Chapter 6. Evolution of the Brain and Behavior

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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

Erin Spencer The octopus is one of the coolest animals in the sea. For starters, they are invertebrates. That means they don’t have backbones like humans, lions, turtles and birds. Understand new developments in science, health and technology, each week That may sound unusual, but actually, nearly all animals on Earth are invertebrates – about 97%. Octopuses are a specific type of invertebrate called cephalopods. The name means “head-feet” because the arms of cephalopods surround their heads. Other types of cephalopods include squid, nautiloids and cuttlefish. As marine ecologists, we conduct research on how ocean animals interact with each other and their environments. We’ve mostly studied fish, from lionfish to sharks, but we have to confess we remain captivated by octopuses. What octopuses eat depends on what species they are and where they live. Their prey includes gastropods, like snails and sea slugs; bivalves, like clams and mussels; crustaceans, like lobsters and crabs; and fish. To catch their food, octopuses use lots of strategies and tricks. Some octopuses wrap their arms – not tentacles – around prey to pull them close. Some use their hard beak to drill into the shells of clams. All octopuses are venomous; they inject toxins into their prey to overpower and kill them. There are about 300 species of octopus, and they’re found in every ocean in the world, even in the frigid waters around Antarctica. A special substance in their blood helps those cold-water species get oxygen. It also turns their blood blue. © 2010–2022, The Conversation US, Inc.

Keyword: Evolution; Intelligence
Link ID: 28321 - Posted: 05.11.2022

By Elizabeth Preston On dry nights, the San hunter-gatherers of Namibia often sleep under the stars. They have no electric lights or new Netflix releases keeping them awake. Yet when they rise in the morning, they haven’t gotten any more hours of sleep than a typical Western city-dweller who stayed up doom-scrolling on their smartphone. Research has shown that people in non-industrial societies — the closest thing to the kind of setting our species evolved in — average less than seven hours a night, says evolutionary anthropologist David Samson at the University of Toronto Mississauga. That’s a surprising number when you consider our closest animal relatives. Humans sleep less than any ape, monkey or lemur that scientists have studied. Chimps sleep around 9.5 hours out of every 24. Cotton-top tamarins sleep around 13. Three-striped night monkeys are technically nocturnal, though really, they’re hardly ever awake — they sleep for 17 hours a day. Samson calls this discrepancy the human sleep paradox. “How is this possible, that we’re sleeping the least out of any primate?” he says. Sleep is known to be important for our memory, immune function and other aspects of health. A predictive model of primate sleep based on factors such as body mass, brain size and diet concluded that humans ought to sleep about 9.5 hours out of every 24, not seven. “Something weird is going on,” Samson says. Research by Samson and others in primates and non-industrial human populations has revealed the various ways that human sleep is unusual. We spend fewer hours asleep than our nearest relatives, and more of our night in the phase of sleep known as rapid eye movement, or REM. The reasons for our strange sleep habits are still up for debate but can likely be found in the story of how we became human. Graph shows average time spent sleep of different primate species. Humans sleep the least at seven hours per night; the three-striped night monkey sleeps the most at nearly 17 hours. © 2022 Annual Reviews

Keyword: Sleep; Evolution
Link ID: 28310 - Posted: 04.30.2022

By Lisa Feldman Barrett Do your facial movements broadcast your emotions to other people? If you think the answer is yes, think again. This question is under contentious debate. Some experts maintain that people around the world make specific, recognizable faces that express certain emotions, such as smiling in happiness, scowling in anger and gasping with widened eyes in fear. They point to hundreds of studies that appear to demonstrate that smiles, frowns, and so on are universal facial expressions of emotion. They also often cite Charles Darwin’s 1872 book The Expression of the Emotions in Man and Animals to support the claim that universal expressions evolved by natural selection. Other scientists point to a mountain of counterevidence showing that facial movements during emotions vary too widely to be universal beacons of emotional meaning. People may smile in hatred when plotting their enemy’s downfall and scowl in delight when they hear a bad pun. In Melanesian culture, a wide-eyed gasping face is a symbol of aggression, not fear. These experts say the alleged universal expressions just represent cultural stereotypes. To be clear, both sides in the debate acknowledge that facial movements vary for a given emotion; the disagreement is about whether there is enough uniformity to detect what someone is feeling. This debate is not just academic; the outcome has serious consequences. Today you can be turned down for a job because a so-called emotion-reading system watching you on camera applied artificial intelligence to evaluate your facial movements unfavorably during an interview. In a U.S. court of law, a judge or jury may sometimes hand down a harsher sentence, even death, if they think a defendant’s face showed a lack of remorse. Children in preschools across the country are taught to recognize smiles as happiness, scowls as anger and other expressive stereotypes from books, games and posters of disembodied faces. And for children on the autism spectrum, some of whom have difficulty perceiving emotion in others, these teachings do not translate to better communication. © 2022 Scientific American,

Keyword: Emotions; Evolution
Link ID: 28306 - Posted: 04.30.2022

Natalia Mesa Cravings for sugary treats and other “wants” in humans are driven by the activity of dopamine-producing cells in our mesolimbic system. Experimental research now suggests that a similar system might also exist in honeybees (Apis mellifera), spurring them to “want” to search for sources of nectar. In a study published today (April 28) in Science, researchers found that bees’ dopamine levels were elevated during the search for food and dropped once the food was consumed. Dopamine may also help trigger a hedonic, or pleasant, “memory” of the sugary treat, the researchers say, as dopamine levels rose again when foragers danced to tell other foragers about the foods’ locations. “The whole story is new. To show that there is a wanting system in insects is generally new,” says study coauthor Martin Giurfa, a neuroscientist at Paul Sabatier University in Toulouse, France. “Bees are truly amazing.” In both humans and invertebrates, dopamine is known to be involved in learning and reward. Giurfa and his team have been studying the neurotransmitter in bees, and several years ago, they characterized many of the neural pathways that involved dopamine. “We found so many so diverse pathways that we said, ‘There might be more than just representing reinforcement, representing punishment, representing reward.’” He began to look for other roles dopamine might play in honeybee behavior. bee next to pink flower © 1986–2022 The Scientist.

Keyword: Drug Abuse; Evolution
Link ID: 28305 - Posted: 04.30.2022

By Sharon Oosthoek Despite their excellent vision, one city-dwelling colony of fruit bats echolocates during broad daylight — completely contrary to what experts expected. A group of Egyptian fruit bats (Rousettus aegyptiacus) in downtown Tel Aviv uses sound to navigate in the middle of the day, researchers report in the April 11 Current Biology. The finding greatly extends the hours during which bats from this colony echolocate. A few years ago, some team members had noticed bats clicking while they flew under low-light conditions. The midday sound-off seems to help the bats forage and navigate, even though they can see just fine. Bats that are active during the day are unusual. Out of the more than 1,400 species, roughly 10 are diurnal. What’s more, most diurnal bats don’t use echolocation during the day, relying instead on their vision to forage and avoid obstacles. They save echolocation for dim light or dark conditions. So that’s why, two years ago, a group of Tel Aviv researchers were surprised when they noticed a bat smiling during the day. They were looking over photos from their latest study of Egyptian fruit bats when they noticed one with its mouth slightly parted and upturned. “When an Egyptian fruit bat is smiling, he’s echolocating — he’s producing clicks with his tongue and his mouth is open,” says Ofri Eitan, a bat researcher at Tel Aviv University. “But this was during the day, and these bats see really well.” When Eitan and his colleagues looked through other photos — thousands of them — many showed smiling bats in broad daylight. The team showed in 2015 that the diurnal Egyptian fruit bats do use echolocation outdoors under various low light conditions, at least occasionally. But the researchers hadn’t looked at whether the bats were echolocating during midday hours when light levels are highest. © Society for Science & the Public 2000–2022.

Keyword: Hearing; Evolution
Link ID: 28286 - Posted: 04.16.2022

By Jake Buehler Earthen piles built by a chicken-like bird in Australia aren’t just egg incubators — they may also be crucial for the distribution of key nutrients throughout the ecosystem. In the dry woodlands of South Australia, sandy mounds rise between patches of many-stemmed “mallee” eucalyptus trees. These monuments — big enough to smother a parking space — are nests, painstakingly constructed by the malleefowl bird. By inadvertently engineering a patchwork of nutrients and churned soil, the industrious malleefowl may be molding surrounding plant and soil communities and even blunting the spread of fire, researchers report March 27 in the Journal of Ecology. Such ecosystem impacts suggest malleefowl conservation could benefit many species, says Heather Neilly, an ecologist at the Australian Landscape Trust in Calperum Station. The species is currently listed as “vulnerable” and declining by the International Union for Conservation of Nature. Some animals — termed “ecosystem engineers” — produce habitats for other species by shaping the environment around them. Beavers build dams that create homes for pond-dwelling lifeforms. In deserts, owls and giant lizards support plant and animal life with their burrows (SN: 10/8/19; SN: 1/19/21). “In Australia in particular, the focus has largely been on our array of digging mammals,” Neilly says. But malleefowl (Leipoa ocellata) — found throughout western and southern Australia — also perturb the soil. They and their close relatives are “megapodes,” a group of fowl native to Australasia and the South Pacific that have the unusual habit of incubating their eggs much like alligators do: in a massive pile of rotting compost. Heat from the decaying vegetation — locked in with an insulating sand layer on top — regulates the eggs’ temperature, and the young scratch their way to the surface upon hatching. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28280 - Posted: 04.13.2022

By Annie Roth and Hisako Ueno The reign of Japan’s monkey queen has just begun. Last year, Yakei, a 9-year-old female Japanese macaque, fought several other macaques, including her own mother, to become the alpha of her troop. That made Yakei the first known female troop leader in the history of Takasakiyama Natural Zoological Garden in Southern Japan, which was established in 1952 and is home to over 1,000 macaques. But during her first breeding season as queen, which began in November 2021 and concluded in March 2022, a messy love triangle threatened to weaken her grip on power. According to officials at the park, the macaque that Yakei showed interest in mating with, a 15-year-old male named Goro, rejected her advances despite their coupling during a previous breeding season. Meanwhile, an 18-year-old macaque named Luffy did his best to woo Yakei, much to her displeasure. Japanese macaques are polyamorous and scientists were worried that Yakei would not be able to maintain her status while pursuing and rejecting potential mates. Tensions run high during breeding season, and a challenge from a spurned male could easily rob Yakei, an average-sized female, of her rank. Yakei rose to power by defeating her troop’s alpha male, but he was elderly and less formidable than the average young male. Fortunately for Yakei, no other macaques attempted to usurp her throne this season and the queen remained the troop’s alpha at the end of March, according to reserve officials. Her continued rule has surprised scientists and given them an opportunity to observe how macaque society functions under a matriarchy. Despite having to maintain her supremacy, Yakei managed to have a successful breeding season. After Goro gave her the cold shoulder, she spent many weeks playing the field, expressing interest in no fewer than five males. Among these males was Chris, a male ranked 10th in the troop, and Shikao, who holds the rank just below Chris. But the only male the reserve is sure she mated with was Maruo. Maruo, Yakei’s mate. © 2022 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 28279 - Posted: 04.13.2022

By Alla Katsnelson A dog gives a protective bark, sensing a nearby stranger. A cat slinks by disdainfully, ignoring anyone and everyone. A cow moos in contentment, chewing its cud. At least, that’s what we may think animals feel when they act the way they do. We take our own lived experiences and fill in gaps with our imaginations to better understand and relate to the animals we encounter. Often, our assumptions are wrong. Take horse play, for example. Many people assume that these muscular, majestic animals are roughhousing just for the fun of it. But in the wild, adult horses rarely play. When we see them play in captivity, it isn’t necessarily a good sign, says Martine Hausberger, an animal scientist at CNRS at the University of Rennes in France. Hausberger, who raises horses on her farm in Brittany, began studying horse welfare about three decades ago, after observing that people who keep horses often misjudge cues about the animals’ behavior. Adult horses that play are often ones that have been restrained, Hausberger says. Play seems to discharge the stress from that restriction. “When they have the opportunity, they may exhibit play, and at that precise moment they may be happier,” she says. But “animals that are feeling well all the time don’t need this to get rid of the stress.” Scientists studying animal behavior and animal welfare are making important strides in understanding how the creatures we share our planet with experience the world. “In the last decade or two, people have gotten bolder and more creative in terms of asking what animals’ emotional states are,” explains Georgia Mason, a behavioral biologist and animal welfare scientist at the University of Guelph in Canada. They’re finding thought-provoking answers amid a wide array of animals. © Society for Science & the Public 2000–2022.

Keyword: Emotions; Evolution
Link ID: 28276 - Posted: 04.09.2022

ByTess Joosse My dog Leo clearly knows the difference between my voice and the barks of the beagle next door. When I speak, he looks at me with love; when our canine neighbor makes his mind known, Leo barks back with disdain. A new study backs up what I and my fellow dog owners have long suspected: Dogs’ brains process human and canine vocalizations differently, suggesting they evolved to recognize our voices from their own. “The fact that dogs use auditory information alone to distinguish between human and dog sound is significant,” says Jeffrey Katz, a cognitive neuroscientist at Auburn University who is not involved with the work. Previous research has found that dogs can match human voices with expressions. When played an audio clip of a lady laughing, for example, they’ll often look at a photo of a smiling woman. But how exactly the canine brain processes sounds isn’t clear. MRI has shown certain regions of the dog brain are more active when a pup hears another dog whine or bark. But those images can’t reveal exactly when neurons in the brain are firing, and whether they fire differently in response to different noises. So in the new study, Anna Bálint, a canine neuroscientist at Eötvös Loránd University, turned to an electroencephalogram, which can measure individual brain waves. She and her colleagues recruited 17 family dogs, including several border collies, golden retrievers, and a German shepherd, that were previously taught to lie still for several minutes at a time. The scientists attached electrodes to each dog’s head to record its brain response—not an easy task, it turns out. Unlike humans’ bony noggins, dog heads have lots of muscles that can obstruct a clear readout, Bálint says. © 2022 American Association for the Advancement of Science.

Keyword: Language; Animal Communication
Link ID: 28270 - Posted: 04.06.2022

By Carolyn Gramling Modern mammals are known for their big brains. But new analyses of mammal skulls from creatures that lived shortly after the dinosaur mass extinction shows that those brains weren’t always a foregone conclusion. For at least 10 million years after the dinosaurs disappeared, mammals got a lot brawnier but not brainier, researchers report in the April 1 Science. That bucks conventional wisdom, to put it mildly. “I thought, it’s not possible, there must be something that I did wrong,” says Ornella Bertrand, a mammal paleontologist at the University of Edinburgh. “It really threw me off. How am I going to explain that they were not smart?” Modern mammals have the largest brains in the animal kingdom relative to their body size. How and when that brain evolution happened is a mystery. One idea has been that the disappearance of all nonbird dinosaurs following an asteroid impact at the end of the Mesozoic Era 66 million years ago left a vacuum for mammals to fill (SN: 1/25/17). Recent discoveries of fossils dating to the Paleocene — the immediately post-extinction epoch spanning 66 million to 56 million years ago — does reveal a flourishing menagerie of weird and wonderful mammal species, many much bigger than their Mesozoic predecessors. It was the dawn of the Age of Mammals. Before those fossil finds, the prevailing wisdom was that in the wake of the mass dino extinction, mammals’ brains most likely grew apace with their bodies, everything increasing together like an expanding balloon, Bertrand says. But those discoveries of Paleocene fossil troves in Colorado and New Mexico, as well as reexaminations of fossils previously found in France, are now unraveling that story, by offering scientists the chance to actually measure the size of mammals’ brains over time. © Society for Science & the Public 2000–2022.

Keyword: Evolution
Link ID: 28266 - Posted: 04.02.2022

Dolphins are known to use physical contact like petting and rubbing to bond with their closest allies. But for more distant contacts, male dolphins bond by trading whistles instead. KELSEY SNELL, HOST: You know those friends who live far away, but you still stay in touch? You can't really hug, so you call or text them instead. Well, dolphins do something sort of similar. AILSA CHANG, HOST: That, my friends, is whistling. A new study found that the male bottlenose dolphins in Western Australia whistle to the other male dolphins they don't have strong bonds with. SNELL: University of Bristol marine biologist Emma Chereskin is the lead author of the study. She explains that male bottlenose dolphins have an alliance structure. They have their closest circle where the bonds are strong. EMMA CHERESKIN: They often use physical touch, so rubbing their fins together, swimming side by side. CHANG: Then there is another circle where the bonds are weaker and they don't use as much physical touch, but they do whistle to identify themselves and to keep alliances intact. In other words, they bond at a distance. Sound familiar? SNELL: That was a whistle exchange between three dolphins. The researchers gave them names - Kooks (ph), Spirit and Guppy. CHERESKIN: They're saying, hi, I'm Kooks. I'm right here. And then Spirit would reply, hi, I'm Spirit. I'm also right here. And then Guppy gets in on it towards the end. He's saying, hi, I'm Guppy. I'm also here. CHANG: The study tests the social bonding hypothesis of Robin Dunbar. He proposed that animal vocalizations evolved as a form of vocal grooming to replace physical grooming. Karl Berg from the University of Texas Rio Grande Valley says this study advances that hypothesis. KARL BERG: These dolphin groups can be in really large groups in the dark ocean where visual communication isn't going to be possible. It makes sense that this vocal communication system is very important to them. © 2022 npr

Keyword: Animal Communication; Evolution
Link ID: 28262 - Posted: 04.02.2022

By Bruce Bower Human language, in its many current forms, may owe an evolutionary debt to our distant ape ancestors who sounded off in groups of scattered individuals. Wild orangutans’ social worlds mold how they communicate vocally, much as local communities shape the way people speak, researchers report March 21 in Nature Ecology & Evolution. This finding suggests that social forces began engineering an expanding inventory of communication sounds among ancient ancestors of apes and humans, laying a foundation for the evolution of language, say evolutionary psychologist Adriano Lameira, of the University of Warwick in England, and his colleagues. Lameira’s group recorded predator-warning calls known as “kiss-squeaks” — which typically involve drawing in breath through pursed lips — of 76 orangutans from six populations living on the islands of Borneo and Sumatra, where they face survival threats (SN: 2/15/18). The team tracked the animals and estimated their population densities from 2005 through 2010, with at least five consecutive months of observations and recordings in each population. Analyses of recordings then revealed how much individuals’ kiss-squeaks changed or remained the same over time. Orangutans in high-density populations, which up the odds of frequent social encounters, concoct many variations of kiss-squeaks, the researchers report. Novel reworkings of kiss-squeaks usually get modified further by other orangutans or drop out of use in crowded settings, they say. © Society for Science & the Public 2000–2022.

Keyword: Language; Evolution
Link ID: 28258 - Posted: 03.30.2022

Dave Davies Did Stone Age people conduct brain surgery? Medical historian Ira Rutkow points to evidence that suggests they did. "There have been many instances of skulls that have been found dating back to Neolithic times that have grooves in them where portions of the skull have been removed. And it's evident if you look at these skulls, that this was all done by hand," Rutkow says. There's no written record of Stone Age neurosurgery, but Rutkow theorizes it may have been conducted by a shaman on patients who were comatose or who had been otherwise injured. What's more, he says, physical evidence indicates that some patients likely survived: "With many of these older skulls, new bone growth had already formed, and bone in the skull can only form if the patient is alive," he says. Rutkow is a surgeon himself. His new book, Empire of the Scalpel, traces the history of surgery, from the days when barbers did most operations and patients died in great numbers, to today's high tech operations that use robots with artificial intelligence. He says that when looking back, it's important to keep in mind the body of knowledge that existed at a particular point in history — and to not judge surgeons of yore too harshly. "People write about medical history and they say, 'Oh, it was barbaric,' or 'The doctors were maltreating,'" he says. "We have to remember at all times that whatever I write about in the past was considered state of the art at the time. ... I would hate to think that 200 years from now, somebody is looking at what we are doing today and saying, 'Boy, that treatment that they were doing was just barbaric. How do they do that to people?'" © 2022 npr

Keyword: Brain Injury/Concussion; Evolution
Link ID: 28257 - Posted: 03.30.2022

By Veronique Greenwood Sharks are celebrated for their apparently ceaseless motion — a small handful of species such as great white sharks must even swim to breathe, keeping water washing over their gills. Still, all that moving doesn’t preclude sharks from having a rest. Sleep across the animal kingdom manifests itself in many peculiar ways, like the birds whose brains sleep one half at a time or the bats that spend almost every hour of their day snoozing. And in a paper published in Current Biology on Wednesday, researchers confirmed that the draughtsboard shark, a small nocturnal shark native to New Zealand, appears to be sleeping during periods of calm, reporting that their metabolism and posture change significantly during these bouts of repose. They do, however, in a creepy touch, keep their eyes open for a lot of it. Further research will be required to demonstrate that other kinds of sharks catch underwater z’s like the draughtsboard shark. But the new study supports the hypothesis that one reason organisms might have evolved sleep is as a tool for conserving energy. Draughtsboard sharks were identified last year as sleepers by this same group of researchers based in New Zealand and Australia. They watched captured sharks carefully in tanks and tested their responses to disturbances during their restful periods. (These sharks are not among those that swim to breathe; they hang out on the ocean floor and pump water over their gills.) The team found that it was more difficult to prompt the sharks into movement if they had been still for a long time, suggesting they were in fact sleeping. This time, said Craig Radford, a professor of marine science at the University of Auckland and an author of the new paper, the researchers were looking to compare the sharks’ metabolisms during these periods of calm, defined as being still for longer than five minutes, with when they were resting for shorter periods and when they were actively swimming. They used a specially built tank with instruments that let them monitor how much oxygen the sharks were using, a way to indirectly measure metabolism. Seven sharks each spent 24 hours in the tank, and the researchers found that these states were indeed quite different. © 2022 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28234 - Posted: 03.11.2022

Dominique Potvin When we attached tiny, backpack-like tracking devices to five Australian magpies for a pilot study, we didn’t expect to discover an entirely new social behaviour rarely seen in birds. Our goal was to learn more about the movement and social dynamics of these highly intelligent birds, and to test these new, durable and reusable devices. Instead, the birds outsmarted us. As our new research paper explains, the magpies began showing evidence of cooperative “rescue” behaviour to help each other remove the tracker. While we’re familiar with magpies being intelligent and social creatures, this was the first instance we knew of that showed this type of seemingly altruistic behaviour: helping another member of the group without getting an immediate, tangible reward. As academic scientists, we’re accustomed to experiments going awry in one way or another. Expired substances, failing equipment, contaminated samples, an unplanned power outage—these can all set back months (or even years) of carefully planned research. For those of us who study animals, and especially behaviour, unpredictability is part of the job description. This is the reason we often require pilot studies. Our pilot study was one of the first of its kind—most trackers are too big to fit on medium to small birds, and those that do tend to have very limited capacity for data storage or battery life. They also tend to be single-use only. A novel aspect of our research was the design of the harness that held the tracker. We devised a method that didn’t require birds to be caught again to download precious data or reuse the small devices. © 1986–2022 The Scientist.

Keyword: Evolution; Learning & Memory
Link ID: 28218 - Posted: 02.26.2022

ByTess Joosse Bite into a lemon and you’ll likely experience a clashing rush of sensations: crushing sharpness, mouth-watering tanginess, and pleasant brightness. But despite its assertiveness—and its role as one of the five main taste profiles (along with sweet, salty, savory, and bitter)—scientists don’t know much about how our acidic taste evolved. Enter Rob Dunn. The North Carolina State University ecologist and his collaborators have spent years scanning the scientific literature in search of an answer. In a paper published this week in the Proceedings of the Royal Society B, the team reports some clues. Science chatted with Dunn about how, and why, humans like to pucker up. This interview has been edited for clarity and length. Rob Dunn Ecologist Rob DunnAmanda Ward Q: Do other animals like sour foods? A: With almost all the other tastes, species have lost them through evolution. Dolphins appear to have no taste receptors other than salty, and cats don’t have sweet taste receptors. That’s what we expected to see with sour. What we see instead is all the species that have been tested [about 60 so far] are able to detect acidity in their food. Of those animals, pigs and primates seem to really like acidic foods. For example, wild pigs (Sus scrofa) are really attracted to fermented corn, and gorillas (Gorilla gorilla) have shown a preference for acidic fruits in the ginger family. Q: Sweet taste gives us a reward for energy, and bitter alerts us to potential poisons. Why might we have evolved a taste for sour? A: Sour taste was likely present in ancient fish—they’re the earliest vertebrate animals that we know can sense sour. The origin in fish was likely not to taste food with their mouths, but to sense acidity in the ocean—basically fish “tasting” with the outside of their body. Variations in dissolved carbon dioxide can create acidity gradients in the water, which can be dangerous for fish. Being able to sense acidity would have been important. © 2022 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28198 - Posted: 02.12.2022

ByMichael Price When it comes to killing and eating other creatures, chimpanzees—our closest relatives—have nothing on us. Animal flesh makes up much more of the average human’s diet than a chimp’s. Many scientists have long suggested our blood lust ramped up about 2 million years ago, based on the number of butchery marks found at ancient archaeological sites. The spike in calories from meat, the story goes, allowed one of our early ancestors, Homo erectus, to grow bigger bodies and brains. But a new study argues the evidence behind this hypothesis is statistically flawed because it fails to account for the fact that researchers have focused most of their time and attention on later sites. As a result of this unequal “sampling effort” over time at different sites, the authors say, it’s impossible to know how big a role meat eating played in human evolution. Even before the study, many experts suspected the link between carnivory and bigger brains and bodies in early humans might be complex, says Rachel Carmody, an evolutionary biologist at Harvard University who wasn’t involved in the work. The new results, though, “take the important step of demonstrating empirically that controlling for sampling effort actually changes the interpretation.” To conduct the study, W. Andrew Barr, a paleoanthropologist at George Washington University, and colleagues reviewed previously reported data on the appearance of butchery marks at nine archaeological hotbeds of early human activity across eastern Africa spanning 2.6 million to 1.2 million years ago. As expected, the scientist found an increase in the number of cutmarks on animal bones beginning about 2 million years ago. However, the researchers noticed that archaeologists tended to find more cutmarks at the sites that have received the most research attention. In other words, the more time and effort researchers poured into a site, the more likely they were to discover evidence of meat eating. © 2022 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28169 - Posted: 01.26.2022

By Christina Caron For the entirety of my adult life I have tried to avoid driving. I could claim all sorts of noble reasons for this: concern about the environment, a desire to save money, the health benefits gained from walking or biking. But the main reason is that I’m anxious. What if I did something stupid and accidentally pressed the gas pedal instead of the brake? What if a small child suddenly darted into the middle of the road? What if another driver was distracted or full of rage? By 2020 I had managed to avoid driving for eight years, even though I’d gotten my license in high school. Then came the pandemic. After more than a year of hunkering down in our Manhattan neighborhood, my little family of three was yearning for new surroundings. So, I booked lodging in the Adirondacks, about a three-hour drive from New York City, and — for the first time in my life — signed up for formal driving lessons. On that first day, I arrived queasy and full of impending doom, muscles tensed and brain on high alert. But my instructor assured me that we would not meet our demise — we wouldn’t be driving fast enough for that, he explained — and then he told me something that nobody ever had: “The fear never leaves you.” You have to learn to harness it, he said. Have just enough fear to stay alert and be aware of your surroundings, but not so much that it is making you overly hesitant. The idea that I didn’t need to completely erase my anxiety was freeing. Having some anxiety — especially when faced with a stressful situation — isn’t necessarily bad and can actually be helpful, experts say. Anxiety is an uncomfortable emotion, often fueled by uncertainty. It can create intense, excessive and persistent worry and fear, not just about stressful events but also about everyday situations. There are usually physical symptoms too, like fast heart rate, muscle tension, rapid breathing, sweating and fatigue. Too much anxiety can be debilitating. But a normal amount is meant to help keep us safe, experts say. © 2022 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 28168 - Posted: 01.22.2022