By Kate Golembiewski Humans spend about 35 minutes every day chewing. That adds up to more than a full week out of every year. But that’s nothing compared to the time spent masticating by our cousins: Chimps chew for 4.5 hours a day, and orangutans clock 6.6 hours. The differences between our chewing habits and those of our closest relatives offer insights into human evolution. A study published Wednesday in the journal Science Advances explores how much energy people use while chewing, and how that may have guided — or been guided by — our gradual transformation into modern humans. Chewing, in addition to keeping us from choking, makes the energy and nutrients in food accessible to the digestive system. But the very act of chewing requires us to expend energy. Adaptations to teeth, jaws and muscles all play a part in how efficiently humans chew. Adam van Casteren, an author of the new study and a research associate at the University of Manchester in England, says that scientists haven’t delved too deeply into the energetic costs of chewing partly because compared with other things we do, such as walking or running, it’s a thin slice of the energy-use pie. But even comparatively small advantages can play a big role in evolution, and he wanted to find out if that might be the case with chewing. To measure the energy that goes into chewing, Dr. van Casteren and his colleagues outfitted study participants in the Netherlands with plastic hoods that look like “an astronaut’s helmet,” he said. The hoods were connected to tubes to measure oxygen and carbon dioxide from breathing. Because metabolic processes are fueled by oxygen and produce carbon dioxide, gas exchange can be a useful measure for how much energy something takes. The researchers then gave the subjects gum. The participants didn’t get the sugary kind, though; the gum bases they chewed were flavorless and odorless. Digestive systems respond to flavors and scents, so the researchers wanted to make sure they were only measuring the energy associated with chewing and not the energy of a stomach gearing up for a tasty meal. The test subjects chewed two pieces of gum, one hard and one soft, for 15 minutes each. The results surprised researchers. The softer gum raised the participants’ metabolic rates about 10 percent higher than when they were resting; the harder gum caused a 15 percent increase. © 2022 The New York Times Company

Keyword: Evolution
Link ID: 28440 - Posted: 08.20.2022

By Erin Garcia de Jesús Some mosquitoes have a near-foolproof thirst for human blood. Previous attempts to prevent the insects from tracking people down by blocking part of mosquitoes’ ability to smell have failed. A new study hints it’s because the bloodsuckers have built-in workarounds to ensure they can always smell us. For most animals, individual nerve cells in the olfactory system can detect just one type of odor. But Aedes aegypti mosquitoes’ nerve cells can each detect many smells, researchers report August 18 in Cell. That means if a cell were to lose the ability to detect one human odor, it still can pick up on other scents. The study provides the most detailed map yet of a mosquito’s sense of smell and suggests that concealing human aromas from the insects could be more complicated than researchers thought. Repellents that block mosquitoes from detecting human-associated scents could be especially tricky to make. “Maybe instead of trying to mask them from finding us, it would be better to find odorants that mosquitoes don’t like to smell,” says Anandasankar Ray, a neuroscientist at the University of California, Riverside who was not involved in the work. Such repellents may confuse or irritate the bloodsuckers and send them flying away (SN: 9/21/11; SN: 3/4/21). Effective repellents are a key tool to prevent mosquitoes from transmitting disease-causing viruses such as dengue and Zika (SN: 7/11/22). “Mosquitoes are responsible for more human deaths than any other creature,” says Olivia Goldman, a neurobiologist at Rockefeller University in New York City. “The better we understand them, the better that we can have these interventions.” © Society for Science & the Public 2000–2022.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28439 - Posted: 08.20.2022

By Carolyn Wilke Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. By day, jumping spiders hunt their prey, stalking and pouncing like cats. When the lights go down, these pea-sized predators hang out — and maybe their minds spin dreams. As they twitch their legs and move their eyes, Evarcha arcuata, a species of jumping spiders, show something reminiscent of rapid eye movement, or R.E.M., sleep, researchers report Monday in the Proceedings of the National Academy of Sciences. R.E.M. is the phase of sleep during which most human dreaming occurs. The study suggests that R.E.M. sleep may be more common than realized across animals, which may help untangle the mysteries of its purpose and evolution. To “look at R.E.M. sleep in something as distantly related to us as spiders is just utterly fascinating,” said Lauren Sumner-Rooney, a sensory biologist at the Leibniz Institute for Biodiversity and Evolution Research who wasn’t part of the new study. Daniela Roessler, a behavioral ecologist at the University of Konstanz in Germany and one of the study’s authors, was surprised when she noticed that jumping spiders sometimes dangle upside down during the night. Dr. Roessler started filming the resting arachnids and noticed other odd behaviors. “All of a sudden, they would make these crazy movements with the legs and start twitching. And it just reminded me immediately of a sleeping — not to say dreaming — cat or dog,” said Dr. Roessler. Such jerky movements in limbs are a marker of R.E.M. sleep, a state in which most of the body’s muscles go slack and the brain’s electrical activity mimics being awake. And then there’s the darting eyes, from which R.E.M. gets its name. But that’s tricky to spot it in animals with eyes that do not move, including spiders. However, part of a jumping spider’s eye does move. The acrobatic arachnids have eight eyes in total, and behind the lenses of their two biggest eyes are light-catching retinas that move to scan the environment. The arthropods’ exterior typically obscures these banana-shaped tubes, except when the spiders are babies and have translucent exoskeletons. So Dr. Roessler’s team looked for flitting retinas during rest in spiderlings younger than 10 days old. “It’s really clever,” said Paul Shaw, a neuroscientist at the Washington University School of Medicine. The researchers chose the right animal for this question, he added. © 2022 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28431 - Posted: 08.11.2022

By Oliver Whang Read this sentence aloud, if you’re able. As you do, a cascade of motion begins, forcing air from your lungs through two muscles, which vibrate, sculpting sound waves that pass through your mouth and into the world. These muscles are called vocal cords, or vocal folds, and their vibrations form the foundations of the human voice. They also speak to the emergence and evolution of human language. For several years, a team of scientists based mainly in Japan used imaging technology to study the physiology of the throats of 43 species of primates, from baboons and orangutans to macaques and chimpanzees, as well as humans. All the species but one had a similar anatomical structure: an extra set of protruding muscles, called vocal membranes or vocal lips, just above the vocal cords. The exception was Homo sapiens. The researchers also found that the presence of vocal lips destabilized the other primates’ voices, rendering their tone and timbre more chaotic and unpredictable. Animals with vocal lips have a more grating, less controlled baseline of communication, the study found; humans, lacking the extra membranes, can exchange softer, more stable sounds. The findings were published on Thursday in the journal Science. “It’s an interesting little nuance, this change to the human condition,” said Drew Rendall, a biologist at the University of New Brunswick who was not involved in the research. “The addition, if you want to think of it this way, is actually a subtraction.” That many primates have vocal lips has long been known, but their role in communication has not been entirely clear. In 1984, Sugio Hayama, a biologist at Kyoto University, videotaped the inside of a chimpanzee’s throat to study its reflexes under anesthesia. The video also happened to capture a moment when the chimp woke and began hollering, softly at first, then with more power. Decades later, Takeshi Nishimura, a former student of Dr. Hayama and now a biologist at Kyoto University and the principal investigator of the recent research, studied the footage with renewed interest. He found that the chimp’s vocal lips and vocal cords were vibrating together, which added a layer of mechanical complexity to the chimp’s voice that made it difficult to fine-tune. © 2022 The New York Times Company

Keyword: Language; Evolution
Link ID: 28426 - Posted: 08.11.2022

By Tim Vernimmen Just a few decades ago, even most biologists would have readily agreed that culture is a quintessentially human feature. Sure, they already knew there were dialects in birdsong, and good evidence that many birds largely learned these regional songs by copying other birds. They knew that some enterprising European songbirds called tits had learned how to open milk bottles by watching one another. Scientists had even reported that the practice of washing sweet potatoes in seawater had spread among the members of a Japanese colony of macaque monkeys. But these and similar behavioral differences between populations — ones that couldn’t easily be explained by differences in their genes or environment — seemed limited in scope. Compare that with human culture, which creates variation in nearly everything we do. In recent decades, however, scientists have learned that culture plays a much more pervasive role in the lives of nonhuman animals than anyone had imagined. “The whole field has absolutely exploded in discoveries in the present century,” says primatologist Andrew Whiten of the University of St. Andrews, Scotland, the author of a 2019 overview of cultural evolution in animals in the Annual Review of Ecology, Evolution, and Systematics. Whiten was one of the pioneers of the surge in animal culture research. In 1999, he oversaw an analysis in which primatologists published their findings from nearly four decades of studying wild chimpanzees, our closest living relatives. “We could show chimpanzees have multiple traditions affecting all different aspects of their lives,” he says — from foraging to tool use to courtship. Similar findings followed for several other apes and monkeys. © 2022 Annual Reviews

Keyword: Evolution; Learning & Memory
Link ID: 28417 - Posted: 08.03.2022

By Lesley Evans Ogden Hana aced her memory test. After viewing the contents of three identical boxes arrayed in an arc on the back deck of her home, the 3-year-old Cavalier King Charles spaniel had to remember which box held a treat — a task she quickly learned after just a few trials. Hana is part of a pack that has grown to nearly 40,000 pet dogs enrolled in a citizen science initiative known as the Dog Aging Project, founded in 2014. Understanding the biology of aging in companion dogs is one of two main goals of the project, says cofounder and codirector Matt Kaeberlein, a pathologist at the University of Washington in Seattle who focuses on aging. “The other is to do something about it.” Through veterinary records, DNA samples, health questionnaires and cognitive tests like Hana’s treat-finding challenge, the initiative of the University of Washington and Texas A&M University will track many aspects of dogs’ lives over time. Smaller subsets of the dogs, including Hana, will participate in more focused studies and more extensive evaluations. From all of this, scientists hope to spot patterns and find links between lifestyles and health from puppyhood through the golden years. The effort joins that of an earlier one: the Family Dog Project, spearheaded in the 1990s at Eötvös Loránd University (ELTE) in Budapest to study “the behavioral and cognitive aspects of the dog-human relationship,” with tens of thousands of canines participating through the decades. The two projects have begun collaborating across continents, and the scientists hope that such a large combined group of dogs can help them tease out genetic and environmental factors that affect how long dogs live, and how much of that time is spent in good health. © 2022 Annual Reviews

Keyword: Alzheimers; Development of the Brain
Link ID: 28411 - Posted: 07.30.2022

ByVirginia Morell We swat bees to avoid painful stings, but do they feel the pain we inflict? A new study suggests they do, a possible clue that they and other insects have sentience—the ability to be aware of their feelings. “It’s an impressive piece of work” with important implications, says Jonathan Birch, a philosopher and expert on animal sentience at the London School of Economics who was not involved with the paper. If the study holds up, he says, “the world contains far more sentient beings than we ever realized.” Previous research has shown honey bees and bumble bees are intelligent, innovative, creatures. They understand the concept of zero, can do simple math, and distinguish among human faces (and probably bee faces, too). They’re usually optimistic when successfully foraging, but can become depressed if momentarily trapped by a predatory spider. Even when a bee escapes a spider, “her demeanor changes; for days after, she’s scared of every flower,” says Lars Chittka, a cognitive scientist at Queen Mary University of London whose lab carried out that study as well as the new research. “They were experiencing an emotional state.” To find out whether these emotions include pain, Chittka and colleagues looked at one of the criteria commonly used for defining pain in animals: “motivational trade-offs.” People will endure the pain of a dentist’s drill for the longer term benefits of healthy teeth, for example. Similarly, hermit crabs will leave preferred shells to escape an electric shock only when given a particularly high jolt—an experiment that demonstrated crabs can tell the difference between weak and strong painful stimuli, and decide how much pain is worth enduring. That suggests crabs do feel pain and don’t simply respond reflexively to an unpleasant stimulus. Partly as a result of that study, crabs (and other crustaceans, including lobsters and crayfish) are recognized as sentient under U.K. law. © 2022 American Association for the Advancement of Science

Keyword: Pain & Touch; Evolution
Link ID: 28410 - Posted: 07.30.2022

By Laura Sanders A dog’s brain is wired for smell. Now, a new map shows just how extensive that wiring is. Powerful nerve connections link the dog nose to wide swaths of the brain, researchers report July 11 in the Journal of Neuroscience. One of these canine connections, a hefty link between areas that handle smell and vision, hasn’t been seen before in any species, including humans. The results offer a first-of-its-kind anatomical description of how dogs “see” the world with their noses. The new brain map is “awesome, foundational work,” says Eileen Jenkins, a retired army veterinarian and expert on working dogs. “To say that they have all these same connections that we have in humans, and then some more, it’s going to revolutionize how we understand cognition in dogs.” In some ways, the results aren’t surprising, says Pip Johnson, a veterinary radiologist and neuroimaging expert at Cornell University College of Veterinary Medicine. Dogs are superb sniffers. Their noses hold between 200 million and 1 billion odor molecule sensors, compared with the 5 million receptors estimated to dwell in a human nose. And dogs’ olfactory bulbs can be up to 30 times larger than people’s. But Johnson wanted to know how smell information wafts to brain regions beyond the obvious sniffing equipment. To build the map, Johnson and colleagues performed MRI scans on 20 mixed-breed dogs and three beagles. The subjects all had long noses and medium heads, and were all probably decent sniffers. Researchers then identified tracts of white matter fibers that carry signals between brain regions. A method called diffusion tensor imaging, which relies on the movement of water molecules along tissue, revealed the underlying tracts, which Johnson likens to the brain’s “road network.” © Society for Science & the Public 2000–2022.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28405 - Posted: 07.22.2022

By Sam Jones Watching a woodpecker repeatedly smash its face into a tree, it’s hard not to wonder how its brain stays intact. For years, the prevailing theory has been that structures in and around a woodpecker’s skull absorb the shocks created during pecking. “Blogs and information panels at zoos all present this as fact — that shock absorption is occurring in woodpeckers,” said Sam Van Wassenbergh, a biologist at the University of Antwerp. Woodpeckers have even inspired the engineering of shock-absorbing materials and gear, like football helmets. But now, after analyzing high-speed footage of woodpeckers in action, Dr. Van Wassenbergh and colleagues are challenging this long-held belief. They discovered that woodpeckers are not absorbing shocks during pecking and they likely aren’t being concussed by using their heads like hammers. Their work was published in Current Biology on Thursday. When a woodpecker slams its beak into a tree, it generates a shock. If something in a woodpecker’s skull were absorbing these shocks before they reached the brain — the way a car’s airbag absorbs shocks in an accident before they reach a passenger — then, on impact, a woodpecker’s head would decelerate more slowly compared with its beak. With this in mind, the researchers analyzed high-speed videos of six woodpeckers (three species, two birds each) hammering away into a tree. They tracked two points on each bird’s beak and one point on its eye to mark its brain’s location. They found that the eye decelerated at the same rate as the beak and, in a couple of cases, even more quickly, which meant that — at the very least — the woodpecker was not absorbing any shock during pecking. © 2022 The New York Times Company

Keyword: Brain Injury/Concussion; Evolution
Link ID: 28403 - Posted: 07.16.2022

By Gina Kolata It’s been known for more than half a century that many men lose their Y chromosomes as they age. But no one knew if it really mattered. The loss of Y could just be a sign of aging, like gray hair, with no clinical relevance. Now, though, researchers report that it can matter. Very much. A new study using male mice genetically engineered to lose their Y chromosomes provides insight. The paper, published on Thursday in the journal Science, found that when the Y chromosome was gone from blood cells in those mice, scar tissue built up in the heart, leading to heart failure and a shortened life span. Because there was a direct cause-and-effect relationship between the loss of Y and ailments of aging in the mice, the study bolsters the notion that the same thing can happen in human males. Researchers have documented an increase in risk for chronic diseases like heart disease and cancer related to loss of the Y chromosome in many studies over the years, including the new one, which used data from a large genetic study of the British population. The loss of Y could even account for some of the difference between the life spans of men and women, the authors of the Science study say. Other investigators not associated with the work were impressed. “The authors really nailed it here,” said Dr. Ross Levine, the deputy physician in chief for translational research at Memorial Sloan Kettering Cancer Center. “It’s super important work.” The inspiration for the new research came when Lars Forsberg, a researcher at Uppsala University, ran into a former professor on a bus in Uppsala, Sweden, in 2013. They began talking, and the professor told Dr. Forsberg that the Y chromosomes in fruit flies were more important than previously appreciated. Dr. Forsberg was intrigued. He had never paid much attention to the loss of Y chromosomes. Males have one X and one Y (females have two X’s), and nearly all the genes used by male cells are genes on the X. Dr. Forsberg had shared the common view that the Y chromosome was pretty much a genetic wasteland. © 2022 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28400 - Posted: 07.16.2022

By Erika Engelhaupt To Charles Darwin, nature had a certain order. And in that order, males always came out on top. They were the leaders, the innovators, the wooers and the doers. “The males of almost all animals have stronger passions than the females,” Darwin wrote in 1871. “The female, on the other hand, with the rarest of exceptions, is less eager.” The founder of evolutionary theory posited that throughout the animal kingdom, males are active, females are passive, and that’s pretty much that. Females, in sum, are boring. That’s poppycock, Lucy Cooke writes in her latest book, Bitch. This blinkered view of nature as a man’s world was conceived and promulgated by Victorian men who imposed their values and world view on animals, she says. Cooke, a documentary filmmaker and the author of The Truth About Animals and two children’s books (SN: 4/14/18, p. 26), has traveled the world and met scientists who are exposing the truth about the sexes. She takes readers on a wild ride as she observes the ridiculous mating rituals of sage grouse, searches for orca poop (to monitor sex hormones) and watches female lemurs boss around males. Through such adventures, Cooke learns that females are anything but boring. “Female animals are just as promiscuous, competitive, aggressive, dominant and dynamic as males,” she writes. That may not sound radical to today’s feminists, but in the field of evolutionary biology, such a pronouncement has long bordered on the heretical. Generations of biologists have focused on male behavior and physiology, on the assumption that females are little more than baby-making machines to be won over by the strongest, showiest males. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28372 - Posted: 06.15.2022

Philip Ball How do you spot an optimistic pig? This isn’t the setup for a punchline; the question is genuine, and in the answer lies much that is revealing about our attitudes to other minds – to minds, that is, that are not human. If the notion of an optimistic (or for that matter a pessimistic) pig sounds vaguely comical, it is because we scarcely know how to think about other minds except in relation to our own. Here is how you spot an optimistic pig: you train the pig to associate a particular sound – a note played on a glockenspiel, say – with a treat, such as an apple. When the note sounds, an apple falls through a hatch so the pig can eat it. But another sound – a dog-clicker, say – signals nothing so nice. If the pig approaches the hatch on hearing the clicker, all it gets is a plastic bag rustled in its face. What happens now if the pig hears neither of these sounds, but instead a squeak from a dog toy? An optimistic pig might think there’s a chance that this, too, signals delivery of an apple. A pessimistic pig figures it will just get the plastic bag treatment. But what makes a pig optimistic? In 2010, researchers at Newcastle University showed that pigs reared in a pleasant, stimulating environment, with room to roam, plenty of straw, and “pig toys” to explore, show the optimistic response to the squeak significantly more often than pigs raised in a small, bleak, boring enclosure. In other words, if you want an optimistic pig, you must treat it not as pork but as a being with a mind, deserving the resources for a cognitively rich life. We don’t, and probably never can, know what it feels like to be an optimistic pig. Objectively, there’s no reason to suppose that it feels like anything: that there is “something it is like” to be a pig, whether apparently happy or gloomy. Until rather recently, philosophers and scientists have been reluctant to grant a mind to any nonhuman entity. Feelings and emotions, hope and pain and a sense of self were deemed attributes that separated us from the rest of the living world. To René Descartes in the 17th century, and to behavioural psychologist BF Skinner in the 1950s, other animals were stimulus-response mechanisms that could be trained but lacked an inner life. To grant animals “minds” in any meaningful sense was to indulge a crude anthropomorphism that had no place in science. © 2022 Guardian News & Media Limited

Keyword: Evolution; Intelligence
Link ID: 28367 - Posted: 06.11.2022

Helena Horton Environment reporter Otters are able to learn from each other – but still prefer to solve some puzzles on their own, scientists have found. The semi-aquatic mammals are known to be very social and intelligent creatures, but a study by the University of Exeter has given new insight into their intellect. Researchers gave otters “puzzle boxes”, some of which contained familiar food, while others held unfamiliar natural prey – shore crab and blue mussels, which are protected by hard outer shells. For the familiar food – meatballs, a favourite with the Asian short-clawed otters in the study – the scientists had five different types of boxes, and the method to extract the food changed in each version, for example pulling a tab or opening a flap. The unfamiliar food presented additional problems because the otters did not know if the crab and mussels were safe to eat and had no experience of getting them out of their shells. In order to decide whether food was safe and desirable to eat, the otters, which live at Newquay zoo and the Tamar Otter and Wildlife Centre, watched intently as their companions inspected what was in the boxes and copied if the other otters sampled the treats. However, they spent more time trying to figure out how to remove the meat from the shells on their own and relied less on the actions of their companions. Of the 20 otters in the study, 11 managed to extract the meat from all three types of natural prey. © 2022 Guardian News & Media Limited

Keyword: Learning & Memory; Evolution
Link ID: 28360 - Posted: 06.09.2022

By Jack Tamisiea Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. Since the days of Charles Darwin, the long necks of giraffes have been a textbook example of evolution. The theory goes that as giraffe ancestors competed for food, those with longer necks were able to reach higher leaves, getting a leg — or neck — up over shorter animals. But a bizarre prehistoric giraffe relative reveals that fighting may have driven early neck evolution in addition to foraging. In a study published Thursday in Science, a team of paleontologists described Discokeryx xiezhi, a giraffe ancestor, as having helmet-like headgear and bulky neck vertebrae. Discokeryx was adapted to absorb and deliver skull-cracking collisions to woo mates and vanquish rivals. “It shows that giraffe evolution is not just elongating the neck,” said Jin Meng, a paleontologist at the American Museum of Natural History and co-author of the new study. “Discokeryx goes in a totally different direction.” Dr. Meng and his colleagues discovered the fossils in an outcrop of rock in northwestern China called the Junggar Basin. Around 17 million years ago, this area was an expanse of savannas and forests home to an array of large mammals like shovel-tusked elephants, short-horned rhinoceroses and burly bear dogs. While exploring this bonebed in 1996, Dr. Meng stumbled across a hunk of skull. He could tell it was a mammalian braincase, but the top was flattened like an iron press. Without more of the animal’s skeleton, Dr. Meng and his colleagues referred to it as the “strange beast.” © 2022 The New York Times Company

Keyword: Evolution; Aggression
Link ID: 28350 - Posted: 06.04.2022

ByVirginia Morell Babies don’t babble to sound cute—they’re taking their first steps on the path to learning language. Now, a study shows parrot chicks do the same. Although the behavior has been seen in songbirds and two mammalian species, finding it in these birds is important, experts say, as they may provide the best nonhuman model for studying how we begin to learn language. The find is “exciting,” says Irene Pepperberg, a comparative psychologist at Hunter College not involved with the work. Pepperberg herself discovered something like babbling in a famed African gray parrot named Alex, which she studied for more than 30 years. By unearthing the same thing in another parrot species and in the wild, she says, the team has shown this ability is widespread in the birds. In this study, the scientists focused on green-rumped parrotlets (Forpus passerinus)—a smaller species than Alex, found from Venezuela to Brazil. The team investigated a population at Venezuela’s Hato Masaguaral research center, where scientists maintain more than 100 artificial nesting boxes. Like other parrots, songbirds, and humans (and a few other mammal species), parrotlets are vocal learners. They master their calls by listening and mimicking what they hear. The chicks in the new study started to babble at 21 days, according to camcorders installed in a dozen of their nests. They increased the complexity of their sounds dramatically over the next week, the scientists report today in the Proceedings of the Royal Society B. The baby birds uttered strings of soft peeps, clicks, and grrs, but they weren’t communicating with their siblings or parents, says lead author Rory Eggleston, a Ph.D. student at Utah State University. Rather, like a human infant babbling quietly in their crib, a parrotlet chick made the sounds alone (see video). Indeed, most chicks started their babbling bouts when their siblings were asleep, often doing so without even opening their beaks, says Eggleston, who spent hours analyzing videos of the birds. © 2022 American Association for the Advancement of Science.

Keyword: Language; Animal Communication
Link ID: 28343 - Posted: 06.01.2022

By Laura Sanders Punishing headbutts damage the brains of musk oxen. That observation, made for the first time and reported May 17 in Acta Neuropathologica, suggests that a life full of bell-ringing clashes is not without consequences, even in animals built to bash. Although a musk ox looks like a dirty dust mop on four tiny hooves, it’s formidable. When charging, it can reach speeds up to 60 kilometers an hour before ramming its head directly into an oncoming head. People expected that musk oxen brains could withstand these merciless forces largely unscathed, “that they were magically perfect,” says Nicole Ackermans of the Icahn School of Medicine at Mount Sinai in New York City. “No one actually checked.” In fact, the brains of three wild musk oxen (two females and one male) showed signs of extensive damage, Ackermans and her colleagues found. The damage was similar to what’s seen in people with chronic traumatic encephalopathy, a disorder known to be caused by repetitive head hits (SN: 12/13/17). In the musk ox brains, a form of a protein called tau had accumulated in patterns that suggested brain bashing was to blame. In an unexpected twist, the brains of the females, who hit heads less frequently than males, were worse off than the male’s. The male body, with its heavier skull, stronger neck muscles and forehead fat pads, may cushion the blows to the brain, the researchers suspect. The results may highlight an evolutionary balancing act; the animals can endure just enough brain damage to allow them to survive and procreate. High-level brainwork may not matter much, Ackermans says. “Their day-to-day life is not super complicated.” © Society for Science & the Public 2000–2022.

Keyword: Brain Injury/Concussion; Evolution
Link ID: 28341 - Posted: 05.28.2022

By Tess Joosse The mere sight of another person yawning causes many of us to open our mouths wide in mimicry. And we’re not alone—other social animals, such aschimpanzees and lions, can also catch so-called contagious yawns. It’s likely that all vertebrates yawn spontaneously to regulate inner body processes. Yawning probably arose with the evolution of jawed fishes 400 million or so years ago, says Andrew Gallup, an evolutionary biologist at State University of New York Polytechnic Institute who has spent years trying to figure out why we yawn. In a paper published this month in Animal Behavior, he reports some evidence for how contagious yawns might have evolved to keep us safe. Science chatted with Gallup about why yawning is ubiquitous—and useful. This interview has been edited for clarity and length. Q: First, let’s address a long-standing myth: Does yawning increase blood oxygen levels? A: No. Despite continued belief, research has explicitly tested that hypothesis and the results have concluded that breathing and yawning are controlled by different mechanisms. For example, there are really interesting cases of yawning in marine mammals, where the yawning occurs while the animal is submerged underwater and therefore not breathing. Q: So what does yawning actually do to the body? A: Yawning is a rather complex reflex. It’s triggered under a variety of contexts and neurophysiological changes. It primarily occurs during periods of state change, commonly following transitions of sleeping and waking. There’s research that also suggests that yawns are initiated alongside increases in cortical arousal, so yawns themselves may function to promote alertness. And there’s a growing body of research that suggests that yawning is triggered by rises in brain temperature. I’ve conducted a number of studies testing this in humans, nonhuman mammals, and even birds. © 2022 American Association for the Advancement of Science.

Keyword: Emotions; Evolution
Link ID: 28337 - Posted: 05.25.2022

By Veronique Greenwood Lovebirds, small parrots with vibrant rainbow plumage and cheeky personalities, are popular pets. They swing from ropes, cuddle with companions and race for treats in a waddling gait with all the urgency of toddlers who spot a cookie. But, along with other parrots, they also do something strange: They use their faces to climb walls. Give these birds a vertical surface to clamber up, and they cycle between left foot, right foot and beak as if their mouths were another limb. In fact, a new analysis of the forces climbing lovebirds exert reveals that this is precisely what they are doing. Somehow, a team of scientists wrote in the journal Proceedings of the Royal Society B on Wednesday, the birds and perhaps other parrot species have repurposed the muscles in their necks and heads so they can walk on their beaks, using them the way rock climbers use their arms. Climbing with a beak as a third limb is peculiar because third limbs generally are not something life on Earth is capable of producing, said Michael Granatosky, an assistant professor of anatomy at the New York Institute of Technology and an author of the new paper. “There is this very deep, deep set aspect of our biology that everything is bilateral” in much of the animal kingdom, he said. The situation makes it developmentally unlikely to grow an odd numbers of limbs for walking. Some animals have developed workarounds. Kangaroos use their tails as a fifth limb when hopping slowly, pushing off from the ground with their posteriors the same way they push with their feet. To see if parrots were using their beaks in a similar way, Dr. Granatosky and a graduate student, Melody Young, as well as their colleagues brought six rosy-faced lovebirds from a pet store into the lab. They had the birds climb up a surface that was fitted with a sensor to keep track of how much force they were exerting and in what directions. The scientists found that the propulsive force the birds applied through their beaks was similar to what they provided with their legs. What had started as a way to eat had transformed into a way to walk, with beaks as powerful as their limbs. © 2022 The New York Times Company

Keyword: Evolution
Link ID: 28336 - Posted: 05.25.2022

By Anna Gibbs Cradled inside the hushed world of the womb, fetuses might be preparing to come out howling. In the same way newborn humans can cry as soon as they’re born, common marmoset monkeys (Callithrix jacchus) produce contact calls to seek attention from their caregivers. Those vocalizations are not improv, researchers report in a preprint posted April 14 at bioRxiv. Ultrasound imaging of marmoset fetuses reveals that their mouths are already mimicking the distinctive pattern of movements used to emit their first calls, long before the production of sound. Early behaviors in infants are commonly described as “innate” or “hard-wired,” but a team at Princeton University wondered how exactly those behaviors develop. How does a baby know how to cry as soon as it’s born? The secret may lie in what’s happening before birth. “People tend to ignore the fetal period,” says Darshana Narayanan, a behavioral neuroscientist who did the research while at Princeton University. “They just think that it’s like the baby’s just vegetating and waiting to be born…. [But] that’s where many things begin.” Research shows, for instance, that chicks inside their eggs are already learning to identify their species’ call (SN: 9/16/21). “So much is developing so much earlier in development than we previously thought,” says developmental psychobiologist Samantha Carouso-Peck, executive director of Grassland Bird Trust in Fort Edward, N.Y., who was not involved in the research. But, she says, “we really haven’t looked much at all at the production side of this. Most of what we know is the auditory side.” Carouso-Peck studies vocal learning in songbirds and how it applies to how humans acquire language. © Society for Science & the Public 2000–2022.

Keyword: Animal Communication; Language
Link ID: 28325 - Posted: 05.11.2022

Freda Kreier Some bats can imitate the sound of buzzing hornets to scare off owls, researchers say. The discovery is the first documented case of a mammal mimicking an insect to deter predators. Many animals copy other creatures in a bid to make themselves seem less palatable to predators. Most of these imitations are visual. North America’s non-venomous scarlet kingsnake (Lampropeltis elapsoides), for instance, has evolved to have similar colour-coding to the decidedly more dangerous eastern coral snake (Micrurus fulvius). Now, a study comparing the behaviour of owls exposed to insect and bat noises suggests that greater mouse-eared bats (Myotis myotis) might be among the few animals to have weaponized another species’ sound, says co-author Danilo Russo, an animal ecologist at the University of Naples Federico II in Italy. “When we think of mimicry, the first thing that comes to mind is colour, but in this case, it is sound that plays a crucial role,” he adds. The research was published on 9 May in Current Biology1. Because they are nocturnal and have poor eyesight, most bats rely on echolocation to find their way around, and communicate using a wide array of other noises. Russo first noticed that the distress call of the greater mouse-eared bat sounded like the buzzing of bees or hornets while he was catching the bats for a different research project. To investigate whether other animals might make the same connection, Russo and his colleagues compared the sound structure of buzzing by the European hornet (Vespa crabro) to that of the bat’s distress call. At most frequencies, the two sounds were not dramatically similar, but they were when the bat’s call was stripped down to include only frequencies that owls — one of the animal’s main predators — are able to hear. This suggests that the distress call as heard by owls strongly resembles the buzzing of a hornet, Russo says, so it could fool predators. © 2022 Springer Nature Limited

Keyword: Hearing; Evolution
Link ID: 28324 - Posted: 05.11.2022