By Hannah Thomasy Ned and Sunny stretch out together on the warm sand. He rests his head on her back, and every so often he might give her an affectionate nudge with his nose. The pair is quiet and, like many long-term couples, they seem perfectly content just to be in each other’s presence. The couple are monogamous, which is quite rare in the animal kingdom. But Sunny and Ned are a bit scalier that your typical lifelong mates — they are shingleback lizards that live at Melbourne Museum in Australia. In the wild, shinglebacks regularly form long-term bonds, returning to the same partner during mating season year after year. One lizard couple in a long-term study had been pairing up for 27 years and were still going strong when the study ended. In this way, the reptiles are more like some of the animal kingdom’s most famous long-term couplers, such as albatrosses, prairie voles and owl monkeys, and they confound expectations many people have about the personalities of lizards. “There’s more socially going on with reptiles than we give them credit for,” said Sean Doody, a conservation biologist at the University of South Florida. Social behavior in reptiles has been largely overlooked for decades, but a handful of dedicated scientists have begun unraveling reptiles’ cryptic social structures. With the help of camera traps and genetic testing, scientists have discovered reptiles living in family groups, caring for their young and communicating with each other in covert ways. And they aren’t only doing this because they love lizards. Currently, one in five reptile species are threatened with extinction; researchers say learning more about reptile sociality could be crucial for conservation. Humans have a long history of animosity toward reptiles, and influential twentieth century scientists added to the idea of reptiles as cold, unintelligent beasts. In the mid-1900s, Paul MacLean, a neuroscientist at Yale and then the National Institute of Mental Health, began developing the triune brain hypothesis. He theorized that the human brain contained three parts: the reptilian R-complex, which governed survival and basic instinctual behaviors; the paleomammalian complex, which controlled emotional behavior; and the neomammalian cortex, which was responsible for higher functions like problem-solving and language. © 2022 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28528 - Posted: 10.26.2022

By David Grimm “Whooo’s a good boy?” “Whooo’s a pretty kitty?” When it comes to communicating with our pets, most of us can’t help but talk to them like babies. We pitch our voices high, extend our vowels, and ask short, repetitive questions. Dogs seem to like this. They’re far more likely to pay attention to us when we use this “caregiver speech,” research has shown. Now, scientists have found the same is true for cats, though only when their owner is talking. The work adds evidence that cats—like dogs—may bond with us in some of the same ways infants do. “It’s a fascinating study,” says Kristyn Vitale, an animal behaviorist and expert on cat cognition at Unity College, who was not involved with the work. “It further supports the idea that our cats are always listening to us.” Charlotte de Mouzon had a practical reason for getting into this line of research. An ethologist at Paris Nanterre University, she had previously been a cat behaviorist, consulting with owners on how to solve everything from litter box problems to aggressive behavior. “Sometimes people would ask me, ‘What’s the scientific evidence behind your approaches?’” she says. “I was frustrated that there were no studies being done on cat behavior in France.” So, she began a Ph.D. and was soon studying cat-human communication. As a first step, de Mouzon confirmed what most cat owners already know: We dip into “baby talk” when we address our feline friends–a habit de Mouzon is guilty of herself. “What’s up, my little ones?” she finds herself asking in a high-pitched voice when greeting her two kitties, Mila and Shere Khan. But do cats, like dogs, actually respond more to this “cat-directed speech”? To find out, de Mouzon recruited 16 cats and their owners—students at the Alfort National Veterinary School just outside of Paris. Because cats can be challenging to work with, de Mouzon studied them on feline-friendly turf, converting a common room in the students’ dormitory into a makeshift animal behavior lab filled with toys, a litter box, and places to hide.

Keyword: Animal Communication; Language
Link ID: 28525 - Posted: 10.26.2022

Ewen Callaway Set on a rocky outcrop in southern Siberia, Chagyrskaya Cave might not look like much. But for one family of Neanderthals, it was home. For the first time, researchers have identified a set of closely related Neanderthals: a father and his teenage daughter and two other, more-distant relatives. The discovery of the family — reported on 19 October in Nature1 — and seven other individuals (including a pair of possible cousins from another clan) in the same cave, along with two more from a nearby site, represents the largest ever cache of Neanderthal genomes. The findings also suggest that Neanderthal communities were small, and that females routinely left their families to join new groups. Gleaning insights into kinship and social structure is new territory for ancient-genome studies, which have typically focused on broader population history, says Krishna Veeramah, a population geneticist at Stonybrook University in New York. “The fact that we can do this with Neanderthals is incredible.” Buried treasure Set on the banks of the Charysh River in the foothills of the Altai mountains, Chagyrskaya is 100 kilometres west of Denisova Cave, an archaeological treasure trove in which humans, Neanderthals, Denisovans (and at least one Neanderthal–Denisovan hybrid) all lived intermittently over some 300,000 years2,3. Excavations of Chagyrskaya, however, have so far revealed only Neanderthal remains, dated to between 50,000 to 60,000 years ago, and characteristic stone tools. In 2020, a genome sequence from a female Neanderthal from Chagyrskaya suggested she belonged to population distinct from those that occupied Denisova Cave much earlier4. To study the cave’s inhabitants in greater depth, a team of researchers led by palaeogeneticist Laurits Skov and population geneticist Benjamin Peter at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, extracted DNA from 17 other ancient-human remains from Chagyrskaya, as well as several from a nearby cave, called Okladnikov. © 2022 Springer Nature Limited

Keyword: Evolution
Link ID: 28521 - Posted: 10.22.2022

By Benjamin Mueller Svante Pääbo, a Swedish scientist who peered back into human history by retrieving genetic material from 40,000-year-old bones, producing a complete Neanderthal genome and launching the field of ancient DNA studies, was awarded the Nobel Prize in Physiology or Medicine on Monday. The prize recognized an improbable scientific career. Having once dreamed of becoming an Egyptologist, Dr. Pääbo devoted his early years of research to extracting genetic material from mummies, only for that research to run aground because the samples might have become contaminated by his and his colleagues’ own DNA. Within about two decades, in 2006, he had launched an unlikely effort to decipher a Neanderthal genome. He designed so-called clean rooms dedicated to handling ancient DNA, which protected his fossils from the genetic material of living humans. And dramatic advances in sequencing technology allowed him to decode the sort of badly damaged DNA found in ancient bones. “It was certainly considered to be impossible to recover DNA from 40,000-year-old bones,” said Dr. Nils-Göran Larsson, the chairman of the Nobel Committee for Physiology or Medicine and a professor of medical biochemistry at the Karolinska Institute in Stockholm. In 2010, Dr. Pääbo unveiled the Neanderthal genome. The publication opened a window into questions about what made early humans different from modern ones. It also helped scientists track genetic differences in modern humans and understand what role those differences play in disease, including Covid-19. In 2020, Dr. Pääbo and a colleague found that the coronavirus caused more severe symptoms in people who had inherited a stretch of Neanderthal DNA. Even some of Dr. Pääbo’s biggest admirers described the prize as unexpected. Analysts have long speculated that the scientists who sequenced the modern human genome were strong contenders for a Nobel Prize, not thinking that the scientist who sequenced Neanderthal DNA would get there first. But geneticists said that the two projects were interwoven: Rapid advances in sequencing technology that followed the beginning of the Human Genome Project in 1990, they said, helped Dr. Pääbo to interpret tiny quantities of Neanderthal DNA, damaged as they were from tens of thousands of years underground. © 2022 The New York Times Company

Keyword: Evolution; Genes & Behavior
Link ID: 28500 - Posted: 10.05.2022

By Tess Joosse “Bird brain” insults be damned. The noggins of our flying friends are packed with neurons, and recent studies have shown birds can develop complex tools and even discriminate between paintings by Claude Monet and Pablo Picasso. But is this avian acumen a recent development, evolutionarily speaking, or does it trace back tens of millions of years? A remarkably preserved fossil unearthed in Brazil may hold some answers. The 80-million-year-old bird skull contains impressions of advanced brain structures, suggesting early birds were bright like modern ones. The preserved braincase, from a now-extinct bird lineage, is “exceptional … a big step forward,” says Matteo Fabbri, an evolutionary biologist at the Field Museum of Natural History who was not involved with the work. “This is the first time we have really good information regarding the brain of [this] group.” Birds began to evolve about 165 million to 150 million years ago from dinosaurs. Some of the earliest—whose ancestors were carnivorous icons such as Velociraptor—were the famous feathered Archaeopteryx. Over time, avians branched into a group called the enantiornithines and close cousins who became modern birds. Ranging from the size of hummingbirds to turkeys, enantiornithines took to the skies in the Mesozoic era beginning 130 million years ago. The creatures eventually spanned the globe before going extinct 66 million years ago from the same asteroid impact that killed off the dinosaurs. Their position between Archaeopteryx and living birds gives them a “magical place on the dino-bird family tree,” says Daniel Field, a paleontologist at the University of Cambridge and co-author of the new study. To reconstruct the brains of ancient birds, researchers need fossils that preserve the hollow space where a brain would sit: the braincase. But no enantiornithine skeletons have preserved that space—until the new find. © 2022 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28492 - Posted: 09.28.2022

By Darren Incorvaia Songbirds get a lot of love for their dulcet tones, but drummers may start to steal some of that spotlight. Woodpeckers, which don’t sing but do drum on trees, have brain regions that are similar to those of songbirds, researchers report September 20 in PLOS Biology. The finding is surprising because songbirds use these regions to learn their songs at an early age, yet it’s not clear if woodpeckers learn their drum beats (SN: 9/16/21). Whether woodpeckers do or not, the result suggests a shared evolutionary origin for both singing and drumming. The ability to learn vocalizations by listening to them, just like humans do when learning to speak, is a rare trait in the animal kingdom. Vocal learners, such as songbirds, hummingbirds and parrots, have independently evolved certain clusters of nerve cells called nuclei in their forebrains that control the ability. Animals that don’t learn vocally are thought to lack these brain features. While it’s commonly assumed that other birds don’t have these nuclei, “there’s thousands of birds in the world,” says Matthew Fuxjager, a biologist at Brown University in Providence, R.I. “While we say these brain regions only exist in these small groups of species, nobody’s really looked in a lot of these other taxa.” Fuxjager and his colleagues examined the noggins of several birds that don’t learn vocally to check if they really did lack these brain nuclei. Using molecular probes, the team checked the bird brains for activity of a gene called parvalbumin, a known marker of the vocal learning nuclei. Many of the birds, including penguins and flamingos, came up short, but there was one exception — male and female woodpeckers, which had three spots in their brains with high parvalbumin activity. © Society for Science & the Public 2000–2022.

Keyword: Animal Communication; Language
Link ID: 28486 - Posted: 09.21.2022

Michael Nolan Jellyfish, anemones and coral polyps, known collectively as cnidarians, have captured the imaginations of scientists across biological disciplines for centuries. Their radial symmetries and graceful, fluid movements lend them an undeniable appeal, but it’s their peculiar nervous systems that have drawn recent attention from neuroscientists. Unlike in most animals, whose neurons are gathered into bundles of nerves and larger structures like brains and ganglia, cnidarian neurons are distributed through their tissues in structures called nerve nets. This diffuse organization makes it possible to observe neural activity from many neurons simultaneously: Because neurons are spread in a thin layer, no neuron blocks an observer’s view of another. That means researchers can use techniques like calcium imaging to potentially capture the activity of a cnidarian’s entire nervous system, rather than a subset of neurons in the dense tangle of a mouse brain, for example. Neuroscientists are leveraging the accessibility of nerve nets to more deeply explore the properties of neural ensembles, groups of neurons that fire in a correlated fashion. Ensembles are a fundamental feature of the brain; they offer a simple example of functional structure in an animal’s nervous system and have become a popular target for systems neuroscientists because they combine population coding (how neural activity encodes information in populations of cells) and connectivity (how connections among neurons relate to population activity). Understanding how these groups form, how they coordinate patterns of neural activity, and how they drive behavior may reveal organizational principles also present in larger and more complicated nervous systems. © Simons Foundation Terms and Conditions Privacy Policy Image Credits

Keyword: Evolution
Link ID: 28485 - Posted: 09.21.2022

Sara Reardon More than 500,000 years ago, the ancestors of Neanderthals and modern humans were migrating around the world when a pivotal genetic mutation caused some of their brains to improve suddenly. This mutation, researchers report in Science1, drastically increased the number of brain cells in the hominins that preceded modern humans, probably giving them a cognitive advantage over their Neanderthal cousins. “This is a surprisingly important gene,” says Arnold Kriegstein, a neurologist at the University of California, San Francisco. However, he expects that it will turn out to be one of many genetic tweaks that gave humans an evolutionary advantage over other hominins. “I think it sheds a whole new light on human evolution.” When researchers first reported the sequence of a complete Neanderthal genome in 20142, they identified 96 amino acids — the building blocks that make up proteins — that differ between Neanderthals and modern humans, as well as some other genetic tweaks. Scientists have been studying this list to learn which of these changes helped modern humans to outcompete Neanderthals and other hominins. Cognitive advantage To neuroscientists Anneline Pinson and Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, one gene stood out. TKTL1 encodes a protein that is made when a fetus’s brain is first developing. A mutation in the human version changed one amino acid, resulting in a protein that is different from those found in hominin ancestors, Neanderthals and non-human primates. The researchers suspected that this protein could increase the proliferation of neural progenitor cells, which become neurons, as the brain develops, specifically in an area called the neocortex — a region involved in cognitive function. This, they reasoned, could contribute to modern humans’ cognitive advantage. © 2022 Springer Nature Limited

Keyword: Evolution; Genes & Behavior
Link ID: 28477 - Posted: 09.14.2022

By Erin Garcia de Jesús Human trash can be a cockatoo’s treasure. In Sydney, the birds have learned how to open garbage bins and toss trash around in the streets as they hunt for food scraps. People are now fighting back. Bricks, pool noodles, spikes, shoes and sticks are just some of the tools Sydney residents use to keep sulphur-crested cockatoos (Cacatua galerita) from opening trash bins, researchers report September 12 in Current Biology. The goal is to stop the birds from lifting the lid while the container is upright but still allowing the lid to flop open when a trash bin is tilted to empty its contents. This interspecies battle could be a case of what’s called an innovation arms race, says Barbara Klump, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Radolfzell, Germany. When cockatoos learn how to flip trash can lids, people change their behavior, using things like bricks to weigh down lids, to protect their trash from being flung about (SN Explores: 10/26/21). “That’s usually a low-level protection and then the cockatoos figure out how to defeat that,” Klump says. That’s when people beef up their efforts, and the cycle continues. Researchers are closely watching this escalation to see what the birds — and humans — do next. With the right method, the cockatoos might fly by and keep hunting for a different target. Or they might learn how to get around it. In the study, Klump and colleagues inspected more than 3,000 bins across four Sydney suburbs where cockatoos invade trash to note whether and how people were protecting their garbage. Observations coupled with an online survey showed that people living on the same street are more likely to use similar deterrents, and those efforts escalate over time. © Society for Science & the Public 2000–2022.

Keyword: Learning & Memory; Evolution
Link ID: 28476 - Posted: 09.14.2022

ByRodrigo Pérez Ortega We humans are proud of our big brains, which are responsible for our ability to plan ahead, communicate, and create. Inside our skulls, we pack, on average, 86 billion neurons—up to three times more than those of our primate cousins. For years, researchers have tried to figure out how we manage to develop so many brain cells. Now, they’ve come a step closer: A new study shows a single amino acid change in a metabolic gene helps our brains develop more neurons than other mammals—and more than our extinct cousins, the Neanderthals. The finding “is really a breakthrough,” says Brigitte Malgrange, a developmental neurobiologist at the University of Liège who was not involved in the study. “A single amino acid change is really, really important and gives rise to incredible consequences regarding the brain.” What makes our brain human has been the interest of neurobiologist Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics for years. In 2016, his team found that a mutation in the ARHGAP11B gene, found in humans, Neanderthals, and Denisovans but not other primates, caused more production of cells that develop into neurons. Although our brains are roughly the same size as those of Neanderthals, our brain shapes differ and we created complex technologies they never developed. So, Huttner and his team set out to find genetic differences between Neanderthals and modern humans, especially in cells that give rise to neurons of the neocortex. This region behind the forehead is the largest and most recently evolved part of our brain, where major cognitive processes happen. The team focused on TKTL1, a gene that in modern humans has a single amino acid change—from lysine to arginine—from the version in Neanderthals and other mammals. By analyzing previously published data, researchers found that TKTL1 was mainly expressed in progenitor cells called basal radial glia, which give rise to most of the cortical neurons during development. © 2022 American Association for the Advancement of Science.

Keyword: Development of the Brain; Evolution
Link ID: 28472 - Posted: 09.10.2022

Michael Heithaus Could you explain how fish sleep? Do they drift away on currents, or do they anchor themselves to a particular location when they sleep? – Laure and Neeraj, New York From the goldfish in your aquarium to a bass in a lake to the sharks in the sea – 35,000 species of fish are alive today, more than 3 trillion of them. All over the world, they swim in hot springs, rivers, ponds and puddles. They glide through freshwater and saltwater. They survive in the shallows and in the darkest depths of the ocean, more than five miles down. If those trillions of fish, three major types exist: bony fish, like trout and sardines; jawless fish, like the slimy hagfish; and sharks and rays, which are boneless – instead, they have skeletons made of firm yet flexible tissue called cartilage. And all of them, every last one, needs to rest. Whether you’re a human or a haddock, sleep is essential. It gives a body time to repair itself, and a brain a chance to reset and declutter. As a marine biologist, I’ve always wondered how fish can rest. After all, in any body of water, predators are all over the place, lurking around, ready to eat them. But somehow they manage, like virtually all creatures on Earth. See the mysterious spot off the coast of Mexico where sharks take a nap. How they do it Scientists are still learning about how fish sleep. What we do know: Their sleep is not like ours. © 2010–2022, The Conversation US, Inc.

Keyword: Sleep; Evolution
Link ID: 28465 - Posted: 09.07.2022

By Emily Anthes My cat is a bona fide chatterbox. Momo will meow when she is hungry and when she is full, when she wants to be picked up and when she wants to be put down, when I leave the room or when I enter it, or sometimes for what appears to be no real reason at all. But because she is a cat, she is also uncooperative. So the moment I downloaded MeowTalk Cat Translator, a mobile app that promised to convert Momo’s meows into plain English, she clammed right up. For two days I tried, and failed, to solicit a sound. On Day 3, out of desperation, I decided to pick her up while she was wolfing down her dinner, an interruption guaranteed to elicit a howl of protest. Right on cue, Momo wailed. The app processed the sound, then played an advertisement for Sara Lee, then rendered a translation: “I’m happy!” I was dubious. But MeowTalk provided a more plausible translation about a week later, when I returned from a four-day trip. Upon seeing me, Momo meowed and then purred. “Nice to see you,” the app translated. Then: “Let me rest.” (The ads disappeared after I upgraded to a premium account.) The urge to converse with animals is age-old, long predating the time when smartphones became our best friends. Scientists have taught sign language to great apes, chatted with grey parrots and even tried to teach English to bottlenose dolphins. Pets — with which we share our homes but not a common language — are particularly tempting targets. My TikTok feed brims with videos of Bunny, a sheepadoodle who has learned to press sound buttons that play prerecorded phrases like “outside,” “scritches” and “love you.” MeowTalk is the product of a growing interest in enlisting additional intelligences — machine-learning algorithms — to decode animal communication. The idea is not as far-fetched as it may seem. For example, machine-learning systems, which are able to extract patterns from large data sets, can distinguish between the squeaks that rodents make when they are happy and those that they emit when they are in distress. Applying the same advances to our creature companions has obvious appeal. “We’re trying to understand what cats are saying and give them a voice” Javier Sanchez, a founder of MeowTalk, said. “We want to use this to help people build better and stronger relationships with their cats,” he added. © 2022 The New York Times Company

Keyword: Animal Communication; Learning & Memory
Link ID: 28458 - Posted: 08.31.2022

Sofia Quaglia Dolphins form decade-long social bonds, and cooperate among and between cliques, to help one another find mates and fight off competitors, new research has found – behaviour not previously confirmed among animals. “These dolphins have long-term stable alliances, and they have intergroup alliances. Alliances of alliances of alliances, really,” said Dr Richard Connor, a behavioural ecologist at the University of Massachusetts Dartmouth and one of the lead authors of the paper. “But before our study, it had been thought that cooperative alliances between groups were unique to humans.” The findings, published on Monday in the journal Proceedings of the National Academy of Sciences, appear to support the “social brain” hypothesis: that mammals’ brains evolved to be larger in size for animals that keep track of their social interactions and networks. Humans and dolphins are the two animals with the largest brains relative to body size. “It’s not a coincidence,” Connor said. Connor’s team of researchers collected data between 2001 and 2006 by conducting intensive boat-based surveys in Shark Bay, Western Australia. The researchers tracked the dolphins by watching and listening to them, using their unique identifying whistles to tell them apart. They observed 202 Indo-Pacific bottlenose dolphins (Tursiops aduncus), including during the peak mating season between September and November. Back in the lab, they pored over data focusing on 121 of these adult male dolphins to observe patterns in their social networks. And for the next decade they continued to analyse the animals’ alliances. Dolphins’ social structures are fluid and complex. The researchers found alliances among two or three male dolphins – like best friends. Then the groups expanded to up to 14 members. Together, they helped each other find females to herd and mate with, and they help steal females from other dolphins as well as defend against any “theft” attempts from rivals. © 2022 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 28457 - Posted: 08.31.2022

By Carl Zimmer One of the most remarkable things about our species is how fast human culture can change. New words can spread from continent to continent, while technologies such as cellphones and drones change the way people live around the world. It turns out that humpback whales have their own long-range, high-speed cultural evolution, and they don’t need the internet or satellites to keep it running. In a study published on Tuesday, scientists found that humpback songs easily spread from one population to another across the Pacific Ocean. It can take just a couple of years for a song to move several thousand miles. Ellen Garland, a marine biologist at the University of St. Andrews in Scotland and an author of the study, said she was shocked to find whales in Australia passing their songs to others in French Polynesia, which in turn gave songs to whales in Ecuador. “Half the globe is now vocally connected for whales,” she said. “And that’s insane.” It’s even possible that the songs travel around the entire Southern Hemisphere. Preliminary studies by other scientists are revealing whales in the Atlantic Ocean picking up songs from whales the eastern Pacific. Each population of humpback whales spends the winter in the same breeding grounds. The males there sing loud underwater songs that can last up to half an hour. Males in the same breeding ground sing a nearly identical tune. And from one year to the next, the population’s song gradually evolves into a new melody. Dr. Garland and other researchers have uncovered a complex, language-like structure in these songs. The whales combine short sounds, which scientists call units, into phrases. They then combine the phrases into themes. And each song is made of several themes. © 2022 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 28456 - Posted: 08.31.2022

Steven Strogatz Dreams are so personal, subjective and fleeting, they might seem impossible to study directly and with scientific objectivity. But in recent decades, laboratories around the world have developed sophisticated techniques for getting into the minds of people while they are dreaming. In the process, they are learning more about why we need these strange nightly experiences and how our brains generate them. In this episode, Steven Strogatz speaks with sleep researcher Antonio Zadra of the University of Montreal about how new experimental methods have changed our understanding of dreams. Steven Strogatz (00:03): I’m Steve Strogatz, and this is The Joy of Why, a podcast from Quanta Magazine that takes you into some of the biggest unanswered questions in math and science today. (00:13) In this episode, we’re going to be talking about dreams. What are dreams exactly? What purpose do they serve? And why are they often so bizarre? We’ve all had this experience: You’re dreaming about something fantastical, some kind of crazy story with a narrative arc that didn’t actually happen, with people we don’t necessarily know, in places we may have never even been. Is this just the brain trying to make sense of random neural firing? Or is there some evolutionary reason for dreaming? Dreams are inherently hard to study. Even with all the advances in science and technology, we still haven’t really found a way to record what someone else is dreaming about. Plus, as we all know, it’s easy to forget our dreams as soon as we wake up, unless we’re really careful to write them down. But even with all these difficulties, little by little, dream researchers are making progress in figuring out how we dream and why we dream. (01:11) Joining me now to discuss all this is Dr. Antonio Zadra, a professor at the University of Montreal and a researcher at the Center for Advanced Research in Sleep Medicine. His specialties include the study of nightmares, recurrent dreams and lucid dreaming. He’s also the coauthor of the recent book When Brains Dream, exploring the science and mystery of sleep. Tony, thank you so much for joining us today. Strogatz (01:39): I’m very excited to talk to you about this. So let’s start with thinking about the science of dreams as you and your colleagues see it today. Why are dreams so hard to study? All Rights Reserved © 2022

Keyword: Sleep; Evolution
Link ID: 28454 - Posted: 08.27.2022

Jason Bruck Bottlenose dolphins’ signature whistles just passed an important test in animal psychology. A new study by my colleagues and me has shown that these animals may use their whistles as namelike concepts. By presenting urine and the sounds of signature whistles to dolphins, my colleagues Vincent Janik, Sam Walmsey and I recently showed that these whistles act as representations of the individuals who own them, similar to human names. For behavioral biologists like us, this is an incredibly exciting result. It is the first time this type of representational naming has been found in any other animal aside from humans. When you hear your friend’s name, you probably picture their face. Likewise, when you smell a friend’s perfume, that can also elicit an image of the friend. This is because humans build mental pictures of each other using more than just one sense. All of the different information from your senses that is associated with a person converges to form a mental representation of that individual - a name with a face, a smell and many other sensory characteristics. Within the first few months of life, dolphins invent their own specific identity calls – called signature whistles. Dolphins often announce their location to or greet other individuals in a pod by sending out their own signature whistles. But researchers have not known if, when a dolphin hears the signature whistle of a dolphin they are familiar with, they actively picture the calling individual. My colleagues and I were interested in determining if dolphin calls are representational in the same way human names invoke many thoughts of an individual. Because dolphins cannot smell, they rely principally on signature whistles to identify each other in the ocean. Dolphins can also copy another dolphin’s whistles as a way to address each other. My previous research showed that dolphins have great memory for each other’s whistles, but scientists argued that a dolphin might hear a whistle, know it sounds familiar, but not remember who the whistle belongs to. My colleagues and I wanted to determine if dolphins could associate signature whistles with the specific owner of that whistle. This would address whether or not dolphins remember and hold representations of other dolphins in their minds. © 2010–2022, The Conversation US, Inc.

Keyword: Language; Evolution
Link ID: 28441 - Posted: 08.24.2022

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