Chapter 6. Evolution of the Brain and Behavior

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By Calli McMurray, Angie Voyles Askham, Claudia López Lloreda, Shaena Montanari Neuroscience can sometimes feel like an old mouse club—but it wasn’t always that way. In the 1960s and ’70s, neuroscientists routinely put on their field boots to search for the “animal that was expert at doing the task that you were interested in studying,” says Eve Marder, university professor of biology at Brandeis University. “People studied insects and annelids and mollusks and every kind of animal imaginable. And if they could have studied elephants, they would have.” Many fundamental—and Nobel-prize-winning—discoveries emerged from this approach. Recording from the squid’s giant axon, for example, revealed how action potentials work; experiments in sea slugs illuminated the molecular changes that drive learning and memory; work in barn owls unraveled sound localization; and studies in horseshoe crabs first exposed lateral inhibition in photoreceptors. But by the end of the 20th century, model diversity had fallen out of vogue. A small band of neuroethologists continued to explore animals off the beaten path, but the majority of neuroscientists soon jumped over to standard animal models, Marder says. Many of today’s common model organisms—including the mouse, zebrafish, roundworm and fruit fly—soared in popularity because they are cheap, easy to work with and quick to raise in a lab. The invention of molecular and genetic tools tailored to these species only increased their appeal, as did attention from the U.S. federal government. In 1999, the National Institutes of Health (NIH) published a list of 13 canonical model organisms for biomedical research, and in 2004 the organization’s “road map” encouraged the use of research animals for which genetic tools were available. Now, two decades later, a non-model organism “renaissance” is underway, says Ishmail Abdus-Saboor, associate professor of biological sciences at Columbia University, as a growing number of neuroscientists step outside of the model organism box. This shift is largely due to cost reductions and technological advances in “species-neutral” techniques, says Sam Reiter, assistant professor of computational neuroethology at the Okinawa Institute of Science and Technology, such as high-throughput extracellular recordings, machine-learning-based behavioral tracking, genome and transcriptome sequencing, and gene-editing tools. “This lets researchers quickly reach close to the cutting edge, even if working on an animal where little is known.” © 2024 Simons Foundation

Keyword: Evolution
Link ID: 29605 - Posted: 12.21.2024

By Sofia Quaglia It’s amazing what chimpanzees will do for a snack. In Congolese rainforests, the apes have been known to poke a hole into the ground with a stout stick, then grab a long stem and strip it through their teeth, making a brush-like end. Into the hole that lure goes, helping the chimps fish out a meal of termites. How did the chimps figure out this sophisticated foraging technique and others? “It’s difficult to imagine that it can just have appeared out of the blue,” said Andrew Whiten, a cultural evolution expert from the University of St. Andrews in Scotland who has studied tool use and foraging in chimpanzees. Now Dr. Whiten’s team has set out to demonstrate that advanced uses of tools are an example of humanlike cultural transmission that has accumulated over time. Where bands of apes in Central and East Africa exhibit such complex behaviors, they say, there are also signs of genes flowing between groups. They describe this as evidence that such foraging techniques have been passed from generation to generation, and innovated over time across different interconnected communities. In a study published on Thursday in the journal Science, Dr. Whiten and colleagues go as far as arguing that chimpanzees have a “tiny degree of cumulative culture,” a capability long thought unique to humans. From mammals to birds to reptiles and even insects, many animals exhibit some evidence of culture, when individuals can socially learn something from a nearby individual and then start doing it. But culture becomes cumulative over time when individuals learn from others, each building on the technique so much that a single animal wouldn’t have been able to learn all of it on its own. For instance, some researchers interpret using rocks as a hammer and anvil to open a nut as something chimpanzees would not do spontaneously without learning it socially. Humans excel at this, with individual doctors practicing medicine each day, but medicine is no one single person’s endeavor. Instead, it is an accumulation of knowledge over time. Most chimpanzee populations do not use a complex set of tools, in a specific sequence, to extract food. © 2024 The New York Times Company

Keyword: Evolution; Learning & Memory
Link ID: 29573 - Posted: 11.23.2024

By Janna Levin It’s fair to say that enjoyment of a podcast would be severely limited without the human capacity to create and understand speech. That capacity has often been cited as a defining characteristic of our species, and one that sets us apart in the long history of life on Earth. Yet we know that other species communicate in complex ways. Studies of the neurological foundations of language suggest that birdsong, or communication among bats or elephants, originates with brain structures similar to our own. So why do some species vocalize while others don’t? In this episode, Erich Jarvis, who studies behavior and neurogenetics at the Rockefeller University, chats with Janna Levin about the surprising connections between human speech, birdsong and dance. JANNA LEVIN: All animals exhibit some form of communication, from the primitive hiss of a lizard to the complex gestures natural to chimps, or the songs shared by whales. But human language does seem exceptional, a vast and discrete cognitive leap. Yet recent research is finding surprising neurological connections between our expressive speech and the types of communication innate to other animals, giving us new ideas about the biological and developmental origins of language. Erich is a professor at the Rockefeller University and a Howard Hughes Medical Institute investigator. At Rockefeller, he directs the Field Research Center of Ethology and Ecology. He also directs the Neurogenetics Lab of Language and codirects the Vertebrate Genome Lab, where he studies song-learning birds and other species to gain insight into the mechanism’s underlying language and vocal learning. ERICH JARVIS: So, the first part: Language is built-in genetically in us humans. We’re born with the capacity to learn how to produce and how to understand language, and pass it on culturally from one generation to the next. The actual detail is learned, but the actual plan in the brain is there. Second part of your question: Is it, you know, special or unique to humans? It is specialized in humans, but certainly many components of what gives rise to language is not unique to humans. There’s a spectrum of abilities out there in other species that we share some aspects of with other species. © 2024 Simons Foundation

Keyword: Language; Evolution
Link ID: 29572 - Posted: 11.23.2024

By Ann Gibbons As the parent of any teenager knows, humans need a long time to grow up: We take about twice as long as chimpanzees to reach adulthood. Anthropologists theorize that our long childhood and adolescence allow us to build comparatively bigger brains or learn skills that help us survive and reproduce. Now, a study of an ancient youth’s teeth suggests a slow pattern of growth appeared at least 1.8 million years ago, half a million years earlier than any previous evidence for delayed dental development. Researchers used state-of-the art x-ray imaging methods to count growth lines in the molars of a member of our genus, Homo, who lived 1.77 million years ago in what today is Dmanisi, Georgia. Although the youth developed much faster than children today, its molars grew as slowly as a modern human’s during the first 5 years of life, the researchers report today in Nature. The finding, in a group whose brains are hardly larger than chimpanzees, could provide clues to why humans evolved such long childhoods. “One of the main questions in paleoanthropology is to understand when this pattern of slow development evolves in [our genus] Homo,” says Alessia Nava, a bioarchaeologist at the Sapienza University of Rome who is not part of the study. “Now, we have an important hint.” Others caution that although the teeth of this youngster grew slowly, other individuals, including our direct ancestors, might have developed faster. Researchers have known since the 1930s that humans stay immature longer than other apes. Some posit our ancestors evolved slow growth to allow more time and energy to build bigger brains, or to learn how to adapt to complex social interactions and environments before they had children. To pin down when this slow pattern of growth arose, researchers often turn to teeth, especially permanent molars, because they persist in the fossil record and contain growth lines like tree rings. What’s more, the dental growth rate in humans and other primates correlates with the development of the brain and body.

Keyword: Evolution; Sexual Behavior
Link ID: 29562 - Posted: 11.16.2024

Ari Daniel The birds of today descended from the dinosaurs of yore. Researchers have known relatively little, however, about how the bird's brain took shape over tens of millions of years. "Birds are one of the most intelligent groups of living vertebrate animals," says Daniel Field, a vertebrate biologist at the University of Cambridge. "They really rival mammals in terms of their relative brain size and the complexity of their behaviors, social interactions, breeding displays." Now, a newly discovered fossil provides the most complete glimpse to date of the brains of the ancestral birds that once flew above the dinosaurs. The species was named Navaornis hestiae, and it's described in the journal Nature. Piecing together how bird brains evolved has been a challenge. First, most of the fossil evidence dates back to tens of millions of years before the end of the Cretaceous period when dinosaurs went extinct and birds diversified. In addition, the fossils of feathered dinosaurs that have turned up often have a key problem. "They're beautiful, but they're all like roadkill," says Luis Chiappe, a paleontologist and curator at the Natural History Museum of Los Angeles County. "They're all flattened and there are aspects that you're never going to be able to recover from those fossils." The shape and three-dimensional structure of the brain are among those missing aspects. But in 2016, Brazilian paleontologist William Nava discovered a remarkably well-preserved fossil in São Paulo state. It came from a prehistoric bird that fills in a crucial gap in understanding of how modern bird brains evolved. © 2024 npr

Keyword: Evolution; Development of the Brain
Link ID: 29561 - Posted: 11.16.2024

By Miryam Naddaf When a dog shakes water off its fur, the action is not just a random flurry of movements — nor a deliberate effort to drench anyone standing nearby. This instinctive reflex is shared by many furry mammals including mice, cats, squirrels, lions, tigers and bears. The move helps animals to remove water, insects or other irritants from hard-to-reach places. But underlying the shakes is a complex — and previously mysterious — neurological mechanism. Now, researchers have identified the neural circuit that triggers characteristic ‘wet dog’ shaking behaviour in mice — which involves a specific class of touch receptors, and neurons that connect the spinal cord to the brain. Their findings were published in Science on 7 November1. “The touch system is so complex and rich that [it] can distinguish a water droplet from a crawling insect from the gentle touch of a loved one,” says Kara Marshall, a neuroscientist at Baylor College of Medicine in Houston, Texas. “It’s really remarkable to be able to link a very specific subset of touch receptors to this familiar and understandable behaviour.” The hairy skin of mammals is packed with more than 12 types of sensory neuron, each with a unique function to detect and interpret various sensations. Study co-author Dawei Zhang, a neuroscientist then at Harvard Medical School in Boston, Massachusetts, and his colleagues focused on a type of ultra-sensitive touch detecting receptors called C-fibre low-threshold mechanoreceptors (C-LTMRs), which wrap around hair follicles. In humans, these receptors are associated with pleasant touch sensations, such as a soft hug or a soothing stroke. But in mice and other animals, they serve a protective role: alerting them to the presence of something on their skin, whether it’s water, dirt or a parasite. When these stimuli cause hairs on the skin to bend it activates the C-LTMRs, says Marshall, “extending the sensibility of the skin beyond just the surface”. © 2024 Springer Nature Limited

Keyword: Pain & Touch; Evolution
Link ID: 29551 - Posted: 11.09.2024

By Sara Reardon Elephants love showering to cool off, and most do so by sucking water into their trunks and spitting it over their bodies. But an elderly pachyderm named Mary has perfected the technique by using a hose as a showerhead, much in the way humans do. The behavior is a remarkable example of sophisticated tool use in the animal kingdom. But the story doesn’t end there. Mary’s long, luxurious baths have drawn so much attention that an envious elephant at the Berlin Zoo has figured out how to shut the water off on her supersoaking rival—a type of sabotage rarely seen among animals. Both behaviors, reported today in Current Biology, further cement elephants as complex thinkers, says Lucy Bates, a behavioral ecologist at the University of Portsmouth not involved in the study. The work, she says, “suggests problem solving or even ‘insight.’” Many elephants enjoy playing with hoses, probably because they remind them of trunks, says Michael Brecht, a computational neuroscientist at Humboldt University of Berlin. But Mary takes the activity to another level. Using her trunk, the 54-year-old Asian elephant (Elephas maximus)—a senior citizen, given the average captive life span of her species of 48 years—holds a hose over her head and waves it back and forth. She also changes her grip on the hose to spray different parts of her body and swings it like a lasso to throw water over her back. Brecht’s graduate student, Lena Kaufmann, noticed Mary’s hose use while studying other types of behavior in the zoo’s elephants; the zookeepers told her Mary did this frequently. So Kaufman and her colleagues started to record the showering on video over the course of a year, testing how Mary reacted to changes in the setup.

Keyword: Learning & Memory; Evolution
Link ID: 29547 - Posted: 11.09.2024

By Kerri Smith Infographics by Nik Spencer There must be something about the human brain that’s different from the brains of other animals — something that enables humans to plan, imagine the future, solve crossword puzzles, tell sarcastic jokes and do the many other things that together make our species unique. And something that explains why humans get devastating conditions that other animals don’t — such as bipolar disorder and schizophrenia. Brain size is tightly correlated with body size in most animals. But humans break the mould. Our brains are much larger than expected given our body size. Here are some animals’ brains ranked according to size. Researchers often use a ratio called the encephalization quotient (EQ) to get an idea of how much larger or smaller an animal’s brain is compared with what would be expected given its body size. The EQ is 1.0 if the brain to body mass ratio meets expectations. Here are their brains scaled according to their EQ, with the actual brain sizes represented by dotted lines. The mouse brain is half as big as expected for its body size. The human brain is more than seven times the expected size. Although evolution has enlarged the human brain, it hasn’t done so uniformly: some brain areas have ballooned more than others. One particularly enlarged region is the cortex, an area that carries out planning, reasoning, language and many other behaviours that humans excel at. Other areas, such as the cerebellum — an area at the back of the brain that is densely populated with neurons, and which helps to conduct movement and planning — have expanded too. The prefrontal cortex has a similar structure in both chimps and humans, although it takes up much more real estate in the human brain than in the chimp brain.

Keyword: Evolution
Link ID: 29539 - Posted: 11.02.2024

Ian Sample Science editor Humans may have turned drinking into something of an art form but when it comes to animals putting alcohol away, Homo sapiens are not such an outlier, researchers say. A review of published evidence shows that alcohol occurs naturally in nearly every ecosystem on Earth, making it likely that most animals that feast on sugary fruits and nectar regularly imbibe the intoxicating substance. Although many creatures have evolved to tolerate a tipple and gain little more than calories from their consumption, some species have learned to protect themselves with alcohol. Others, however, seem less able to handle its effects. “We’re moving away from this anthropocentric view that alcohol is used by just humans and that actually ethanol is quite abundant in the natural world,” said Anna Bowland, a researcher in the team at the University of Exeter. After trawling research papers on animals and alcohol, the scientists arrived at a “diverse coterie” of species that have embraced and adapted to ethanol in their diets, normally arising through fermented fruits, sap and nectar. Ethanol became plentiful on Earth about 100m years ago when flowering plants began to produce sugary fruits and nectar that yeast could ferment. The alcohol content is typically low, at around 1% to 2% alcohol by volume (ABV), but in over-ripe palm fruit the concentration can reach 10% ABV. In one study, wild chimpanzees in south eastern Guinea were caught on camera bingeing on the alcoholic sap of raffia palms. Meanwhile, spider monkeys on Barro Colorado Island, Panama, are partial to ethanol-laden yellow mombin fruit, revealed to contain between 1% and 2.5% alcohol. “Evidence is growing that humans are not drinking alone,” the authors write in Trends in Ecology and Evolution. © 2024 Guardian News & Media Limited

Keyword: Drug Abuse; Evolution
Link ID: 29537 - Posted: 11.02.2024

By Thomas Fuller Over and over, the crows attacked Lisa Joyce as she ran screaming down a Vancouver street. They dive bombed, landing on her head and taking off again eight times by Ms. Joyce’s count. With hundreds of people gathered outdoors to watch fireworks that July evening, Ms. Joyce wondered why she had been singled out. “I’m not a fraidy-cat, I’m not generally nervous of wildlife,” said Ms. Joyce, whose crow encounters grew so frequent this past summer that she changed her commute to work to avoid the birds. “But it was so relentless,” she said, “and quite terrifying.” Ms. Joyce is far from alone in fearing the wrath of the crow. CrowTrax, a website started eight years ago by Jim O’Leary, a Vancouver resident, has since received more than 8,000 reports of crow attacks in the leafy city, where crows are relatively abundant. And such encounters stretch well beyond the Pacific Northwest. A Los Angeles resident, Neil Dave, described crows attacking his house, slamming their beaks against his glass door to the point where he was afraid it would shatter. Jim Ru, an artist in Brunswick, Maine, said crows destroyed the wiper blades of dozens of cars in the parking lot of his senior living apartment complex. Nothing seemed to dissuade them. Renowned for their intelligence, crows can mimic human speech, use tools and gather for what seem to be funeral rites when a member of their murder, as groups of crows are known, dies or is killed. They can identify and remember faces, even among large crowds. They also tenaciously hold grudges. When a murder of crows singles out a person as dangerous, its wrath can be alarming, and can be passed along beyond an individual crow’s life span of up to a dozen or so years, creating multigenerational grudges. © 2024 The New York Times Company

Keyword: Intelligence; Learning & Memory
Link ID: 29534 - Posted: 10.30.2024

By Phie Jacobs Whether it’s two newlyweds going in for a smooch after saying “I do” or a parent soothing their child’s scraped knee, kissing is one of humanity’s most recognizable symbols of affection. Clay tablets from ancient Mesopotamia dating to 2500 B.C.E. provide the earliest archaeological evidence of romantic kissing. But the behavior may be older than civilization itself, with some studies suggesting Neanderthals swapped spit with modern humans—and shared each other’s oral microbes—more than 100,000 years ago. Some researchers have suggested kissing evolved from behaviors such as sniffing, nursing babies, or even parents passing chewed-up food to their offspring. But in an article published this month in Evolutionary Anthropology, evolutionary psychologist Adriano Lameira of the University of Warwick offers another hypothesis. Drawing on his knowledge of great ape behavior, Lameira suggests kissing got its start as a fur grooming ritual still observed in modern-day chimpanzees and other great apes. Science sat down with Lameira to learn more about his work. This interview has been edited for length and clarity. Q: What made you want to study kissing? A: It’s a behavior that is charged with so much meaning and symbolism, perhaps the most iconic way of how we show affection on an individual and societal level. I was surprised to find that we know so little about its evolution and nature. In our lab, we’re mostly intrigued by the evolution of language, dance, and imagination. But in the largest sense we’re interested in behaviors and rituals that are evolutionary heirlooms from our apelike ancestors—things our ancestors did that set us on course towards who we are today. Q: Do other animals kiss, or is the behavior unique to humans? © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 29532 - Posted: 10.30.2024

Emily Anthes In the summer of 2018, off the coast of British Columbia, an orca named Tahlequah gave birth. When the calf died after just half an hour, Tahlequah refused to let go. For more than two weeks, she carried her calf’s body around, often balancing it on her nose as she swam. The story went viral, which came as no surprise to Susana Monsó, a philosopher of animal minds at the National Distance Education University in Madrid. Despite the vast chasm that seems to separate humans and killer whales, this orca mother was behaving in a way that was profoundly relatable. “This idea of a mother clinging on to the corpse of her baby for 17 days seems like something we can understand, something we can relate to, for those of us who have experienced loss,” Dr. Monsó said. Of course, projecting our own human experiences onto other species can be a tricky business, and scientists often warn about the mistakes we can make when we engage in this sort of anthropomorphism. But we can also be misled by our tendency to assume that many cognitive and emotional traits are unique to humans, Dr. Monsó said. And in her new book, “Playing Possum,” she argues that a variety of animal species have at least a rudimentary concept of death. Dr. Monsó spoke with The New York Times about her work. This conversation has been condensed and edited for clarity. How did you get interested in this aspect of animal minds? I’ve always been interested in those capacities that are understood to be uniquely human, such as morality or rationality. Death was a natural topic to pick up. There had been a growing number of reports of animals reacting in different ways to corpses. This seemed to be the birth of a new discipline, which is called comparative thanatology: the study of animals’ relationship with death. © 2024 The New York Times Company

Keyword: Intelligence; Animal Communication
Link ID: 29530 - Posted: 10.30.2024

By Christa Lesté-Lasserre Even if your cat hasn’t gotten your tongue, it’s most likely getting your words. Without any particular training, the animals—like human babies—appear to pick up basic human language skills just by listening to us talk. Indeed, cats learn to associate images with words even faster than babies do, according to a study published this month in Scientific Reports. That means that, despite all appearances to the contrary, our furtive feline friends may actually be listening to what we say. Cats have a long history with us—about 10,000 years at last count—notes Brittany Florkiewicz, an evolutionary psychologist at Lyon College who was not involved in the work. “So it makes sense that they can learn these types of associations.” Scientists have discovered a lot about how cats respond to human language in the past 5 years. In 2019, a team in Tokyo showed that cats “know” their names, responding to them by moving their heads and ears in a particular way. In 2022, some of the same researchers demonstrated that the animals can “match” photos of their human and feline family members to their respective names. “I was very surprised, because that meant cats were able to eavesdrop on human conversations and understand words without any special reward-based training,” says Saho Takagi, a comparative cognitive scientist at Azabu University and member of the 2022 study. She wondered: Are cats “hard-wired” to learn human language? To find out, Takagi and some of her former teammates gave 31 adult pet cats—including 23 that were up for adoption at cat cafés—a type of word test designed for human babies. The scientists propped each kitty in front of a laptop and showed the animals two 9-second animated cartoon images while broadcasting audio tracks of their caregivers saying a made-up word four times. The researchers played the nonsense word “keraru” while a growing and shrinking blue-and-white unicorn appeared on the screen, or “parumo” while a red-faced cartoon Sun grew and shrank. The cats watched and heard these sequences until they got bored—signaled by a 50% drop in eye contact with the screen.

Keyword: Language; Development of the Brain
Link ID: 29521 - Posted: 10.19.2024

By Erica Goode Over the last decades, researchers who study animal behavior have succeeded in largely blurring the line between Homo sapiens and other animals. Like their human counterparts, animals feel emotions, they solve problems, they communicate and form complicated relationships, investigators have found. Any number of books — think of Ed Yong’s “An Immense World” or Marc Bekoff’s “The Emotional Lives of Animals” — have been dedicated to exploring these relatively recently recognized abilities. Yet few books on the ways animals communicate have been written through the eyes of a scientist as cautious and as thoughtful as zoologist Arik Kershenbaum, the author of “Why Animals Talk: The New Science of Animal Communication.” Kershenbaum, a lecturer and fellow at the University of Cambridge, is distrustful of simplistic explanations, wary of assumptions, devoted to caveats — few statements come without qualification. In Socratic fashion, he asks a lot of questions, the answers to which, in many cases, neither he nor anyone else can yet provide. That did not deter him from writing the book and it should not deter other people from reading it. But those who pick up “Why Animals Talk” expecting to find proof of animal telepathy or hoping for a dictionary of elephant-speak or a word-for-word translation of humpback whale songs, will be disappointed. (On Amazon, one disgruntled reviewer summarized the book: “Animals don’t really talk – The End.”) If there is a message that Kershenbaum wants to get across, it’s that, as much as we’d like to be able to hold conversations with our pets or chat with chimpanzees at the zoo, it makes no sense to expect animals to communicate in the same way that humans do, “with the same equipment as we have, the same ears and eyes and brains.”

Keyword: Animal Communication; Language
Link ID: 29513 - Posted: 10.12.2024

By Sofia Quaglia Parenting can be lots of work for a bird: all that flying back and forth transporting grubs and insects to a nest of demanding young. But some birds manage to forgo caring for their chicks — while still ensuring they’re well looked after. These birds lay their eggs in the nests of other birds that unknowingly adopt the hatchlings, nourishing and protecting them as their own. Only about 1 percent of all bird species resort to this sneaky family planning method, called obligate brood parasitism, but it has evolved at least seven separate times in the history of birds and is a way of life for at least 100 species. Since some brood parasites rely on several different bird species as foster parents, more than a sixth of all species in the avian world care for chicks that aren’t their own at some point. Throughout the millennia, these trespassers have evolved ingenious ways to fool the hosts, and the hosts have developed equally clever ways to protect themselves and their own. At each stage of the nesting cycle, it’s a game of subterfuge that plays out in color, sound and behavior. “There’s always something new — it’s like, ‘Oh, man, this group of birds went down a slightly different pathway,’” says behavioral ecologist Bruce Lyon of the University of California, Santa Cruz, who studies the black-headed duck (Heteronetta atricapilla), the sole obligate parasitic duck species. While many mysteries remain, new research is constantly unearthing just how intense this evolutionary tug-of-war can get.

Keyword: Sexual Behavior; Evolution
Link ID: 29505 - Posted: 10.05.2024

By Joanna Thompson, Hakai Magazine From January to May each year, Qeqertarsuaq Tunua, a large bay on Greenland’s west coast, teems with plankton. Baleen whales come to feast on the bounty, and in 2010, two bowhead whales entered the bay to gorge. As the pair came within 100 kilometers (about 60 miles) of one another, they were visually out of range, but could likely still hear one another. That’s when something extraordinary happened: They began to synchronize their dives. Researchers had never scientifically documented this behavior before, and the observation offers potential proof for a 53-year-old theory. Baleen whales are often thought of as solitary — islands unto themselves. However, some scientists believe they travel in diffuse herds, communicating over hundreds of kilometers. Legendary biologist Roger Payne and oceanographer Douglas Webb first floated the concept of acoustic herd theory (or should it be heard theory?) in 1971. This story is from Hakai Magazine, an online publication about science and society in coastal ecosystems, and is republished here with permission. Payne, who helped discover and record humpback whale song a few years prior, was struck by the fact that many toothed cetaceans such as killer whales and dolphins are highly social and move together in tight-knit family groups. These bands provide safety from predators and allow the animals to raise their young communally. Payne speculated that the larger baleen whales might travel in groups, too, but on a broader geographic scale. And perhaps the behemoths signaled acoustically to keep in touch across vast distances. Webb and Payne’s original paper on acoustic herd theory demonstrated that fin whale vocalizations — low-frequency sounds that carry long distances — could theoretically travel an astonishing 700 kilometers (over 400 miles) in certain areas of the ocean. However, it’s been easier to show that a whale is making a call than to prove the recipient is a fellow cetacean hundreds of kilometers away, says Susan Parks, a behavioral ecologist at Syracuse University in New York who studies animal acoustics.

Keyword: Animal Communication; Evolution
Link ID: 29502 - Posted: 10.02.2024

By Katarina Zimmer If we could talk with whales, should we? When scientists in Alaska recently used pre-recorded whale sounds to engage in a 20-minute back-and-forth with a local humpback whale, some hailed it as the first “conversation” with the cetaceans. But the interaction between an underwater speaker mounted on the research boat and the whale, which was described last year in the journal PeerJ, also stimulated a broader discussion around the ethics of communicating with other species. After the whale circled the boat for a while, the puffs from her blowhole sounded wheezier than usual, suggesting to the scientists aboard that she was aroused in some way—perhaps curious, frustrated, or bored. Nevertheless, Twain—as scientists had nicknamed her—continued to respond to the speaker’s calls until they stopped. Twain called back three more times, but the speaker on the boat had fallen silent. She swam away. Scientists have used recorded calls to study animal behavior and communication for decades. But new efforts—and technology such as artificial intelligence—are striving not just to deafly mimic animal communication, but also to more deeply understand it. And while the potential extension of this research that has most captured public excitement—producing our own coherent whale sounds and meaningfully communicating with them—is still firmly in the realm of science fiction, this kind of research might just bring us a small step closer. The work to decipher whale vocalizations was inspired by the research on humpback whale calls by the biologist Roger Payne and played an important role in protecting the species. In the 1960s, Payne discovered that male humpbacks sing—songs so intricate and powerful it was hard to imagine they have no deeper meaning. His album of humpback whale songs became an anthem to the “Save the Whales” movement and helped motivate the creation of the Marine Mammal Protection Act in 1972 in the United States. © 2024 NautilusNext Inc.,

Keyword: Animal Communication; Evolution
Link ID: 29501 - Posted: 10.02.2024

By Shaena Montanari Sea robins skitter across the sea floor with six tiny fins-turned-legs. And at least one species of these bottom feeders is exceptionally skilled at digging up food—so good that other fishes follow these sea robins to snatch up leftover snacks. The sea robins owe this talent to their legs, according to a pair of studies published today in Current Biology. The new work shows that the appendages evolved a specialized sensory system to feel and taste hidden prey. The legs of one common species, for example, are innervated by touch-sensitive neurons and dotted with tiny papillae that express taste receptors. “It’s just really neat to see the molecular components that nature is using to spin out not only new structures, but also new behaviors,” says David Kingsley, professor of developmental biology at Stanford University and an investigator on both studies. The results formalize work from the 1960s and ’70s that first indicated the special chemosensory abilities of sea robins, says Tom Finger, professor of cell and developmental biology at the University of Colorado Anschutz Medical Campus, who was not involved in the new studies. This is “a major, important contribution to show that taste receptors have become expressed in the specialized sensory organ.” This finding “demonstrates, I think, an evolutionary principle, which is that evolution uses the tool kit that’s in place and then just slightly changes it,” says Nicholas Bellono, professor of molecular and cellular biology at Harvard University, who is an investigator on both new studies and also researches unique senses in cephalopods. Last year, he and his colleagues described a similar adaptation in octopuses: “They took this receptor that was for neurotransmission and then just repurposed it with a slight tinkering to now be a sensory receptor. So it’s sort of a theme we keep seeing repeat across the diversity of life.” © 2024 Simons Foundation

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 29500 - Posted: 10.02.2024

By Emily Anthes The common marmoset is a certified chatterbox. The small, South American monkey uses an array of chirps, whistles and trills to defend its territory, flag the discovery of food, warn of impending danger and find family members hidden by dense forest foliage. Marmosets also use distinct calls to address different individuals, in much the same way that people use names, new research suggests. The findings make them the first nonhuman primates known to use name-like vocal labels for individuals. Until this year, only humans, dolphins and parrots were known to use names when communicating. In June, however, scientists reported that African elephants appeared to use names, too; researchers made the discovery by using artificial intelligence-powered software to detect subtle patterns in the elephants’ low-pitched rumbles. In the new study, which was published in Science last month, a different team of researchers also used A.I. to uncover name-like labels hiding in the calls of common marmosets. The discovery, which is part of a burgeoning scientific effort to use sophisticated computational tools to decode animal communication, could help shed light on the origins of language. And it raises the possibility that name-bestowing behavior may be more widespread in the animal kingdom than scientists once assumed. “I think what it’s telling us is that it’s likely that animals actually have names for each other a lot more than maybe we ever conceived,” said George Wittemyer, a conservation biologist at Colorado State University who led the recent elephant study but was not involved in the marmoset research. “We just never were really looking properly.” Marmosets are highly social, forming long-term bonds with their mates and raising their offspring cooperatively in small family groups. They produce high-pitched, whistle-like “phee calls” to communicate with other marmosets who might be hidden among the treetops. “They start to exchange phee calls when they lose eyesight of each other,” said David Omer, a neuroscientist at the Hebrew University of Jerusalem who led the new study. © 2024 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 29480 - Posted: 09.14.2024

By Carl Zimmer The human brain, more than any other attribute, sets our species apart. Over the past seven million years or so, it has grown in size and complexity, enabling us to use language, make plans for the future and coordinate with one another at a scale never seen before in the history of life. But our brains came with a downside, according to a study published on Wednesday. The regions that expanded the most in human evolution became exquisitely vulnerable to the ravages of old age. “There’s no free lunch,” said Sam Vickery, a neuroscientist at the Jülich Research Center in Germany and an author of the study. The 86 billion neurons in the human brain cluster into hundreds of distinct regions. For centuries, researchers could recognize a few regions, like the brainstem, by hallmarks such as the clustering of neurons. But these big regions turned out to be divided into smaller ones, many of which were revealed only with the help of powerful scanners. As the structure of the human brain came into focus, evolutionary biologists became curious about how the regions evolved from our primate ancestors. (Chimpanzees are not our direct ancestors, but both species descended from a common ancestor about seven million years ago.) The human brain is three times as large as that of chimpanzees. But that doesn’t mean all of our brain regions expanded at the same pace, like a map drawn on an inflating balloon. Some regions expanded only a little, while others grew a lot. Dr. Vickery and his colleagues developed a computer program to analyze brain scans from 189 chimpanzees and 480 humans. Their program mapped each brain by recognizing clusters of neurons that formed distinct regions. Both species had 17 brain regions, the researchers found. © 2024 The New York Times Company

Keyword: Development of the Brain; Evolution
Link ID: 29459 - Posted: 08.31.2024