Six hours before I gave birth to my son, our labor and delivery nurse started choking.

The cause, we later discovered, was a jar of peanuts that my unsuspecting husband had cracked open for a snack. Our fast-acting (and highly allergic) nurse rushed out of the room and made it to her EpiPen in time. She was OK, to our immense relief, and we managed to not endanger anyone else’s life that night.

But, the scary incident made me want to keep my baby away from peanuts forever.

Don’t do that.

Instead, parents should feed (most) babies peanut-containing foods early and often, new guidelines from the National Institute of Allergy and Infectious Diseases recommend.

“We’re saying that if you introduce peanuts early, you’re going to have a very good chance of preventing peanut allergy,” says Alkis Togias, an allergist at NIAID in Bethesda, Md.

The guidelines, published January 5 in the Journal of Allergy and Clinical Immunology and five other journals, include pages of detailed advice and group kids by different risk factors.

All in all, it’s a lot to process. But in the history of official advice on how to feed your kids, peanuts have always been confusing. Two weeks ago, parents Googling “peanut allergies” might have found guidelines from 2010, which basically said there’s no good reason to avoid peanuts in the first year of life. Or a 2008 report from the American Academy of Pediatrics, which didn’t give a strong statement either way. Or the AAP’s 2000 recommendations, which had some kids avoiding peanuts until age 3.
Last week’s headlines hit upon the apparent contradictions, but the science has actually been steadily marching in one direction — towards peanuts — for years, Togias says.

In 2008, researchers noticed that Jewish kids from the United Kingdom were much more likely to have peanut allergies than Jewish kids from Israel. The reason seemed to be diet-based. Israeli babies usually begin eating peanut-containing foods around 7 months of age. U.K. babies typically wait until after their first birthday.

The results bucked conventional wisdom to delay feeding kids peanuts, and inspired a 2015 trial known as LEAP, for Learning Early about Peanut Allergy. In the trial, 640 babies between 4 and 11 months old with severe eczema and/or egg allergy were divvied up into two groups. One group ate peanut-containing foods. The other avoided them.

It was the first randomized, controlled trial to address the should-I-feed-my-baby-peanuts question. What researchers saw was remarkable: In peanut-fed kids, the incidence of peanut allergy dropped by roughly 70 to 80 percent.

“The results were so impressive that we felt it would be unethical to not come out with these guidelines,” Togias says.

The new guidelines offer different advice depending on certain conditions. For babies without eczema or egg allergies, the guidelines suggest that parents introduce peanut-containing foods around the same time as other solid foods. “There’s really no restriction,” Togias says.
The advice gets tricky for kids with eczema, a skin rash that’s been linked to allergies.

Parents of babies with mild to moderate eczema can stick to the above plan, but peanut-containing foods should be introduced after other solid foods, around 6 months of age. (The allergists I talked to stress that babies should never eat whole peanuts, or even globs of peanut butter — both are major choking hazards.)

Babies with severe eczema and/or an egg allergy should be tested to rule out peanut allergy. If the test is negative, peanut-containing foods get a tentative green light. A doctor can help parents decide if the baby should be fed in the office, or at home with some instructions.

Repeat peanut-feedings is key, says pediatric allergist J. Andrew Bird of UT Southwestern and Children’s Health in Dallas. “Once peanuts are in the diet, they need to stay in the diet,” he says.

It’s unlikely that the United States will see the same drop in peanut allergy reported in the LEAP trial. But even a 50 percent reduction would be huge, Togias says. By his back-of-the-envelope calculation, the U.S. sees roughly 80,000 new cases of peanut allergy every year. “If we cut that in half, we’re saving 40,000 kids right away,” he says.

Still, allergist Katie Allen says the guidelines’ nuanced instructions risk complicating the message that peanuts are OK.

“There’s a lot of merit to these guidelines, but I’m a little worried that the general population will read this and say ‘I’m scared my child has a peanut allergy so I’m going to get him tested,’” says Allen, of Murdoch Childrens Research Institute in Victoria, Australia.

The skin prick test used for screening is not that reliable, she says. And a false-positive result could turn people away from peanuts unnecessarily.

Australia’s guidelines are more straightforward, Allen points out. They recommend that all infants be fed allergenic foods, including peanut butter, within the first year of life (around 6 months, but not before 4 months).

For me, that’s an easier message to digest. Already, Bird has picked up on confusion about the U.S. guidelines. “I saw a mom who said, ‘OK, now this is telling me that my peanut-allergic kid should be eating peanuts every day?’”

That answer to that is a big “no.” These guidelines aim to prevent peanut allergies, not treat them, Bird says.

If the core advice does get out there — to pediatricians, and allergists and parents — it may well keep (at least some) kids from having to grab an EpiPen after getting a whiff of peanut. And that’s something any parent could get behind.

For dinosaurs, the end of the world began in fire.

The space rock that stamped a Vermont-sized crater into the Earth 66 million years ago packed a powerful punch. Any animal living within about a thousand miles of the impact zone was probably vaporized, says paleontologist Stephen Brusatte of the University of Edinburgh in Scotland.

“Everything would have been toast.”

But outside of the impact zone, amid the smoking ruins of the battered planet, some survivors emerged.
Life there was no picnic. Wave after wave of life-threatening disasters pummeled the animals that remained, says paleontologist Nicholas Longrich of the University of Bath in England. Earthquakes. Wildfires. Volcanoes. Acid rain. Dust and gunk in the air, blotting out the sun. “It’s this series of biblical plagues,” Longrich says.

With little light, much plant life perished, and entire food webs collapsed. Life would have been like an ancient Hunger Games, with all living creatures as contestants. The odds were not in their favor. From sea to land to lake to sky, animals suffered incredible losses.

“You’re basically losing all the big herbivores, all the big carnivores, apex predators in the oceans, entire guilds — wiped out overnight,” Longrich says. On land, he adds, anything bigger than a beaver went extinct. Just a few places in North America offer a fossil record of the early years after the extinction, he says, but “there’s no evidence for anything over 10 kilos surviving.”

Tyrannosaurus rex, Triceratops, Ankylosaurus and all other nonavian dinosaurs gone.

A lucky few animals managed to cope with the dramatic changes reshaping their environment, Brusatte says. But why exactly some animal groups survived and others bit the dust is still one of paleontology’s biggest mysteries.
New fossil research is now helping scientists peer back through time, offering glimmers of what might have been: How some animals made it through one of the worst extinction events the planet has ever seen — and how mammals, in particular, came to dominate.

Sussing out animals’ survival strategies could offer hints about how animals today might handle a changing climate, Brusatte says. It might even expose the evolutionary drivers that shaped modern life. After the extinction, evolution went wild, he says. The survivors “had a new world to play in — a new world to conquer.”

Cretaceous catastrophe
Near the very end of the Late Cretaceous Epoch, right before the world blew up, one of the largest mammals in North America may have been noshing on bones.

Didelphodon vorax, a honey badger–looking creature with oddly bulbous teeth, was petite by today’s standards — weighing just about five kilograms. But it was no lightweight. “Pound for pound, it had the greatest bite force of any mammal we’ve ever measured,” says paleontologist Gregory Wilson of the University of Washington in Seattle.
Wilson and colleagues estimated Didelphodon’s bite force from the shape of its fossilized skull. The mammal could snap its jaws together with about 50 pounds of force — enough to crush bones and crack shells, the team reported December 8 in Nature Communications.

This fearsome skill wasn’t enough to save it: After the asteroid hit and global disasters descended, Didelphodon went extinct — just like duck-billed dinosaurs and Pteranodon.

The colossal wipeout of Didelphodon and so many others is plain to see in the fossil record. In Montana’s badlands, where Wilson and colleagues hunt for ancient teeth and bones, tributaries of the Missouri River carve steep bluffs into the earth, exposing slabs of sandstone and siltstone rock. Montana is part of the Western Interior, an ancient seaway that once cut a wide aisle through North America from the Gulf of Mexico to the Arctic.

Much of what scientists know about the dino-killing event, called the Cretaceous–Paleogene, or K–Pg, extinction, traces back to this sweeping tract of land. The area has rocks with fossils from before and after the extinction event. “We haven’t found many places in the world like it,” Wilson says. Spain, France and Romania hold a few dinosaur and mammalian fossils from this time period (and a handful of underexplored spots in India and South America may offer more). But so far, the Western Interior is home to the best land-based record scientists have.

In Montana, the rocks capture a snapshot of time from about 2 million years before the extinction to roughly 1.5 million years after. A thin layer of reddish-brown clay marks the before and after of the asteroid’s impact. “It’s a line in the sand, almost literally,” Brusatte says. Within the clay, here and elsewhere in the world, scientists find elevated levels of iridium, a silvery-white metal carried to Earth via asteroid. Though not visible by eye (scientists need chemical tests to spot it), the metallic dust marks a memory of the impact known as Chicxulub.

All around the globe, Brusatte says, scientists see “a knife-edge separation in the rock” before and after Chicxulub hit. “For over 150 million years you have tons and tons of dinosaur bones, and then literally — Bam! There’s nothing.”

Dinosaurs were among the animal groups hit hardest by the extinction. Others suffered fewer casualties. In what is now northeastern Montana, about half of fish species survived, Wilson reported at an Origins Project workshop at Arizona State University in 2015. Turtles and salamanders seemed to fare the best, losing only roughly a quarter of their species, Wilson and colleagues reported in a series of studies in 2014.

“Most people think that mammals did awesome,” Wilson says. But at least 75 percent of mammals were snuffed out, according to his analysis, which compared fossils present before and after the extinction. Longrich and colleagues put the number even higher: Of 59 mammalian species living in North America during the Late Cretaceous Epoch, about 93 percent died out after the asteroid hit. Those calculations appeared in the Journal of Evolutionary Biology in August 2016.

Still, some species found a way to endure.

Survival strategies
A small body. An aquatic lifestyle. Night vision. An unfussy palate. Any one of these features could have helped survivors withstand the relentless undoing of their ecosystems.

It makes sense. Small animals would have required less food than large ones and may have had an easier time finding shelter. Animals that lived in water could have been buffered from dramatic temperature swings.

Nocturnal animals would have been able to hunt for food when debris-filled skies wrapped the world in gloom. The right diet, in fact, could have been one of the biggest tickets to survival. Among insects, for instance, the difference between survival and demise depended on dietary diversity.

Some insects are adventurous eaters: They feed on lots of different kinds of plants. Other insects are pickier. Leaf miners, for example, typically dine on just one plant species, or a few closely related ones, which made it hard to survive the cataclysm.
These insects burrow through leaves, leaving behind a distinctive trail. Cataloging the trails and other damage patterns on fossil leaves can give researchers a rough idea of the kinds of insects that went extinct — or survived, says Penn State paleontologist Michael Donovan. It’s like a calling card stamped into stone.

Donovan examined 3,646 fossil leaves found in Patagonia, Argentina, from slices of time bracketing the Chicxulub impact. The leaf-mining patterns seen before the impact vanished after the asteroid hit, he and colleagues reported in Nature Ecology & Evolution in 2016.

That suggests a major extinction of leaf-mining insects, a find echoed in previous results from North Dakota. (Though not all perished. Donovan saw new leaf-mining patterns after the extinction.) Other types of leaf damage did persist through the extinction event — damage made by insects that eat many plant species. Unlike leaf miners, these insects took what they could get in the dark days after the impact. “That’s probably a good way to survive,” Donovan says.

This type of strategy may have helped some species adapt to their new habitat, Longrich says, which after the K–Pg extinction “happened to be this post-apocalyptic wasteland world.” It’s like Mad Max of the movies, he says. “A guy who’s super versatile — good at many different things,” Longrich says, “that’s who’s likely to live through an apocalypse.”

Some animals may have already been plugged into the right food chain. When dinosaurs began dying and leaves fell from trees, the bodies and detritus would have littered the ground and washed into rivers and lakes. That would have been a bonanza for the garbage disposal crew. Decaying matter could feed microbes and fish and insects, which could then feed larger animals, like crocodiles and mammals.

Birdlike dinosaurs with beaks could have cracked into another Cretaceous leftover: seeds. The calorie-rich food could have lasted for decades, says paleontologist Derek Larson of the Philip J. Currie Dinosaur Museum in Alberta and the University of Toronto. Other birdlike dinosaurs, with sharp teeth but no beaks, would have had trouble eating seeds. That might explain why they succumbed, while their close relatives — ancestors of modern birds — survived, he and colleagues suggested last year in Current Biology (SN: 5/14/16, p. 11).

Making it as a mammal
Mammals seemed to capitalize on the detritus-based food chain too, Wilson says. He and University of Washington student Stephanie Smith studied fossils found in northeastern Montana from a 1.2-million-year window after the impact. “Fossil mammals are mostly just teeth,” Smith said at the 2016 Society of Vertebrate Paleontology meeting in Salt Lake City. “Luckily, teeth contain a lot of information.”
Smith compared the intricate details of fossil teeth with those from living mammals to learn about the ancient animals’ diets. In Montana, at least, mammals that lived during the first 200,000 years after the extinction event tended to have teeth that were good for crunching insects — “sharp and pointy,” Wilson says. These animals would have had a reliable source of supper. But plant eaters, which have teeth with big basins for grinding and crushing, would have seen their food supplies wither.
For some mammals, a sharp sense of smell could also have offered a competitive edge. Onychodectes tisonensis, a bull dog–sized mammal that lived about 350,000 years after the extinction, had one of the largest olfactory bulbs of any mammal (relative to the cerebrum) — bigger than those found in even expert sniffers like modern dogs and pigs. The smell organs look like two almonds sticking out from the front of the brain, says James Napoli of Brown University in Providence, R.I., who reported the results at the paleontology meeting last year. He and colleagues built a digital model based on a CT scan of an Onychodectes skull unearthed in New Mexico in 1892.

Having big olfactory bulbs means the animal would have been good at nosing out meals, a valuable skill when food is scarce, Napoli says.

Onychodectes belongs to a weird group of mammals called taeniodonts, says study coauthor Thomas Williamson of the New Mexico Museum of Natural History and Science in Albuquerque. “They have bizarre-looking skulls, enlarged forearms, big claws,” he says. The animals may have survived by digging up and eating tough roots and tubers. “We call them the pigs of the Paleocene.”

Paleontologists don’t know for sure if this group of animals lived through the asteroid crash, or if they arose afterward. There’s just one reported taeniodont fossil from the Late Cretaceous — a partial skull from Alberta, Canada.

If taeniodonts did make it through the impact and its aftermath, an aptitude for rooting out hidden food caches would have been useful. If, instead, the animal group emerged later, Onychodectes could have been one of the early examples of mammalian experimentation.

For more than 150 million years, mammals had been “kept under the thumb of the dinosaurs,” Wilson says. After the extinction, with dinosaurs out of the picture, the “Age of Mammals” could begin.

Boomtime for mammals
In the years after the impact, the world was like a school playground that had banished the big kids.

The animals that survived the early hard years gave rise to a slew of new species able to fill the niches left behind by dinosaurs — and all the other creatures that didn’t make it. Before the impact, humans’ ancestors mostly scurried along the ground. But afterward, with fewer predators and competitors, they were free to try out new lifestyles, like living in trees and gliding.

Placental mammals, a group that includes humans, elephants and most mammals living today, experienced a big evolutionary boom, says Thomas Halliday, a paleobiologist at University College London. “Diversification exploded.”

Without dinosaurs breathing down their necks and with fewer competitors, placental mammals had “freedom to evolve in a variety of new directions,” Halliday says. It’s like they were “exploring almost every aspect of the ways of being a mammal.”

When exactly these mammals arose and how much dinosaurs were holding them back remains controversial: Molecular evidence places their origin tens of millions of years before the dinosaurs died. Fossil evidence puts it closer to the K–Pg extinction.
In a series of papers published in 2015 and 2016, Halliday and colleagues analyzed mammalian fossils to sketch out a clearer picture of placental mammals’ history. First, the team built a family tree focused on placental mammals that lived in the Paleocene, the 10-million-year epoch immediately following the extinction. That’s no easy feat, Halliday says, because these animals tend to lack the kind of standout features that would clearly label them as members of one group or another.

So he and colleagues created an exhaustive catalog of 680 body features (such as skull length, tooth number and molar shape) in 177 genera of extinct and living placental mammals and their close relatives. Presumably, animals that shared features were more closely related than those that didn’t. With so many species, the web of potential relationships was astronomical, Halliday says. “There were more possible arrangements … than there are hydrogen atoms in the universe.” The team plugged the data into a computer, which chugged through all the possibilities and came up with the most likely family tree.

Then, the researchers used the tree to calculate rates of evolution. Placental mammals, they found, probably did originate in the Late Cretaceous, but they evolved three times faster after the extinction event than in the 80 million years before it. “We’re talking about new anatomical innovations,” Halliday says: molars good for grinding leaves, limbs adapted for climbing or swimming.

One of these early innovators was Periptychus carinidens, a muscular animal that walked like a bear and had five toes with “weird little hooves,” says University of Edinburgh paleontologist Sarah Shelley. “It’s not like anything alive today.”

Shelley, Williamson and Brusatte described Periptychus fossils found in New Mexico’s San Juan Basin at the 2016 paleontology meeting. “They have really strange cheek teeth,” Williamson says. The teeth are enlarged and conical with big ridges that run from the base to the tip. He thinks Periptychus used its weird chompers to eat hard objects — seeds, perhaps, or unripe fruit.
Periptychus was among the first plant-eating placental mammals to emerge after the extinction — and for a few million years it flourished. Fossils of the animal have been found from West Texas to eastern Montana, Williamson says. “It must have been a highly successful mammal.” But Periptychus couldn’t cope with changes that came later — it died out about 60 million years ago. The animals “were early experiments,” he says, “but they were ultimately dead ends.”

That’s how it goes with evolution, Halliday says. After the dinosaurs died and mammals tested out different modes of life, some found success and others fizzled. “The most successful strategies are honed and the less successful ones are pared away,” he says.

What’s left is what we have today: more than 5,400 different mammal species spread across the world. But descending from an evolutionary winner doesn’t guarantee a safe future. As species carve out an ever more ideal niche, they become more and more vulnerable to extinction, Halliday says. Animals built for a narrow mode of living tend to have a hard time handling disruptions to their environment. And as the climate changes, some species have already begun to suffer. “In the metaphorical sense, we are in the middle of the asteroid strike right now,” he says.

Already, a changing climate has erased pockets of plants and animals across the globe, John Wiens of the University of Arizona in Tucson reported in December 2016 in PLOS Biology. Further warming in coming decades could ramp up extinctions, he warns.

That’s why studying life and death 66 million years ago is still relevant today, Brusatte says. “It’s not just storytelling about the ancient past,” he says. “It can help us understand our modern world,” and maybe even influence conservation strategies to mitigate some of the changes that are happening now.

Fancy flight tricks are a breeze for a new flying robot. Call it an acrobat.

Bat Bot, a lightweight flier with thin silicone wings stretched over a carbon fiber skeleton, can cruise, dive and bank turn just like its namesake, researchers report February 1 in Science Robotics.

Such a maneuverable machine could one day soar up the towering structures of a construction site, flying in and out of steel beams to help keep track of a building’s progress, study coauthor Seth Hutchinson, a roboticist at the University of Illinois at Urbana-Champaign, said in a news briefing January 31.
Other aerial robots, like some drones, aren’t so agile, relying on four whirling rotor blades to lift off the ground, Hutchinson said. These bots also have trouble flying in the wind, because they can exert force in only one direction, he said. Bat Bot’s flexible wings could make it a more versatile flier.

“Bat flight is the holy grail of aerial robotics,” said study coauthor Soon-Jo Chung, a Caltech aerospace engineer. Bats have more than 40 joints in their wings, which give the animals exquisite control over their flight maneuvers. Chung and colleagues re-created nine of the key joints, so their robot could flap its wings in sync, fold each wing independently and move each of its hind legs up and down. At 93 grams, with a wingspan of 47 centimeters, Bat Bot is roughly the size of an Egyptian fruit bat, Chung said.

An onboard computer and sensors let Bat Bot adjust its movements in midair. But the bot still needs a net to land: A crash could bust its electronics. Sticking the landing is the next step, the researchers said. They want Bat Bot to be able to perch — both right-side up and upside down.

Discoveries in a richly appointed 2,600-year-old burial chamber point to surprisingly close ties between Central Europe’s earliest cities and Mediterranean societies. Dated to 583 B.C., this grave also helps pin down when people inhabited what may have been the first city north of the Alps.

An array of fine jewelry, luxury goods and even a rare piece of horse armor found in the grave indicates that “there were craftsmen working in the early Celtic centers north of the Alps who learned their crafts south of the Alps,” says archaeologist Dirk Krausse of the Archaeological State Office of Baden-Württemberg, Germany.
Previous research has established that speakers of Celtic languages inhabited parts of Europe as early as 3,300 years ago. Celtic iron makers appeared in Central Europe by around 2,700 years ago — marking the beginning of that region’s Iron Age — and founded what’s now called the Hallstatt culture.

The grave and a smaller adjoining burial lie in a German cemetery situated across the Danube River from an early Iron Age hill fort called the Heuneburg. Along with yielding insights into long-distance trade and the timing of Europe’s first Iron Age cities, these graves provide the earliest evidence of Hallstatt people elaborately interring women and even children, Krausse and colleagues report in the February Antiquity.

“The main burial represents one of the oldest examples of an exceptionally rich female grave and serves as further testimony of the important social role of certain women in Hallstatt communities,” says archaeologist Manuel Fernández-Götz of the University of Edinburgh, who did not participate in the new study.
While surveying earthen mounds covering graves at the German site in 2005, Krausse’s team noticed a gold-plated bronze brooch fragment lying on the ground. An excavation revealed that the brooch came from the grave of a 2- to 4-year-old child whose skeleton was surrounded by gold and gold-plated jewelry.
It turned out that the child’s grave was an addition to a larger burial chamber. Because farming activity threatened the site, cranes were used in 2010 to hoist out the chamber and surrounding soil in a block weighing 80 metric tons. Researchers excavated the tomb at Krausse’s facility.

Planks of oak and silver fir formed the chamber. Comparisons of growth rings in the planks with previously dated tree rings in the region indicate that the tomb was built in 583 B.C. Previous excavations over the past decade had suggested that the Heuneburg and several other early Iron Age settlements in Germany and France were the first cities north of the Alps, but the grave provides the most precise date yet. Prior to this find, settlements dating to between 2,200 and 2,000 years ago have traditionally been considered the first Central European cities.

Inside the chamber, the team discovered a 30- to 40-year-old woman’s headless skeleton. Her lower jaw and skull were found at two other spots in the grave. Objects placed on and around the skeleton included gold, bronze, amber and jet jewelry and brooches. Decorative styles of some items showed Mediterranean influences. Researchers also found two pairs of boar tusks mounted on large pendants. Each pair of tusks curves around two bronze strips and bronze bells hanging from a smaller pendant.

Another woman’s skeleton and pieces of bronze jewelry rested in a corner of the chamber. It’s unclear whether both bodies were buried at the same time.

A decorated bronze sheet found near the second skeleton’s feet was a piece of armor, called a chamfron, that covered a horse’s forehead, the researchers say. Traces of plant netting and fur preserved on the inside surface of the sheet come from padding, they suspect. CT scans revealed remains of an iron horse bit at one end of the sheet, where it fit in the mouth.

This is the first chamfron found at a Hallstatt site. It resembles horse armor from around the same time found in several Mediterranean cultures, Krausse says.

“The tide is finally shifting” toward accepting links between early European Iron Age cities and societies south of the Alps, says anthropologist Bettina Arnold of the University of Wisconsin–Milwaukee. She suspects that, as at some other Iron Age graves, the elite woman’s burial chamber was looted or material was removed for ritual reasons shortly after interment. Such burials typically included a wagon and metal vessels, but these are missing in the woman’s spacious grave. “This grave is a puzzle, and Hallstatt culture is still enigmatic,” Arnold says.

High-energy ion collisions have produced the swirliest fluid ever discovered, in a state of matter that mimics the early universe.

To create the überwhirly liquid, scientists slammed gold ions together at velocities approaching the speed of light at Brookhaven National Laboratory in Upton, N.Y. Such collisions, performed in Brookhaven’s Relativistic Heavy Ion Collider, cook up an ultrahot fluid, re-creating the state of the universe millionths of a second after the Big Bang, before protons and neutrons had formed. In this fluid, known as a quark-gluon plasma, the constituents of protons and neutrons — quarks and gluons — intermingle freely (SN: 12/10/16, p. 9).

Scientists already knew that this fluid is the hottest ever produced in a laboratory, and that it has almost no viscosity. Now, physicists can add one more unusual property to the list. The quark-gluon plasma created in such collisions has an average vorticity — or swirliness — of about 9 billion trillion radians per second, researchers from the STAR Collaboration report online January 23 at arXiv.org. That’s vastly more than other known fluids. Even the core of a supercell tornado has a vorticity of only 0.1 radians per second.

To measure vorticity, the scientists studied a quantum mechanical property called spin from particles produced in the collision known as lambda baryons. The spin, an intrinsic type of angular momentum, tends to align with the vorticity of the fluid, providing a window into the plasma’s gyrations.

African penguins have used biological cues in the ocean for centuries to find their favorite fish. Now these cues are trapping juvenile penguins in areas with hardly any food, scientists report February 9 in Current Biology.

It’s the first known ocean “ecological trap,” which occurs when a once-reliable environmental cue instead, often because of human interference, prompts an animal to do something harmful.

When juvenile Spheniscus demersus penguins off the Western Cape of South Africa leave the nest for their maiden voyage at sea, they head for prime penguin hunting grounds. But the fish are no longer there, says Richard Sherley, a marine ecologist with the University of Exeter Environment and Sustainability Institute. Increased ocean temperatures, changes in salinity and overfishing have driven the fish eastward.
Penguins are doing what they’ve evolved to do, following signs in the water to historically prosperous habitats. “But humans have broken the system,” Sherley says, and there’s no longer enough fish to support the seabirds.

Sherley estimates that only about 20 percent of these African penguins survive their first year, partly because they can fall into this ecological trap.
Ecological traps have been documented on land for decades. There has been a lot of speculation about traps in the ocean, but this study is the best evidence so far, says Rob Hale, an ecologist with the University of Melbourne.
“Hopefully the study will generate more interest in examining ecological traps in the ocean so we can better understand when and why traps arise, how they are likely to affect animals, and how we can go about managing their effects,” Hale says.

This trap may have occurred because of how penguins find their food. Researchers think penguins can sense a stress chemical that phytoplankton release when being eaten. Penguins eat sardines, which eat phytoplankton. Usually the chemical, dimethyl sulfide, signals to penguins where the fish are feasting on phytoplankton. But phytoplankton can release the compound in other situations, like in rough water. The signal is still sent, but there are no fish.

“You have a cue that used to signal high quality in an environment, but that environment has been modified by human action to some extent,” Sherley says. “The animals are tricked or trapped into selecting a lower quality habitat because the cue still exists, even though there’s high quality habitat available.”

Adult penguins have adapted to the trap and shifted their hunting patterns to follow the fish east. Sherley says they’re not sure how adults learned to avoid the problem, but that there must be a way that juveniles who survive to adulthood also adapt.

Researchers also tracked juvenile penguins from the Namibia and Eastern Cape of South Africa breeding regions. The eastern penguins have been unaffected by the trap because the fish have moved closer to them. The Namibia population is being barely sustained by the goby, a junk food fish that appears to be taking over the areas previously inhabited by sardines and anchovies.

The Western Cape penguins have been most affected. The population has declined 80 percent in the last 15 years — from 40,000 breeding pairs to 5,000 or 6,000, Sherley says. He estimates that if juvenile penguins hadn’t been falling victim to this trap, the Western Cape population would be double its current levels.

If the loss of fish off the Western Cape of South Africa can’t be reversed, Sherley speculates the two most likely outcomes are an African penguin extinction or an ecosystem shift. Current penguin conservation efforts protect penguin breeding areas, but the study suggests that the protections may be insufficient because the ecological trap is far from the breeding grounds.

Short bouts of suffocating conditions can desolate swaths of seafloor for decades, new research suggests. That devastation could spread in the future, as rising temperatures and agricultural runoff enlarge oxygen-poor dead zones in the world’s oceans.

Monitoring sections of the Black Sea, researchers discovered that even days-long periods of low oxygen drove out animals and altered microbial communities. Those ecosystem changes slow decomposition that normally recycles plant and animal matter back into the ecosystem after organisms die, resulting in more organic matter accumulating in seafloor sediments, the researchers report February 10 in Science Advances.
Carbon is included among that organic matter. Over a long enough period of time, the increased carbon burial could help offset a small fraction of carbon emitted by human activities such as fossil fuel burning, says study coauthor Antje Boetius, a marine biologist at the Max Planck Institute for Marine Microbiology in Bremen, Germany. That silver lining comes at a cost, though. “It means your ecosystem is fully declining,” she says.

“We need to pay more attention to the bottom of the ocean,” says Lisa Levin, a biological oceanographer at the Scripps Institution of Oceanography in La Jolla, Calif. “There’s a lot happening down there.” The new work shows that scientists need to consider oxygen conditions when tracking how carbon moves around the environment, says Levin, who was not involved in the research.
Some oxygen-poor, or hypoxic, waters form naturally, such as the suffocating conditions caused by a lack of churning in the deep realms of the Black Sea (SN Online: 10/9/15). Other regions lose their oxygen to human activities; fertilizer washing in from farms nourishes algal blooms, for example, and the bacteria that later decompose that algal influx suck up oxygen. Rising sea-surface temperatures could worsen these problems by decreasing the amount of dissolved oxygen that water can hold and making it harder for ocean layers to mix, as warmer waters remain on top (SN: 3/5/16, p. 11).
Scientists have noticed increased carbon burial in hypoxic waters before. The mechanism behind that increase was unclear, though. Boetius and colleagues headed out to the Black Sea, the world’s largest oxygen-poor body of water, and studied sites along a 40-kilometer-long stretch of seafloor. (Military activities in the region following Russia’s annexation of Crimea limited where the researchers could study, Boetius says.) Some sites were always flush with oxygen, some occasionally suffered a few days of low oxygen, and others were permanently oxygen-free.

The ecological difference between the sites was stark. In oxygen-rich waters, animals such as fish and starfish flourished, and little organic matter was deposited on the seafloor. In areas with perpetually or sporadically low oxygen, the researchers reported that oxygen-dependent animals were nowhere to be seen, and organic matter burial rates were 50 percent higher.

Bottom-dwelling animals are particularly important, the researchers observed, helping recycle organic matter by eating larger bits of debris sinking from the surface ocean and by mixing oxygen into sediments during scavenging. What’s more, the researchers found that the microbial community in oxygen-poor waters shifted toward those microbes that don’t depend on oxygen to live. Such microbes further limit decomposition by producing sulfur-bearing compounds that make organic matter harder to break down.

Depending on the size of the area affected, animals could take years or decades to return to previously hypoxic waters, Boetius says. Some of the studied sites experienced low-oxygen conditions for only a few days a year yet remained barren even when oxygen returned. The absence of animals prolongs the effects of hypoxic conditions beyond the times when oxygen is scarce, she says.

BOSTON — For the first time since the Viking missions to Mars in the 1970s, NASA is making the search for evidence of life on another world the primary science goal of a space mission. The target world is Jupiter’s moon Europa, considered possibly habitable because of its subsurface ocean.

The proposed mission, which could be operational in the next two decades, calls for a lander with room for roughly 43 kilograms of science instruments. They include a robotic arm to scoop samples and others to analyze the chemistry of the Jovian moon’s icy surface (SN: 5/17/14, p. 20). “It’s the first time in human history that we have the ability to design instruments to detect life within our own solar system’s backyard in the next 20 years,” astrobiologist and planetary scientist Kevin Hand said February 17 at the annual meeting of the American Association for the Advancement of Science. Hand’s team submitted a 264-page report describing the potential mission to NASA on February 8. The report is now open for review by the scientific community.

A major concern is taking precautions to prevent contamination of Europa by microbes from Earth. “These are important for protecting Europa for Europans,” said Hand, who works out of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. His team proposes baking the spacecraft to kill as many microorganisms clinging to the exterior of the lander as possible.

Decontamination precautions are important not only for protecting the life that’s on the world being explored, notes biologist Norine Noonan of the University of South Florida St. Petersburg. They are also important for the science goals of the potential mission. “You don’t want to send a $2 billion spacecraft somewhere to discover E. coli,” Noonan says.

Chimps with little social status influence their comrades’ behavior to a surprising extent, a new study suggests.

In groups of captive chimps, a method for snagging food from a box spread among many individuals who saw a low-ranking female peer demonstrate the technique, say primatologist Stuart Watson of the University of St. Andrews in Fife, Scotland, and colleagues. But in other groups where an alpha male introduced the same box-opening technique, relatively few chimps copied the behavior, the researchers report online February 7 in the American Journal of Primatology.
“I suspect that even wild chimpanzees are motivated to copy obviously rewarding behaviors of low-ranking individuals, but the limited spread of rewarding behaviors demonstrated by alpha males was quite surprising,” Watson says. Previous research has found that chimps in captivity more often copy rewarding behaviors of dominant versus lower-ranking group mates. The researchers don’t understand why in this case the high-ranking individuals weren’t copied as much.

The spread of new behaviors in groups of monkeys and apes depends on a variety of factors — including an innovator’s social status, age and sex — that can interact in unpredictable ways. “That’s why social learning in groups is so interesting to study,” says Elizabeth Lonsdorf, a primatologist at Franklin & Marshall College in Lancaster, Pa., who did not participate in the research.

In the new investigation, perhaps animals were monitoring potential threats from the alpha males more than their box-opening skills. “Alpha male chimps are large, powerful and prone to temper tantrums, so it makes sense to be vigilant for signs of what they’ll do next,” Watson says.

It’s also possible that lower-ranking chimps are sometimes unwilling to copy rewarding behaviors in the presence of a dominant chimp, suggests Lonsdorf. Researchers have reported this form of social deference in capuchin monkeys and rhesus macaques.

Watson’s team studied 38 chimps housed at a research facility in Texas. A low-ranking female from each of two groups and a dominant male from each of two other groups were trained to open a box and remove a piece of fruit. They then performed this feat in front of their home groups during two 20-minute sessions on consecutive days. Trained chimps moved a sliding door on the box up or down until it locked to reveal one of two chambers containing the food. Following each demonstration, group members had eight hours to manipulate the box however they liked.
Individuals who watched low-ranking chimps open the box, but not those who observed dominant chimps do the same, used the demonstrated technique as their first choice more often than expected by chance.

Some, but not all, chimps could have figured out how to open the box on their own, Watson suspects. Of 15 chimps from nonexperimental groups — each given 20 minutes to manipulate the fruit box — five failed to open it.

Unexpectedly, two low-ranking female chimps from different groups discovered a way to game the experimental box after watching dominant males open it. These animals realized that the contraption held two pieces of fruit, one in an upper chamber exposed by sliding the door down until it locked and another in a lower chamber revealed by sliding the door up to lock. Each chimp managed to slide the door up and down just enough, without locking it, to snatch both snacks.

In one group, the alpha male, who had originally demonstrated the locking technique to his group, started copying the low-ranking female’s superior approach. In the other group, two high-ranking females adopted the innovative box-opening method after seeing it performed by their social inferior.

Watson doesn’t know if low-ranking chimps are particularly apt to devise clever behaviors that others copy. It wouldn’t be surprising, he says, since chimps low on the social totem pole typically get less food than others and need to supplement their diets in creative ways.

In wild chimp communities, it’s unclear why certain novel behaviors catch on, Lonsdorf says. For example, young females move to new groups at sexual maturity, so they may bring useful knowledge from one community to another. In one reported case, chimps apparently learned how to use branches and other probes to collect and eat ants after observing the behavior in a recently arrived young female (SN: 2/9/13, p. 20).

Amid a flurry of cabinet appointments and immigration policies, the Trump administration has announced one thing it will not do: pursue policies that protect transgender children in public schools.

The Feb. 22 announcement rescinds Obama administration guidelines that, among other protections, allow transgender kids to use bathrooms and participate in sports that correspond with their genders, and to be called by their preferred names and pronouns.

In a Feb. 23 news briefing, White House press secretary Sean Spicer said that this is a states’ rights issue. “States should enact laws that reflect the values, principles, and will of the people in their particular state,” he said. “That’s it, plain and simple.”

But this “plain and simple” move could be quite dangerous, even deadly, science suggests. Transgender children, who are born one biological sex but identify as the other, already face enormous challenges as they move through a society that often doesn’t understand or accept them. Consider this: Nearly half (46.5 percent) of young transgender adults have attempted suicide at some point in their lives, a recent survey of over 2,000 people found. Nearly half. For comparison, the attempted suicide rate among the general U.S. population is estimated to be about 4.6 percent.

What’s more, a 2015 study in the Journal of Adolescent Health found that transgender youth are two to three times as likely as their peers to suffer from depression and anxiety disorders, or to attempt suicide or harm themselves. These troublesome stats, based on a sample of 180 transgender children and young adults in Boston ages 12 to 29, applied equally to those who underwent male-to-female transitions and those who underwent female-to-male transitions.

The science is clear: Many transgender kids already have to overcome big challenges. To have the federal government proclaim that it won’t stop states from denying equal protection to transgender children makes a difficult situation even worse.

The American Academy of Pediatrics agrees. On February 23, AAP president Fernando Stein issued a statement condemning the new guidelines. “Policies excluding transgender youth from facilities consistent with their gender identity have detrimental effects on their physical and mental health, safety and well-being,” he wrote. “No child deserves to feel this way, especially within the walls of their own school.”

As that statement points out, policies that run counter to a child’s gender identity can cause harm in several ways. One obvious way comes from the physical effects of not having access to bathrooms. In a study of 93 transgender adults, 68 percent reported having been verbally harassed while trying to use a public bathroom, and 18 percent said they had been turned away from a bathroom. To avoid these confrontations, transgender people often resort to not drinking water or simply holding in their urine, measures that can cause dehydration or urinary tract infections, that same survey found.
Those are the experiences of transgender adults who were aware of the health effects of not using the bathroom. Now think about how a young transgender child in school might navigate that situation. A school bathroom can be a scary place for any first grader, let alone one who risks ridicule or worse for walking into the boys’ or girls’ room.

Beyond the physical harms of not having access to a bathroom, restrictive policies also carry heavy psychological harms. Rules that fail to recognize these children’s genders create stigma, and these policies may have harmful consequences on mental health.

The story of same-sex marriage legalization, an issue that’s been around for decades, holds lessons in how policy can influence mental health. Before the U.S. Supreme Court’s 2015 decision to uphold the right of people of the same sex to marry, states had piecemeal policies, creating a natural experiment of sorts. In states that had recently legalized same-sex marriage, fewer teenagers attempted suicide, scientists reported February 20 in JAMA Pediatrics. In the states’ study, the drop was particularly steep for gay, lesbian and bisexual teens, health and social policy researcher Julia Raifman of Johns Hopkins Bloomberg School of Public Health and colleagues found. Although that study can’t determine the cause of the drop, Raifman suspects that the same-sex laws helped reduce negative stigma, and as a result, improved mental health. Mental health benefits have been documented in gay, lesbian and bisexual adults who are in legally recognized relationships. Marriage bans, on the other hand, had a negative effect.

Raifman says that the announcement from the Trump administration “suggests that transgender youth are different, negatively stereotypes transgender youth, gives transgender youth lesser rights, and allows for states or municipalities to use their power to enforce lesser rights.”

Gender is not a choice. Transgender children are quite clear on their gender identity, often from an early age. It’s easy to lose sight of the fact that behind these dreary statistics is someone’s daughter or son, a vulnerable child that the science clearly shows is at a greater risk of suffering simply because of how he or she was born.