens!’”

The names we give bygone hominins reveal how we see them fitting into our family tree—and what makes the humans alive today unique. “That’s what people care about: what’s ‘us,’ when did we evolve, when did we develop the things we associate as being special about us?” Bailey says. 

Names allow us to understand the relationships between different hominin lineages and how they interacted, Hawks says, but they needn’t be set in stone. 

“It’s good to have these conversations,” he says. “Looking at the way that we describe groups, it’s really important to continue to have critical thinking about what are we accomplishing by naming them?”

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Climate change is worsening many kinds of natural disasters and dangers around the globe, from fires to hurricanes. But there’s one kind of danger that might actually lessen as temperatures heat up, according to an analysis of European avalanches that spans more than two centuries.

Scientists examined climate records and historical documents describing more than 730 avalanches since the 1780s in France’s Vosges Mountains. They saw that when winter temperatures rose in the mid 19th to early 20th centuries, the number and size of avalanches plummeted, and those that did occur seemed to shift upslope. 

The findings could have implications for efforts to understand how climate change will affect such hazards in years to come. “If you look back in the past at what happened in such low elevations, you will be able to anticipate what’s going to happen in the future at high elevations,” says Nicolas Eckert, a statistician at the National Research Institute for Agriculture, Food and Environment and Grenoble Alpes University in France. He and his colleagues reported the findings on October 25 in Proceedings of the National Academy of Sciences.

The amount, density, and other physical properties of snow in an area all affect the risk of avalanche. “This means that, in theory, snow avalanches should be very sensitive to climate change,” Eckert says. But until now, he adds, there hadn’t been much investigation into that connection. 

Records of past avalanches are often sparse and don’t reach far back enough into the past for long-term trends to become apparent. The Vosges Mountains, a small range in northeast France, are one exception. People have inhabited the area, from its valley floors to the mountain ridges, for centuries.

Eckert and his colleagues were able to gather a wealth of historical documents that referenced 734 avalanches that took place between 1783 and 2013. These included photographs, diaries, administrative documents, postcards, travel guides, and more. Among them were a hand-drawn map from the mid 19th century showing the location of a house damaged by an avalanche, a photo of the aftermath of an avalanche that reached a valley in 1894, and a document that mentioned a man who “died under the ruins of his house that a torrent of snow that rushed from the top of the gully has overthrown from top to bottom” in 1783. 

[Related: What to do if you get caught in an avalanche]

The researchers also examined temperature and precipitation records and historical documents that described winter conditions in the region. They then analyzed how both avalanche activity and climate conditions have changed over time.

Initially, their study reports, avalanches were “intense and widespread” across all elevations. But that changed during the period from around 1850 to 1920, when the Little Ice Age (a chilly period that affected Europe and North America from the 14th to 19th centuries) drew to a close. As winter temperatures warmed by about 1.35 degrees Celsius (2.43 degrees Fahrenheit), the area saw seven times fewer avalanches per year. At the same time, such events also shrank in size and occurred over a shorter season. 

Perhaps most strikingly, avalanches almost completely vanished from low-elevation sites, and today only persist in the highest zones of the Vosges Mountains. “That all directly comes from the fact that climate has warmed between the mid 19^th century and beginning of the 20^th century,” Eckert says.

When temperatures rise, snow becomes scarcer. Other characteristics of the remaining cover, including how cold the snow is and how it is layered, may also change in ways that affect avalanche activity. 

Today, our climate is heating up due to the use of fossil fuels, and scientists expect snowfall to diminish in many places. This could mean that the risk of avalanches decreases as well, Eckert says. “However, of course we know that there is lots of variability,” he adds, pointing out that warming temperatures are currently driving more intense snowfall and avalanches at very high elevations in the Alps and Himalayas. “So snow avalanches are going to persist in many areas as well, even if they’re decreasing at the lowest altitudes.”

Still, his team’s analysis suggests that avalanche activity at lower elevations may be a preview of what’s in store for higher-elevation terrain. As a next step, he and his colleagues will investigate whether similar patterns may play out in other ranges beyond the Vosges Mountains. They’re also working on predictions for how changes in avalanche activity could translate into changes in the risk to people.

“We can readily compute risk for buildings or people inside buildings, but when it comes to risk for people doing backcountry activities it’s more complicated because they go where they want to go,” Eckert says. “The correlation between a decrease in avalanche activity and a real decrease in risk is not that obvious.”

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From 1977 to 1992, the southeastern African country of Mozambique was gripped by a civil war during which both sides financed their efforts by hunting African savanna elephants for their ivory. This intense poaching slashed the elephant population of Gorongosa National Park by 90 percent. 

It also had another unintended impact on the animals, scientists reported this week. Female elephants without any tusks became much more common after the conflict. When the researchers examined population records and genetic material from park-dwelling elephants, they found that this trait rose swiftly as a response to poaching, and they pinned down several genes that may cause it. 

“This study highlights the ubiquity of human influence across the tree of life,” says Shane Campbell-Staton, an evolutionary biologist at Princeton University, who published the findings on October 21 in Science. “Even the largest organisms on the planet are not just being affected by population decline…we’re literally changing the trajectory of their evolution moving forward.”

There are numerous cases of animals evolving in response to human activities, from moths darkening amidst the smog of the Industrial Revolution to lizards upping their heat tolerance to survive in sweltering cities and insects becoming resistant to pesticides. “Most of what we know comes from relatively small animals that are very abundant and have very quick generation times,” Campbell-Staton says. These changes are harder to track in large, long-lived animals that reproduce slowly, such as elephants.

[Related: Elephants can add a cuddly new cousin to their family tree]

After the Mozambican Civil War ended, people began to notice that tuskless elephants had become more common in Gorongosa National Park. However, Campbell-Staton realized, little was known about what genetic changes might have actually caused the phenomenon. 

To get to the bottom of this mystery, he and his team pored over photos and videos of elephants in the park from before the conflict, as well as more recent observations. Generally, it’s rare for elephants to be born without the ability to develop tusks, and the trait is only seen in females. The park’s elephant population already had an unusually high number of tuskless females before the war, perhaps as a consequence of past hunting practices. Afterwards, though, the proportion of females without tusks had nearly tripled to 50.9 percent. 

“The question is whether or not this is actually natural selection favoring tuskless females, or whether or not it’s just because of the entire population decline that you get this rise simply by chance,” Campbell-Staton says. 

He and his colleagues ran computer simulations of the waning population from 1972 to 2000. They concluded that the odds of winding up with a population in which half the females were missing tusks were very slim, unless this characteristic was giving the elephants a survival advantage. 

The researchers suspected that the mutations responsible for tusklessness would be dominant—meaning that only one copy of the abnormal genes would be needed to result in a lack of tusks—in female elephants, and lethal for males. Supporting this idea, they observed that tusked mother elephants didn’t have tuskless daughters. 

On the other hand, tuskless elephants should have one abnormal copy of the gene inherited from their own mothers, and one normal copy inherited from their fathers. This means that a tuskless mother has a 50 percent chance of passing the trait to her offspring. Sure enough, the researchers found that elephants born to tuskless mothers were more likely to be female (the gene is deadly in males), and about half of these daughters were tuskless.

Campbell-Staton and his team next searched for differences in the genomes of tusked versus tuskless elephants. They identified two genes related to tooth development that might have contributed to the rise of tuskless females. One, called MEP1a, plays a role in forming dentin, the layer of tissue surrounding the tooth’s pulp. 

The other is known as AMELX and is involved in enamel production. In humans, abnormalities in this gene and several of its close neighbors collectively cause a syndrome that’s lethal to males and can prevent the maxillary lateral incisors, which correspond roughly to elephant tusks, from growing in females. 

The precise nature of the genetic underpinnings of tusklessness in the park’s female elephants have yet to be determined, Campbell-Staton says. Another open question is whether the same thing could happen in other elephant species that are also threatened by poaching, adds John Poulsen, an ecologist at Duke University who studies how African forest elephants are affected by human disturbances and was not involved with the new research. Still, he says, finding such quick evolution in the elephants of Mozambique “is remarkable.”

“When I first read the paper, my first thought was, ‘Wow this inspires hope for biodiversity conservation; maybe species like the elephant that are really slow-reproducing can actually adapt quickly to human pressures,” Poulsen says. However, the evidence that males cannot develop this trait is troubling, particularly since male elephants are already targeted more by poachers because of their larger tusks. It’s possible that the abundance of tuskless females could focus more poaching pressure on male elephants.

“That puts us in a real pickle,” Poulsen says. “It also means that we can’t sort of depend on evolution to get us out of this problem of unsustainable killing of elephants…we still need management and we still need policy efforts to try to conserve elephants.”

The evolution of tusklessness among elephants may also have far-reaching consequences for other species. Tusks are a bit like a Swiss army knife for elephants, Campbell-Staton says. Elephants use their tusks for a variety of tasks, including stripping bark off of trees and digging for subterranean minerals and water sources. These activities can open up habitat for other animals, destroy trees, and allow other plant species to grow—and have a myriad of other complex ecological effects.  

“If elephants don’t have this key tool to provide these important services, then what happens to the rest of the ecosystem?” Campbell-Staton says. 

In recent years, the elephant population of Gorongosa National Park has grown and the prevalence of tusklessness has begun to drop. Still, the animals grow slowly and take nearly two years to gestate their young. The elephants may have evolved quickly in response to poaching, Campbell-Staton says, but it will take them much longer to rebuild their numbers and play the same role in the ecosystem as they did before the war.

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As restrictions on international travel have lifted over the past few months, visitors to the US who were immunized abroad started “doubling up” with another COVID-19 vaccine by a different manufacturer. Some were hoping for more powerful protection from the highly contagious delta variant of the novel coronavirus. Others have moved for work or school and worry about meeting requirements for FDA-approved vaccines. 

A few Americans sought out additional doses of the vaccine as well, including ones produced by different manufacturers. And outside the U.S., a handful of countries are moving ahead with second or third doses by different COVID-19 vaccine developers. Now, the FDA has announced that in addition to authorizing booster shots of both the Moderna and Johnson & Johnson vaccines (boosters for Pfizer’s vaccine were authorized last month), the regulatory agency says its now okay to mix and max what booster you get.

Beyond adding a booster for better overall protection against COVID-19, there might be other compelling reasons to mix and match COVID-19 shots, according to some experts. With its authorization this week, which endorsed a mix and max method, the FDA cited a study funded by the National Institutes of Health, which found that mixing and matching was safe and might offer better protection. Scientists are currently exploring how the immune response differs in people who receive one versus two types of immunization. However, the practice could help stretch limited vaccine supplies and may under some circumstances offer superior immune protection.

“The reality is, when you have got so many people vaccinated with half a dozen different types of vaccines out there, the mixing and matching…is probably going to happen,” says Deborah Fuller, a vaccinologist at the University of Washington School of Medicine in Seattle. “It’s probably going to be okay, and it may even be an advantage to see these vaccines actually mixed.”

Have vaccines been mixed and matched before? 

Yes, although not always by design. 

People sometimes receive doses of both the injectable and oral versions of the polio vaccine, which respectively contain “killed” and weakened versions of the virus, Fuller says. In the United States, it’s also common for people to get different versions of the seasonal flu vaccine from one year to the next. 

Deliberately combining different vaccines developed for the same disease is a hot area of research, says ​​​​Kirsten E. Lyke, director of the Malaria Vaccine and Challenge Unit at the University of Maryland School of Medicine’s Center for Vaccine Development and Global Health in Baltimore. 

“It is a tried-and-true approach that we do with vaccine testing all the time, but it hasn’t gotten to primetime, where there is a licensed vaccine combination that intentionally has a mixed platform,” says Lyke, who recently coauthored an editorial in Nature Medicine about mixing COVID-19 vaccines.

Scientists who study vaccines and immunology have previously investigated the technique—which goes by the technical term heterologous prime-boost—for ebola, tuberculosis, and other infectious diseases. Many teams of researchers, including Fuller and her colleagues, have been studying the effects of intentionally mixing different kinds of HIV vaccine candidates for decades. One pairing, not studied by Fuller’s team, lowered the rate of infection by 31 percent in clinical trials. Scientists viewed even this modest degree of protection against such a wily virus as an important milestone. 

So far, Fuller says, previous studies on combining vaccines developed for other infectious diseases haven’t uncovered any safety issues. Still, more research is needed to confirm that this holds true for COVID-19 vaccines. 

[Related: 4 important question about COVID booster shots, answered]

What happens in the immune system when you mix vaccines for the same disease? 

The COVID-19 vaccines currently in use rely upon a variety of strategies to rouse the immune system. 

Those developed by Moderna and by Pfizer and BioNTech are mRNA vaccines, which include snippets of genetic material that code for the spike-shaped protein on the surface of SARS-CoV-2. Others, including the shots developed by Johnson & Johnson and by the University of Oxford and AstraZeneca, are known as viral vector vaccines. In these shots, a different sort of virus is genetically engineered to ferry the coronavirus genes. Still others in use outside the U.S. contain bits of spike protein or inactivated versions of the virus. 

A pairing of two different types of vaccines will probably be more effective than a combination of two different vaccines that use the same basic strategy, Fuller says. “We think that…some are just better at triggering certain arms of the immune system than others,” she says. “And when you have them in combination, they start to synergize and leverage all of our defenses.” 

For example, adenoviruses—the kind of delivery virus, or “vector,” found in the Johnson & Johnson and AstraZeneca shots—seem to be particularly good at rousing T cells, which are white blood cells that play various roles, including destroying infected cells and coordinating the immune response. Meanwhile, the mRNA vaccines are especially adept at prompting the production of antibodies that target the virus, Lyke says.

“If you mixed the two, could you get the best of both vaccines and get a really great antibody response coupled with a really strong T cell response?” she says. “And then, how would that affect the vaccine efficacy?”

It’s possible that this approach would be particularly beneficial for immunocompromised people. “We do know that a third boost of an mRNA vaccine does seem to pick up a big percentage of people who didn’t respond the first time around,” Lyke says. “But it’s an interesting question as to whether giving them a Johnson & Johnson dose would be an even better immune trigger.”

There’s also another reason why mixed dosing may be advantageous, Fuller says. After a person receives a viral vector vaccine, such as Johnson & Johnson’s COVID vaccine, their body starts making antibodies not just against the coronavirus spike protein but also against the virus that is carrying that coronavirus material, known as the vector. 

“If you keep trying to boost…eventually people will build up immunity against the vector, and that vaccine’s not going to work so well,” Fuller says. “An mRNA vaccine doesn’t build that preexisting immunity and allows you to continue to get updated booster immunizations if necessary to combat the emergence of new variants.” 

Another kind of mixing may occur in people who caught COVID-19 before getting vaccinated. Several studies indicate that the shots can bolster the immune response in survivors, who already have some level of immunity from their encounter with the virus, and perhaps even offer a particularly potent kind of “hybrid immunity,” Shane Crotty, a researcher at the La Jolla Institute for Immunology in California, wrote in the journal Science in June.

Lyke and her colleagues hope to provide some answers about the safety of mixing COVID-19 vaccines and how the practice affects the immune system. They’re collaborating with the National Institutes of Health to investigate what happens when people who were immunized with one of the three vaccines under emergency authorization in the United States receive booster shots from a different manufacturer. 

“We’ll hopefully have some data by the very end of August or early September,” she says. However, she cautions, their study won’t be able to include nearly as many participants as were enrolled in the original clinical trials. “We’re not going to be able to say on a population level ‘this combination gives you 97 percent protection.’”

[Related: Everything you need to know about kids and COVID as schools reopen]

What do we know now about mixing COVID-19 vaccines?

In March, some European countries halted use of AstraZeneca’s vaccine after it was linked to rare cases of a blood-clotting condition. This meant that many people who’d received their first dose were offered second shots by other manufacturers, spurring interest in the effects of mixing and matching. 

A number of reports have offered encouraging results in recent months. People who receive the Pfizer shot after a first dose of AstraZeneca’s vaccine produce more antibodies than those given a single shot of the AstraZeneca vaccine, scientists from Spain’s CombiVacS trial reported in May.

Results from the United Kingdom’s Com-COV study suggest that mixing the AstraZeneca and Pfizer shots may prompt a stronger immune response than two doses of the AstraZeneca vaccine. Additionally, researchers found that participants who received two doses of the Pfizer vaccine produced the highest level of antibodies, while those who received a dose of AstraZeneca vaccine followed by one from Pfizer produced the most robust T cell response. But it’s still currently unclear what will yield the best effectiveness. Researchers from Germany have seen similar effects when they combined the AstraZeneca vaccine with those from Pfizer or Moderna. 

This spring the Moderna and investigational protein-based Novavax vaccine were added to the Com-COV study. Meanwhile, researchers in the Philippines are tracking the effects of combining CoronaVac, a vaccine developed in China that uses an inactivated form of the SARS-CoV-2 virus, with six other vaccines. Also under investigation is the pairing of the single-dose version of Russia’s Sputnik V (which was originally designed to use a different adenovirus vector for its first and second doses) with the AstraZeneca vaccine.

So far these small studies haven’t found any serious side effects associated with mixing vaccines, although researchers in the Com-COV study did note increased symptoms such as chills and headaches in people who received different vaccines.

Are any other countries besides the US giving mixed-vaccine regimens? 

A number of other countries are considering or have decided to mix and match COVID-19 vaccines, in addition to the United States, where the FDA recently announced that those eligible for a booster shot could get any of the three vaccines currently available. 

Several countries are using vaccines created by different manufacturers for the first and second shots in their regimens, including Denmark, Italy, Canada, Vietnam, and South Korea. Others are offering an extra dose of Pfizer or Moderna’s vaccine to people who were already fully immunized with other options. Among these are Cambodia, Germany, Turkey, and Indonesia.

“Around the world there’s a huge problem with scarcity; we absolutely need to do better if we’re going to close those pockets where COVID is able to get in and then continue replicating and forming these really severe variants,” Lyke says. “So if we can stretch the vaccine that we have available in any way, or optimize the best way to give a booster, that’s really good information to have.”

The vaccines currently available in the U.S. are very effective in preventing people from becoming seriously ill or dying from the delta variant of COVID-19.  However, it might turn out that combining COVID-19 vaccines will be “the way to go to stimulate longer-term immunity to combat even future variants to come,” Fuller says.

In the meantime, though, a more pressing concern is reaching people who haven’t yet been vaccinated. 

“We can talk about boosters ‘til we’re blue in the face,” says Lyke. “But if half the country won’t even get their primary vaccine, we really need to do better in messaging and convincing people how safe it is.” 

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During the early Jurassic Period, some 200 million years ago, the only large herbivores in many ecosystems were long-necked dinosaurs called sauropodomorphs. These reptiles were the forerunners of the gargantuan sauropods, the group that included Brachiosaurus and Brontosaurus.

A well-populated breeding ground in southern Patagonia hints at one reason early sauropodomorphs were so successful: They knew how to stick together. When scientists analyzed the eggs and skeletal remains of juveniles and adults of a species known as Mussaurus patagonicus, they found that the fossils were segregated by age, suggesting that the dinosaurs raised their young as a community. 

The 193-million-year-old site represents the earliest evidence of herd-living in dinosaurs, the team reported on October 21 in Scientific Reports.

“People have known for a long time that the more advanced dinosaurs, the ones that lived in the late Jurassic and Cretaceous, especially the large sauropods…moved and lived in herds,” says Jahandar Ramezani, a geochronologist at MIT and coauthor of the findings. “But the question has always been, when did this behavior start?”

The species that he and his colleagues investigated was originally discovered in Argentina’s Laguna Colorada Formation in the 1970’s. In recent years, the team has excavated dozens more Mussaurus specimens of all ages from the site. The youngsters appear to have walked on four legs before becoming bipedal as they matured. The largest adult specimen would have reached an estimated 1504.8 kilograms (about 1.7 tons) in size.

In total, the researchers examined more than 100 eggs and 80 Mussaurus skeletons from an area of about 1 square kilometer (about 0.39 square miles). The team used x-ray imaging to peer inside the eggs and confirm the embryos’ identities. To determine the juvenile dinosaurs’ ages, the researchers counted the annual growth rings visible in fine slices of leg bone under the microscope.

The fossils were found close together, in three levels within an area of reddish-brown siltstone that appears to have been a shared breeding ground, Ramezani says. He and his colleagues observed that many of the fossils were grouped by age, including several nests with clusters of eight to 30 eggs, a collection of 11 juveniles that were the same size and appeared to have died and been buried together, and adults alone or in pairs.

[Related: This Australian behemoth is officially the largest dinosaur on the continent]

“This age segregation is basically key; it tells us that this is not something like a simple family structure, being parents and juveniles together,” Ramezani says. “These are colonies of a lot of dinosaurs that are basically taking care of the young [and] the eggs together.”

The sediments found amongst the fossils indicate that the site was located near a short-lived lake, he says. The researchers speculate that the dinosaurs might have died after a long drought, then been rapidly buried in windblown dust.

Mixed in with this dust there was also some volcanic ash, which contains minute zircon crystals. These crystals have high levels of uranium that over time decays into lead. By analyzing the amounts of both elements in the crystals, Ramezani and his team were able to calculate the age of the sediments the dinosaurs were buried in. They found that the site was 193 million years old, pushing back the earliest recorded herding behavior in dinosaurs by at least 40 million years. 

However, it’s likely that dinosaurs began gathering in herds to forage and care for young together even before Mussaurus appeared on the scene. This strategy may have enabled sauropodomorphs and possibly other early dinosaurs to thrive and eventually dominate ancient ecosystems, Ramezani says. 

In fact, paleontologists have reported nesting colonies of other early sauropodomorphs from China and South Africa that appear to have lived around the same time. 

“They have some ideas based on the rocks what the approximate ages would be, but they don’t have the exact ages,” Ramezani says. “We definitely need more information, better [estimates of] ages, to be able to put these pieces of the puzzle together and complete the picture of this social behavior.” 

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Nearly 100 million years ago in present-day Myanmar, a tiny crab got lodged in tree resin and was likely entombed while still alive. While unfortunate for the crab, this situation has given scientists a rare glimpse of a time when the ancestors of today’s crustaceans were first leaving the ocean.

The specimen not only represents a new species, but it’s also the oldest crab to be found preserved in amber, the researchers reported on October 20 in Science Advances. The crab’s gills indicate that it was aquatic or amphibious, and that ancient crabs ventured onto land and freshwater environments earlier than the sparse fossil record has previously shown. 

“This is the first crab of the dinosaur era trapped in amber,” says Javier Luque, a paleobiologist at Harvard University and coauthor of the findings. “And because it’s trapped in such an exquisite way, it is the most complete crab ever discovered, to the level of not missing a single hair.”

Crabs have existed for over 200 million years, he says. However it was during the Cretaceous Period, which ran from 145 million to 66 million years ago, that the crustaceans really hit their stride. During the so-called Cretaceous Crab Revolution, the group diversified, traveled around the world, and began to play a major role in the ecosystems they settled in. 

Today’s crabs are a diverse bunch, ranging in size from less than an inch to 12 feet across. Some dwell in the ocean, while others live in brackish or freshwater and even on land.

Early representatives of the group departed the sea to conquer these terrestrial and aquatic habitats on multiple separate occasions. Based on the genetics of living species, scientists estimate that nonmarine crabs split off from their relatives around 130 million years ago. However, there are few fossils to document this transition; the oldest-known claws and upper shells, or carapaces, of freshwater and terrestrial crabs are roughly 75 million to 50 million years old.

The unlucky crab that Luque and his team describe in the new paper was among a batch of amber pieces initially collected by miners and later acquired from a mineral store in China by the Longyin Amber Museum in Yunnan Province in 2015. The researchers examined the fossil under the microscope and used a technique called micro-CT scanning to create three-dimensional digital reconstructions of the crab’s body. 

[Related: What would a dinosaur taste like?]

They saw that the exceptionally preserved fossil included delicate features such as antennae, large compound eyes, mouthparts covered in fine hairs, and at least six pairs of gills. “Those soft tissues are really hard to preserve,” Luque says. “They’re among the first to decompose and degrade.”

The lifelike position and complete nature of the fossil hint that the crab was alive and struggled to escape when it became engulfed in resin, he adds. The specimen was smaller than most other living or extinct crab species, with a carapace measuring 2 millimeters (0.08 inches) wide and a leg span of 5 millimeters (0.20 inches). It’s unclear whether this crab, which the researchers named Cretapsara athanata, was partially grown or simply a very petite adult. 

The earliest crabs were very different from those alive today, and their appearance was “mostly something in between lobstery-looking and crabby-looking,” Luque says. C. athanata, however, has several features in common with present-day crabs, including the shape of its carapace and long legs. “For a second I couldn’t believe my eyes,” Luque says. “It looks so modern in many ways.” 

The fossil suggests that this familiar crab body plan was already present in the mid-Cretaceous, when many of the ancestors of modern crabs emerged, he says.

Luque and his team also noticed that C. athanata lacked the spongy lung-like tissue that is found in land crabs. They speculate that the ancient crab lived in brackish or freshwater settings near the coast, or perhaps moved between land and water. It may have lived in shallow pools of water on the forest floor or even in the moist hollows of trees. 

It’s possible that C. athanata had a lifecycle resembling that of the land-dwelling Christmas Island red crab, which travels to the coast to release their larvae into the ocean. A few weeks later, the young crabs return to the shore en masse and eventually migrate inland. 

It’s difficult to determine C. athanata’s lifestyle from a single specimen trapped in amber. Still, as the oldest nonmarine crab yet to be discovered, C. athanata fills in a gap in our understanding of how crabs began moving into terrestrial and freshwater environments, Luque says. This challenging shift has only been undertaken a few times across the animal kingdom.

“It is incredible that crabs alone have done it 12 times in the last 100 million years,” Luque says. “Evolution did something well with these crabs that’s allowed them to go to places that none other of their relatives have before.”

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When it comes to snakes, the modern world offers an embarrassment of riches. There are almost 4,000 different snake species alive today, placing the group not far behind mammals in terms of diversity. The snakes are also varied in the types of food they prefer to consume: Some feast only on earthworms, while others can swallow an entire deer. 

“T​​hey just have an astounding variety of diets,” says Michael Grundler, a postdoctoral researcher in ecology and evolutionary biology at the University of California, Los Angeles. He and his colleague Daniel Rabosky, of the University of Michigan, wanted to know how this group became so diverse and successful. 

When they analyzed both the diets and the evolutionary relationships amongst hundreds of present-day snakes, the pair found that the mass extinction that finished off the dinosaurs was a game-changer for the limbless reptiles. Early snakes slithered into newly vacant ecological niches and rapidly evolved the ability to go after a wide array of prey, the scientists reported on October 14 in the journal PLOS Biology.

Little is known about the earliest chapters of snake evolution because the animals are rarely preserved as fossils, Grundler says. So he and Rabosky used information from living species to probe their history. They gathered more than 34,000 reports of the diets of 882 species based on observations of wild snakes and dissected museum specimens. The researchers also drew upon family trees determined from the genetics of modern snakes.

“With those two pieces of information we can make inferences about what extinct species might have looked like long ago,” Grundler says. The team used mathematical models to reconstruct how quickly these ancestral snakes might have changed through time as their diets shifted.

The earliest snakes were probably insect-eaters. However, by the time the dinosaur-killing asteroid arrived 66 million years ago, they’d branched out a bit to dine on vertebrate prey.

“Shortly after that event we find a signal of a big explosion in dietary diversity,” Grundler says. “The survivors of that event went on to evolve this huge range of eating styles that we see today.”

After this burst of activity, many groups also changed their diets very quickly when they journeyed to new locations. One particularly striking example is the dipsadine snakes, a subfamily with more than 700 species that include hognose snakes and false coral snakes. After arriving in South America, “They just exploded in their dietary diversity in a relatively short period of time,” Grundler says. “They evolved to specialize on earthworms, fishes, frogs, slugs, eels—even other snakes.”

[Related: These snakes wiggle up smooth poles by turning their bodies into ‘lassoes’]

On the other hand, some groups of snakes evolved far more slowly. Blind snakes, which feed mainly on colonial insects like ants and termites, appear to have had similar diets for tens of millions of years, Grundler says. 

The findings highlight how opportunities such as the disappearance of hungry competitors (and the rise of rodents and other delicacies) and moving into new habitats “shape evolutionary fortunes,” he adds.

For snakes, this led to a spectacular collection of adaptations for dining on mammals, birds, fish, amphibians, other reptiles, and a host of invertebrates. The emergence of venom allowed vipers and other ambitious snakes to bring down prey that might otherwise be too dangerous for them to subdue. 

There were also more unusual developments; members of the Pareinae subfamily in southeast Asia that dine exclusively on snails have more teeth on one side of their jaw than the other. This makes it easier for the snakes to “get in and rake the body of the snail” to extract the hapless animal from its asymmetrical shell, Grundler says.

At the same time, he and Rabosky observed, even snakes that are apparently specialized for one kind of prey have been known to gobble up other animals that come their way. This capacity for adventurous eating may have helped early snakes innovate and thrive throughout their history. 

While the new analysis covers all the major snake families, Grundler says, it only includes around a quarter of known species. “There’s thousands of species of snakes for which we know very little,” he says. “We still have a long way to go.” 

The next step will be to gather more information about these mysterious snakes and search for more information from the remains of their extinct relatives.

“This [work] all relies on living species,” Grundler says. “If we’re able to get better observations of diets of fossil snakes and include those in our analysis, that would be really important to do.”

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Several hundred million years ago, during the time when Earth had a single supercontinent called Pangaea, ancient plants endured a punishing ice age.

A new analysis based on fossilized plants and climate models indicates that these frigid conditions would have limited tree cover across Pangaea. This in turn would have had profound implications for the climate and the course of plant evolution, as reported on October 11 in the journal Proceedings of the National Academy of Sciences. Understanding how vegetation fared in this harsh landscape can also help us prepare for the future, says William J. Matthaeus, a biologist at Baylor University and coauthor of the study.

“There is a wealth of information about extinct plants that we can leverage to make quantitative inferences about the way that the Earth was throughout natural history,” he says. “And if we have any hope of understanding the way our climate is going to change in the future we really need to do that.”

During an ice age, glaciers advance and retreat over a series of glacial and relatively warmer interglacial periods. We’re technically in the midst of an ice age now, living through an interglacial that started about 11,000 years ago. The previous one, known as the late Paleozoic ice age, spanned roughly 340 to 285 million years ago. It was marked by periods when glacial ice covered much of the land and oceans receded, as well as dramatic swings in atmospheric carbon dioxide and oxygen levels. 

The plant community during this ice age looked very different from that of today, Matthaeus says. One group known as lycopsids, which today include tiny wetland plants such as clubmosses, often grew to tens of meters tall. Others such as pteridosperms, which were notable for their fern-like fronds, have no living relatives. There were also ancestors or early relatives of more familiar trees such as conifers. 

These plants would have influenced the surrounding climate in a number of ways, Matthaeus explains. Plants—and trees in particular—produce oxygen and lock up vast amounts of carbon. Their root systems break up rocks, which then dissolve more quickly and alter the chemical composition of freshwater runoff and the ocean surface, changing the amount of carbon the ocean can store. Plants also pull in, store, and release water back into the atmosphere. “They sort of buffer the water cycle,” Matthaeus says. “The amount of [rainwater] that goes directly back into the atmosphere in place, versus becoming runoff or groundwater, is strongly influenced by plants.”

[Related: Dire wolves are actually ice age mega-foxes]

He and his colleagues wanted to know how widespread forests might have been during the late Paleozoic ice age. They first used fossil measurements to determine several characteristics relating to how the ancient plants used water and carbon. One feature they looked at was the stomata, tiny openings in plant leaves that control how much carbon dioxide, water vapor, and oxygen enter and exit.  

“This is a pretty important structure in terms of the way that plants function, because they don’t want to lose any more water than they have to, but they want to get all the carbon dioxide that they can,” Matthaeus says. Information like this helped the researchers understand how the plants functioned, and in turn how that might influence forest cover.

The researchers also used computer models to simulate climate conditions the plants faced during glacial and interglacial cycles. Based on the environmental and anatomical constraints they identified, the team found that plants probably could have grown in many places across Pangaea. These estimates largely agree with locations where fossilized plants have been found, Matthaeus says. 

However, these reconstructions didn’t account for the immense stress that freezing temperatures can put on plants; some species perish after less than a day of exposure. The researchers estimated that dangerously chilly conditions would have reached plants even in many glacier-free areas.  

“This is an ice age, and so a lot of the Earth’s surface was very cold at different times of the year in both the glacial and interglacial scenarios,” Matthaeus says. This likely limited forest distributions beyond the other variables they considered such as light levels, average temperature, and water availability, he says. “If we’re right about freezing, then probably forest cover could be really restricted from where people have thought it might have been in the past.”

Cycles of freezing and thawing temperatures, during which plants were killed off and began to regrow, would have had complicated effects on runoff, erosion, and carbon dioxide levels, the researchers concluded. As a next step, Matthaeus and his team will further investigate the role that periodic freezes would have had on paleozoic plants. More research is also needed on the poorly-understood topography of Pangaea, which is another important variable that would have influenced forest cover and climate during the ice age, he adds.

These freezes might also have helped particularly hardy plants, including the ancestors of the trees that make up today’s taiga and boreal forests, dominate the plant community while many other trees went extinct. “The combination of seasonal drought and freezing really gave plants that could survive those things a huge evolutionary advantage,” Matthaeus says, “and conifers would certainly be a candidate for that.”

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These days, the Jezero crater on Mars is an arid, barren depression. But it was a very different place billions of years ago, images taken by NASA’s Perseverance rover have revealed. 

Scientists examined layers of sediments and rocks lodged in the sides of the crater, and determined that it was once a placid lake and river delta. That ultimately changed when powerful flash floods struck the crater, pummeling it with boulders swept in from the rim or beyond.

The geological history of the Jezero crater could help scientists understand how the Red Planet changed from being wet and possibly habitable into a harsh desert world. It  also provides a compelling target to search for traces of life, says Benjamin Weiss, a planetary scientist at MIT. “Definitely we hit the jackpot here,” says Weiss, whose team reported the findings on October 7 in Science.

The surface of Mars was once dotted with massive crater lakes. The 28-mile Jezero crater held one such lake around 3.7 billion years ago. Scientists have previously detected fan-shaped structures along the edges that resemble deltas on Earth, suggesting that ancient rivers carried water, sand, and mud into the crater. 

“We know that we’re dealing with a lake and river system; these tend to be very habitable on Earth,” says Amy Williams, an astrobiologist at the University of Florida and coauthor of the study. That made the Jezero crater an inviting site for the ​Mars 2020 mission, which deployed the Perseverance rover to explore environments that could have hosted microbial life. 

[Related: After a few hiccups, NASA’s Perseverance begins its main missions on Mars]

On February 18, Perseverance touched down on the floor of the crater, several kilometers from the relatively well-preserved westernmost delta. Over the next three months, the rover stayed put while researchers made sure its instruments and software were working. This gave Perseverance plenty of time to snap pictures of the main fan and an isolated hill the team called Kodiak butte about a half mile south. Leftover “islands” like Kodiak indicate that the delta was much larger in the past, before it was worn down and fragmented by billions of years of erosion, Weiss says.

When he and his team analyzed the images of both sites, they observed sloped layers of sediments.

“These delta deposits tell us that the lake levels within Jezero changed a lot through time, implying that the climate was warm enough (at least in this region) to allow large rivers to flow and fill a lake while forming a delta,” Stefano Nerozzi, a planetary geologist at the University of Arizona who was not involved in the research, told Popular Science in an email. 

When a river flows into a lake, heavier objects are the first to settle, Williams says. Lighter materials tend to travel farther from the mouth of the river. She and her colleagues were particularly excited by gently dipping beds of fine-grained sediments most visible on Kodiak butte. 

On Earth, such sediments are prime places to look for evidence of past life, says Tanja Bosak, a geobiologist at MIT and another coauthor of the findings. For one thing, they tend to be deposited under gentle conditions. “If there’s any life, nothing grinds it up; if you have boulders bouncing, that will not do good things to your life,” Bosak says. “Another reason is these sediments tend to be chocked full of clay minerals, and clay minerals act like natural sponges for organic matter.” Clays smother this precious cargo and preserve it from sunlight and other hazards for millions of years, she says. 

The team also noticed boulders several feet in diameter sitting atop the older sediment layers of the delta. “These rocks are not the kind of thing that are deposited in a quiescent, low-energy environment like a lake with a lazy river flowing into it,” Weiss says. “To carry such big rocks, you need really intense energetic flows like you’d expect from flooding events.”

[Related: Mars may be too small to have ever been habitable]

Many of the boulders have “nicely rounded” sides, Williams says. “This tells us that they actually have undergone long-distance travel from wherever they came from to be deposited here,” she says. The boulders might be pieces of crater rim that were dislodged and washed into the delta. Alternatively, the boulders might be even older rocks from outside the crater, carried from perhaps as far as 40 miles away, Weiss says.

It’s not clear yet what caused the small-scale flash floods that arrived late in the crater lake’s history. “Maybe we’re capturing the transitioning [of Mars] to the colder and drier conditions of today,” Weiss says. “Right now we don’t know whether this is a sign of the global climate change on Mars or not.”

This question could be answered over the next several years as Perseverance takes a closer look at the rocks and sediments strewn about the delta, and gathers samples that will hopefully be brought to Earth.

The samples could also be researchers’ best chance yet at identifying signs of past life on Mars. “Finding well preserved lower delta deposits means that we have sediments with the highest preservation potential for organic matter, at least by Earth’s standards,” Nerozzi says. “This is definitely the right place to be to look for traces of possible ancient life on Mars.”

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This story originally published on June 27, 2017 and has been updated.

On May 22, 1960, the largest earthquake ever measured struck off the coast of southern Chile. Once the shaking stopped, Denis García, a resident of the nearby port town Corral, noticed something odd. He was searching for his family, not realizing they were safe and on high ground, when he caught sight of Corral Bay. The waters had drawn back, leaving the seafloor bare. García went to investigate. He did not see the 40-foot-high tsunami barreling toward him until it was too late.

Caught in the swirling water, he clung to a piece of debris for hours before meeting another survivor and climbing onto the roof of a house as it floated by, he told interviewers decades later. Meanwhile, the tsunami swept across the Pacific. It’s estimated that the Great Chilean Earthquake and the tsunami that followed claimed more than 5,000 lives.

Around 80 percent of tsunamis begin along the Pacific Ocean’s seismically active “Ring of Fire.” In the United States, Hawaii, Alaska, and the west coast have the highest tsunami risk. But these mega waves can strike in any ocean, and travel across the sea to cause mayhem far from their source about twice per decade.

Denis García was lucky. Most people do not survive being swept into a tsunami. But there are a few ways you can protect yourself from these natural disasters. Your exact strategy will depend on where you are, and will go a lot more smoothly if you have planned in advance.

“It’s easy to say, ‘That’s not going to be my problem ever,’ and it’s also easy to throw up your hands and say, ‘It’s going to be so bad that there’s really nothing I can do,’” says Carrie Garrison-Laney, a tsunami and coastal hazard expert at the Washington Sea Grant office in Seattle. “Yes, it will be bad, but…there are some things you can do to be prepared in the event that it happens.”

Know the tsunami is coming

Most tsunamis are triggered when earthquakes near the seafloor displace a large amount of water. That water gets pushed out as a series of waves that move outwards in all directions. Undersea volcanic eruptions, landslides, and even meteorites can also spark tsunamis.

Out on the sea, these waves can be hundreds of miles long but no taller than a few feet and travel at the speed of a jet plane, up to 500 miles per hour. When the waves approach land, they will slow to about 20 or 30 miles an hour and begin to grow in height.

Most tsunamis are less than 10 feet high when they hit land, but they can reach more than 100 feet high. When a tsunami comes ashore, areas less than 25 feet above sea level and within a mile of the sea will be in the greatest danger. However, tsunamis can surge up to 10 miles inland. “It’s really just kind of relentless, the water just keeps on coming and coming and coming for a long time,” Garrison-Laney says.

The tsunami could resemble a wall of water or, more likely, a rapidly rising flood. “It’s not going to look like big, curling waves like you see at the beach,” Garrison-Laney says. “It’s really a very turbulent flow that is rising and flowing onto land pretty quickly.”

Before this happens, though, there may be a few warning signs.

First you’ll need to survive the earthquake, if there was one. After a strong coastal quake, make sure you get to high ground even if an official tsunami warning has not yet been issued. If a local tsunami has been generated it could be mere minutes away. “You cannot wait for the authorities if it’s a significant earthquake and you live along the coast,” says Denis Chang Seng, technical secretary for UNESCO’s Intergovernmental Coordination Group for the Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, the Mediterranean, and connected seas.

As Denis García discovered in 1960, a tsunami can also cause the ocean to withdraw before it arrives, leaving sand and reefs bare. There may be a roaring noise like a train or jet plane as well. “You have to recognize the warning signs from nature itself,” Chang Seng says.

Meanwhile, tsunami tracking centers such as the Pacific Tsunami Warning Center in Hawaii or the National Tsunami Warning Center in Alaska will put out an alert. So be on the lookout for official warnings, sirens, and directions from your local authorities.

“You don’t want to hesitate if you know a warning’s been issued or you’ve felt the ground shaking,” says Laura Kong, director of the International Tsunami Information Center in Honolulu. “You want to get going.”

Get to high ground before the disaster arrives

If you happen to be on a boat in the open ocean, stay there. Otherwise, your best course of action depends on how much time you have before the tsunami arrives.

Your goal, assuming you’re on land, is to evacuate away from the coast. Try to reach someplace 100 feet above sea level or two miles away from the ocean.

If you’re lucky, the tsunami will have been caused by an earthquake far away and won’t arrive for several hours. Take a disaster kit if you have one on hand, and bring your pets with you. If you aren’t sure where to go, there may be evacuation signs you can follow. But pay attention to any instructions from emergency personnel, since they may recommend a different evacuation route than you were planning to take.

[Related: 300 years of tree rings show just how badly hurricanes have soaked the Carolinas.]

If you aren’t certain how far to evacuate, keep going. “If you’re at 20 feet [above sea level] don’t stop, just keep moving uphill,” says Ian Miller, a coastal hazards specialist at Washington Sea Grant who is based in Port Angeles.

As you head for high ground, stay away from rivers and streams. “A tsunami can move up the river very fast, and many people have been caught by surprise,” Chang Seng says.

And plan to evacuate on foot. “If everyone jumps in their car in the same time it’ll just be traffic and no one will get out,” Garrison-Laney says.

If there has already been an earthquake in the area, watch out for downed power lines. Stay clear of buildings and bridges that could shed heavy debris if there’s an aftershock.

You can also buy survival pods intended to protect you from a tsunami, although they are pricey and have yet to prove their mettle.

Take shelter

You may not have enough time to reach high ground before the tsunami arrives. The Seattle Times once asked cross-country athlete Ben Brownlee to run the evacuation route from Long Beach Elementary in Washington State, a particularly vulnerable peninsula in a region due for a massive earthquake. Brownlee can run a mile in under 6 minutes, and he cleared the hazard zone in 15 minutes. With no injuries or earthquake rubble to struggle through, he might have escaped an oncoming tsunami—but just barely. If you can see the wave, you should assume you’re too close to outrun it. Many folks faced with a tsunami have to make do with whatever shelter they’ve got.

That’s where vertical tsunami shelters will come in handy. Ideally, these structures are sturdy enough to withstand the onslaught of water, tall enough to clear the danger zone, and placed in locations where as many people as possible can reach them. Last year, Ocosta Elementary School in Westport, Washington unveiled the nation’s first tsunami evacuation structure. The school’s gymnasium is engineered to withstand an earthquake and tsunami and shelter more than 1,000 people on its roof.

The city of Long Beach is planning to build a tsunami shelter that will resemble an armored hill. Other cities are designing tsunami sanctuaries as well; Newport, Oregon, is turning a forested hill into a refuge that can accommodate 2,300 people.

If you are fleeing from a tsunami and no such havens are available, try to find a sturdy, reinforced concrete building. Climb as high as possible—at least to the third floor—and head for the roof.

“If there’s a large hotel with several stories, that would probably be your best bet rather than any of the vacation homes,” Garrison-Laney says. “It would need to be a building that had a pretty substantial concrete foundation, and even then there’s no guarantee.” After all, most buildings weren’t constructed to withstand the kinds of forces a tsunami will throw at them.

If there are no buildings, try to scramble up a tree.

Hang on tight when the wave hits

If everything else fails, grab a piece of floating debris. Some people have survived by climbing aboard roofs and using them as makeshift life rafts.

If you are caught up in the wave, you’ll face turbulent water filled with rubble. Survival, at this point, is a matter of luck. “A person will be just swept up in it and carried along as debris; there’s no swimming out of a tsunami,” Garrison-Laney says. “There’s so much debris in the water that you’ll probably get crushed.”

Eventually, the wave will pull back, dragging cars, trees, and buildings with it. But even if you’ve made it this far, you’re not totally safe yet. A tsunami is actually a series of waves, and the first one might not be the largest. The coasts are often inundated with several waves over a period of hours.

“People have perished by assuming that the first wave was the extent of the disaster,” Miller says. “There’s always follow-on waves…in the same way that when you throw a pebble into a rain puddle there’s never just one wave.”

So if you are perched in a sturdy tree or on a building and haven’t received the all clear from emergency personnel, don’t come down right away. “I would probably stay up in the tree for three or four hours,” Garrison-Laney says.

If you have made it to secure terrain, wait for the authorities to tell you it is safe to return to low-lying areas. “The coastline could be devastated with flooding and damaged homes and debris fires,” Chang Seng says.

And the tsunami may have weakened structures that it did not sweep away. Several hours after the 2004 Indian Ocean tsunami, Chang Seng drove over a bridge in his home country, the island nation of Seychelles, which is located off the eastern coast of Africa. “I’d just crossed the bridge in a car, then a couple of seconds after that the same bridge collapsed,” Chang Seng says.

Be ready and know your region’s risk

Tsunamis can hoist boulders and sweep buildings right off their foundations. Unlike the ones you normally sea at the beach, these monster waves span the entire water column from seafloor to surface. “It’s very powerful, there’s a lot of energy because when a tsunami comes it’s not just a surface wave,” Chang Seng says. “It’s the whole ocean that moves and comes and sweeps over the coast.”

And it’s hard to have a wave slam into the coastline without threatening people. Over one third of the world’s population lives within 60 miles of the ocean. In 2010, 39 percent of the population of the United States lived in counties directly on the shoreline, and the coast is only expected to become more crowded.

Tsunamis are uncommon in the Mediterranean. “It’s the busiest area in the world in terms of shipping and tourism, so there’s a big risk [from] tsunamis even if it’s rare,” says Denis Chang Seng of UNESCO’s Tsunami Unit & Ocean Observation Services Section.

[Related: The average hurricane season is officially more intense.]

That’s why you need to be prepared in case one of these rare but devastating waves comes to a beach near you. “You must have a plan for your family if you are living along the coast,” Chang Seng says. If your home or office is near the sea, know the tsunami evacuation zone. Map out and practice an evacuation route, and have a kit ready for emergencies. Know your community’s disaster plans. “Every tsunami-prone area should have a tsunami evacuation map where they’ve worked out where the unsafe zones are,” Kong says.

You may also find yourself in a hazard zone when you are visiting the shore. Tourists are especially likely to be caught off-guard. “If you’re on vacation you don’t necessarily want to worry about something like that,” Miller says. But if you are in tsunami territory, it’s best to make a plan for what you would do if disaster did strike. Miller also advises bringing a flashlight if you’re vacationing on the coast. “Just that one thing may make a big difference if you have to do an evacuation at night,” he says.

When a devastating tsunami strikes, scientists review footage from the event to see what they can learn. These videos leave a sobering impression. “In the course of tens of seconds you go from dry land, everything’s normal, to a foot, two feet, several meters, ten feet of water and everything is floating including cars with people in them,” Kong says. “You hear the crunch of buildings getting broken in half by the water.”

Scientists also prepare for tsunamis by running computer simulations to predict which parts of a coastline are most vulnerable and how much time its inhabitants will have before the first wave hits. They can then come up with a plan for different scenarios and plot out evacuation routes.

One reason that the 2004 Indian Ocean Tsunami, which killed 230,000 people, was so devastating is that people were unaware of the danger. They did not realize a tsunami was rushing towards them because there were no regional warning systems. But the tsunami inspired advances in detection and readiness and today, the nations bordering the Indian Ocean are better prepared.

“Now that we’ve had a couple of those big, devastating tsunamis people have a much better idea of what to do,” Garrison-Laney says. Even so, tsunamis can be unpredictable. Earlier this month, a rare tsunami hit the west coast of Greenland. And Japan, the best-prepared nation in the world when it comes to earthquakes, was still devastated by the 2011 quake and tsunami, which reached up to 133 feet. An estimated 16,000 people died, the majority killed by the waves.

So coastal communities should prepare for the worst-case scenario. This can be tricky in areas that haven’t seen a tsunami in some time, like the Pacific Northwest, which was last ravaged by a tsunami in 1700.

“The main thing we don’t know…is where the next tsunami will happen,” Garrison-Laney says. “It’s really just up to coastal communities to make sure that they’re ready, and hopefully it won’t happen before everyone’s ready.”

The post How to survive a tsunami appeared first on Popular Science.

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