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After the coldest night in south Florida in a decade, lizards were dropping out of palm trees, landing legs up. The scientists who raced to investigate the fallen reptiles have now found that, despite such graceless falls, some of these tropical, cold-blooded creatures are actually more resilient to cold than previously thought. The finding sheds light on how some species might respond to extreme weather events caused by human-caused climate change ( SN: 12/10/19 ). Although climate change is expected to include gradual warming globally, scientists think that extreme events such as heat waves, cold snaps, droughts and torrential downpours could also grow in number and strength over time. The idea for the new study was born after evolutionary ecologist James Stroud received a photo of a roughly 60-centimeter-long iguana prone on its back on a sidewalk from a friend in Key Biscayne, an island town south of Miami. The previous night, temperatures dropped to just under 4.4° Celsius (40°

Exactly how the coronavirus kills is a mystery. But part of the problem may be a partnership between just two immune system chemicals that triggers deadly organ damage. In mice, a combination of immune chemicals called TNF alpha and gamma interferon trips a domino chain of biochemical reactions that ultimately leads to three types of cell death , researchers report October 29 at bioRxiv.org. That wave of cell death further feeds an escalation of immune chemicals, known as a cytokine storm, that leads to more cell death and causes tissue and organ damage and failure. If the same process happens in people with severe COVID-19, the research points to several existing drugs that might help calm the cytokine storm and prevent severe disease or aid recovery. The preliminary results, however, have not yet been reviewed by other scientists. Study after study has found that people with severe COVID-19 have elevated levels of inflammation-stimulating chemicals called cytokines in their blood

Nearly 2,000 years ago, a cloud of scorching ash from Mount Vesuvius buried a young man as he lay on a wooden bed. That burning ash quickly cooled, turning some of his brain to glass. This confluence of events in A.D. 79 in the town of Herculaneum, which lay at the western base of the volcano, preserved the usually delicate neural tissue in a durable, glassy form. New scrutiny of this tissue has revealed signs of nerve cells with elaborate tendrils for sending and receiving messages, scientists report October 6 in PLOS ONE. That the young man once possessed these nerve cells, or neurons , is no surprise; human brains are packed with roughly 86 billion neurons ( SN: 8/7/19 ). But samples from ancient brains are sparse. Those that do exist have become a soaplike substance or mummified, says Pier Paolo Petrone, a biologist and forensic anthropologist at the University of Naples Federico II in Italy. But while studying the Herculaneum site, Petrone noticed something dark and shiny insid

Mysterious, now-extinct members of the human lineage called Denisovans lived at the roof of the world for possibly 100,000 years or more. Denisovan mitochondrial DNA extracted from sediment layers in Baishiya Karst Cave on the Tibetan Plateau indicates that these humanlike folk inhabited the high-altitude site roughly 100,000 years ago and again around 60,000 years ago, say geoarchaeologist Dongju Zhang of Lanzhou University, China, and her colleagues. These are the first examples of Denisovan DNA found outside of Siberia’s Denisova Cave ( SN: 12/16/1 9). Cave sediment possibly dating from 50,000 to 30,000 years ago also yielded Denisovan mitochondrial DNA, the scientists report in the Oct. 30 Science . If further research confirms that age estimate, it raises the likelihood that Denisovans survived on the Tibetan Plateau long enough to encounter the first humans to reach those heights as early as 40,000 years ago. In that case, ancient humans new to the region’s thin air may have

Some spiders wait for prey to come and tickle their web. But the ogre-faced spider ( Deinopis spinosa ) uses its sense of hearing to take its web to the prey. Hanging upside down, the spider weaves a rectangular web between its legs. When an insect flies behind the dangling arachnid, the spider swings backward, casting the web toward the prey. This behind-the-back hunting technique is one clue that the spiders can hear an unexpectedly wide range of sounds , researchers report online October 29 in Current Biology.  “A couple years ago, we didn’t really have a great idea that spiders could hear,” says Jay Stafstrom, a sensory ecologist at Cornell University. But now, he and his colleagues have looked at several spider species, and most can hear using specialized organs on their legs, he says. That includes jumping spiders, which respond to low frequencies ( SN: 10/15/16 ). Surprisingly, ogre-faced spiders can also hear fairly high frequencies, Stafstrom says. Stafstrom and colleagues

Octopus arms have minds of their own.  Each of these eight supple yet powerful limbs can explore the seafloor in search of prey, snatching crabs from hiding spots without direction from the octopus’ brain. But how each arm can tell what it’s grasping has remained a mystery.  Now, researchers have identified specialized cells not seen in other animals that allow octopuses to “taste” with their arms . Embedded in the suckers, these cells enable the arms to do double duty of touch and taste by detecting chemicals produced by many aquatic creatures. This may help an arm quickly distinguish food from rocks or poisonous prey, Harvard University molecular biologist Nicholas Bellono and his colleagues report online October 29 in Cell . The findings provide another clue about the unique evolutionary path octopuses have taken toward intelligence. Instead of being concentrated in the brain, two-thirds of the nerve cells in an octopus are distributed among the arms, allowing the flexible append

Earth is awash in gravitational waves. Over a six-month period, scientists captured a bounty of 39 sets of gravitational waves. The waves, which stretch and squeeze the fabric of spacetime, were caused by violent events such as the melding of two black holes into one. The haul was reported by scientists with the LIGO and Virgo experiments in several studies posted October 28 on a collaboration website and at arXiv.org. The addition brings the tally of known gravitational wave events to 50 . The bevy of data, which includes sightings from April to October 2019, suggests that scientists’ gravitational wave–spotting skills have leveled up. Before this round of searching, only 11 events had been detected in the years since the effort began in 2015. Improvements to the detectors — two that make up the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, in the United States, and another, Virgo, in Italy — have dramatically boosted the rate of gravitational wave sighting

It was one of those “big, if true” stories. In September, scientists reported that Venus’ atmosphere seems to be laced with phosphine, a possible sign of life. Now there’s increasing emphasis on the “if.” As scientists take fresh looks at the data behind the Venus announcement, and add other datasets to the mix, the original claim of inexplicable amounts of phosphine is being called into doubt. And that’s a good thing, many scientists say. “It’s exactly how science should work,” says planetary scientist Paul Byrne of North Carolina State University in Raleigh, who studies Venus but was not involved in any of the phosphine papers. “It’s too early to say one way or the other what this detection means for Venus.” Here’s a closer look at efforts to get from “if” to “true:” The big claim On September 14, astronomer Jane Greaves of Cardiff University in Wales and colleagues reported that they had seen signs of phosphine in Venus’ clouds using two different telescopes ( SN: 9/14/20 ). T

According to legend, Galileo dropped weights off of the Leaning Tower of Pisa, showing that gravity causes objects of different masses to fall with the same acceleration. In recent years, researchers have taken to replicating this test in a way that the Italian scientist probably never envisioned — by dropping atoms. A new study describes the most sensitive atom-drop test so far and shows that Galileo’s gravity experiment still holds up — even for individual atoms. Two different types of atoms had the same acceleration within about a part per trillion, or 0.0000000001 percent, physicists report in a paper in press in Physical Review Letters . Compared with a previous atom-drop test, the new research is a thousand times as sensitive. “It represents a leap forward,” says physicist Guglielmo Tino of the University of Florence, who was not involved with the new study. Researchers compared rubidium atoms of two different isotopes, atoms that contain different numbers of neutrons in thei

Mummified llamas stashed at a more than 500-year-old site on Peru’s southern coast offer the first direct glimpse of Inca ritual sacrifices of these animals. Colored strings made from the hair of llamas or closely related animals decorated five naturally mummified llamas found at an Inca administrative center called Tambo Viejo. Four of those llamas lay together beneath the floor of a large, rectangular structure, Lidio Valdez, an archaeologist at the University of Calgary in Canada, and his colleagues report in the December Antiquity . Scattered remains of at least three more llamas were found near the intact animals. Another llama, missing its head and possibly moved from another location, had been placed under the floor of a smaller building. Bones of hundreds of llamas had already been found at Tambo Viejo, consistent with Spanish historical accounts of mass llama sacrifices to appease various Inca deities. Those ceremonies involved the slaughter of llamas that were probably but

The time it takes for a single particle of light to pass through a hydrogen molecule is now the shortest duration ever measured. This interval was about 247 zeptoseconds , or trillionths of a billionth of a second, researchers report in the Oct. 16 Science . For comparison, there are as many zeptoseconds in one second as there are seconds in 2,500 times the age of the universe, which is about 13.8 billion years old. The new observation has allowed physicists to witness light-matter interactions at a whole new level of detail. The physicists shined particles of X-ray light on hydrogen molecules in a gas. As each light particle, or photon, crossed an H 2 molecule, it booted an electron from one hydrogen atom, then the other. Because electrons can exhibit wavelike behavior ( SN: 5/3/19 ), the two ejection events stirred up electron waves that spread out and merged — similar to ripples formed by a stone skipped twice over a pond. The overlapping crests and troughs of those waves create

Malaria parasites survive tough times by not being too clingy. During Africa’s dry season, when mosquitoes are scarce, malaria parasites have a hard time spreading to new hosts. So the parasites hide out in the human body by keeping the cells they infect from clinging to blood vessels, researchers report October 26 in Nature Medicine. This way, infected cells get removed from circulation and parasite levels in the body remain low, making people less sick and allowing the parasite to persist undetected.  Doctors have long observed that symptoms of malaria, a deadly mosquito-borne infection, tend to wane during the dry season, which runs from January to May. But the reason has been unclear. Keeping a low profile during dry months is a successful strategy for the parasite, says Martin Rono, a parasitologist at the KEMRI-Wellcome Trust in Kilifi, Kenya, who was not involved in the work. Knowing how malaria parasites persist without causing disease, until mosquitoes return to ferry the

Past observations have suggested that there’s water on the moon. New telescope observations conclude that those findings hold water. Spacecraft have seen evidence of water ice in permanently shadowed craters at the lunar poles ( SN: 5/9/16 ), as well as hints of water molecules on the sunlit surface ( SN: 9/23/09 ). But water sightings in sunlit regions have relied on detection of infrared light at a wavelength that could also be emitted by other hydroxyl compounds, which contain hydrogen and oxygen.  Now, the Stratospheric Observatory for Infrared Astronomy, or SOFIA, has detected an infrared signal unique to water near the lunar south pole , researchers report online October 26 in Nature Astronomy . “This is the first unambiguous detection of molecular water on the sunlit moon,” says study coauthor Casey Honniball, a lunar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “This shows that water is not just in the permanently shadowed regions — that there are other

On a day during the late Ice Age, a young adult or teen carrying a toddler hustled across a muddy flat where mammoths and giant sloths roamed. Now, over 10,000 years later, fossilized footprints reveal that possibly perilous journey. The tracks, found in New Mexico’s White Sands National Park, stretch for nearly 1.5 kilometers across the plain and back, making them the longest set ever found, researchers report in the Dec. 1 Quaternary Science Reviews. “The length of the trackway is really exceptional and give us a prolonged window into the behavior of the individuals,” says evolutionary biologist Kevin Hatala of Chatham University in Pittsburgh, who was not involved in the research. It evokes a personal and intimate connection with our ancestors, as many people today can relate to the feeling of holding a child in their arms, he says. Scientists stumbled across the find when, in 2018, they spied a continuous stretch of dark spots along what was once the shore of the ancient Lake O

There’s nothing Winifred Frick likes better than crawling through guano-filled caves and coming face-to-face with bats. As chief scientist of Bat Conservation International, she is on a mission to promote understanding of bats and protect imperiled species from extinction. For months, though, Frick has avoided research that would put her within spitting distance of bats. Her only projects to persist through the pandemic have been conducted from afar, like using acoustic monitors to eavesdrop on the animals’ squeaks and swooshes. In an era of COVID-19, that “hands-off” approach and other precautions are crucial to protect both bats and people , Frick, a biologist at the University of California, Santa Cruz, and over two dozen other scientists argue online September 3 in PLOS Pathogens . Why the call to action? SARS-CoV-2, the virus that causes COVID-19, likely originated in bats in China ( SN: 3/26/20 ). But neither it nor other coronaviruses belonging to the same genus — Betacoronav

An initial crop of clinical trials testing an anti-inflammatory drug against COVID-19 do not look promising. The best available evidence among these trials “doesn’t show that this drug is beneficial,” says Adarsh Bhimraj, an infectious diseases physician at the Cleveland Clinic, who was not involved in the research. The drug, tocilizumab, is a treatment for the painful joint swelling that occurs in rheumatoid arthritis and is also used to manage a dangerous side effect of the cancer treatment CAR-T cell therapy ( SN: 6/27/18 ). So clinical trials have been assessing whether tocilizumab might help COVID-19 patients by taming excessive inflammation as it does for these other two conditions. The drug works by blocking the activity of a protein called interleukin 6, which contributes to the immune system’s inflammatory response. High levels of this protein, known as a cytokine, are a harbinger of severe disease in COVID-19 patients, studies have found. Of the four clinical trials that

Only two dinosaur species are known to have had wings made out of stretched skin, like bats. But unlike bats, these dinos were capable of only limited gliding between trees, a new anatomical analysis suggests. That bat-winged gliding turned out to be a dead end along the path to the evolution of flight, researchers say. “They are a failed experiment,” says Alexander Dececchi, a paleontologist at Mount Marty University in Sioux Falls, S.D. Fliers with feathered wings, rather than membranous wings, begin to appear in the fossil record just a few million years after the bat-winged dinosaurs. Those feathered fliers may have outcompeted the gliders in their evolutionary niche, Dececchi and colleagues suggest October 22 in iScience . Yi qi and Ambopteryx longibrachium were crow-sized dinosaurs that lived about 160 million years ago ( SN: 4/29/15 ). They were distant cousins, both belonging to a bizarre group of dinosaurs known as scansoriopterygids. Unlike other scansoriopterygids, how

A type of bone tool generally thought to have been invented by Stone Age humans got its start among hominids that lived hundreds of thousands of years before Homo sapiens evolved, a new study concludes. A set of 52 previously excavated but little-studied animal bones from East Africa’s Olduvai Gorge includes the world’s oldest known barbed bone point , an implement probably crafted by now-extinct Homo erectus at least 800,000 years ago, researchers say. Made from a piece of a large animal’s rib, the artifact features three curved barbs and a carved tip, the team reports in the November Journal of Human Evolution . Among the Olduvai bones, biological anthropologist Michael Pante of Colorado State University in Fort Collins and colleagues identified five other tools from more than 800,000 years ago as probable choppers, hammering tools or hammering platforms. The previous oldest barbed bone points were from a central African site and dated to around 90,000 years ago ( SN: 4/29/95 )

An unforgiving environmental twist deserves at least some credit for the behavioral flexibility that has characterized the human species since our African origins around 300,000 years ago, a new study suggests. For hundreds of thousands of years in parts of East Africa, food and water supplies remained fairly stable. But new evidence shows that starting about 400,000 years ago, hominids and other ancient animals in the region faced a harsh environmental reckoning, says a team led by paleoanthropologist Rick Potts of the Smithsonian Institution in Washington, D.C. The climate began to fluctuate dramatically. Faults caused by volcanic eruptions fractured the landscape and reduced the size of lakes. Large animals died out and were replaced by smaller creatures with more diverse diets. These changes heralded a series of booms and busts in the resources hominids needed to survive, Potts and his colleagues report October 21 in Science Advances . Around that time, hominids at a site calle

NASA’s OSIRIS-REx spacecraft is a cosmic rock collector. Cheers erupted from mission control at 6:12 p.m. EDT on October 20 as scientists on Earth got word that the spacecraft had gently nudged a near-Earth asteroid called Bennu, and grabbed some of its rocks to return to Earth. “The spacecraft did everything it was supposed to do,” said mission principal investigator Dante Lauretta of the University of Arizona in Tucson on a NASA TV webcast. “I can’t believe we actually pulled this off.” OSIRIS-REx arrived at Bennu in December 2018, and spent almost two years making detailed maps of the 500-meter-wide asteroid’s surface features and composition ( SN: 10/8/20 ). Observations from Earth suggested Bennu should be smooth and sandy, but when OSIRIS-REx arrived, it found a treacherous, rocky landscape. The team selected a relatively smooth patch in a crater named Nightingale. The spot was not without hazards, though — the team was so worried about a particularly large rock nearby that t

The diabolical ironclad beetle is like a tiny tank on six legs. This insect’s rugged exoskeleton is so tough that the beetle can survive getting run over by cars, and many would-be predators don’t stand a chance of cracking one open. Phloeodes diabolicus is basically nature’s jawbreaker. Analyses of microscope images, 3-D printed models and computer simulations of the beetle’s armor have now revealed the secrets to its strength . Tightly interlocked and impact-absorbing structures that connect pieces of the beetle’s exoskeleton help it survive enormous crushing forces, researchers report in the Oct. 22 Nature . Those features could inspire new, sturdier designs for things such as body armor, buildings, bridges and vehicles. The diabolical ironclad beetle, which dwells in desert regions of western North America, has a distinctly hard-to-squish shape. “Unlike a stink beetle, or a Namibian beetle, which is more rounded … it’s low to the ground [and] it’s flat on top,” says David Kisai

Naked mole-rats — with their subterranean societies made up of a single breeding pair and an army of workers — seem like mammals trying their hardest to live like insects. Nearly 300 of the bald, bucktoothed, nearly blind rodents can scoot along a colony’s labyrinth of tunnels. New research suggests there’s brute power in those numbers: Like ants or termites, the mole-rats go to battle with rival colonies to conquer their lands.  Wild naked mole-rats ( Heterocephalus glaber ) will invade nearby colonies to expand their territory , sometimes abducting pups to incorporate them into their own ranks, researchers report September 28 in the Journal of Zoology . This behavior may put smaller, less cohesive colonies at a disadvantage, potentially supporting the evolution of bigger colonies.  Researchers stumbled across this phenomenon by accident while monitoring naked mole-rat colonies in Kenya’s Meru National Park. The team was studying the social structure of this extreme form of group l