Chapter 6. Evolution of the Brain and Behavior

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By Sonia Shah Can a mouse learn a new song? Such a question might seem whimsical. Though humans have lived alongside mice for at least 15,000 years, few of us have ever heard mice sing, because they do so in frequencies beyond the range detectable by human hearing. As pups, their high-pitched songs alert their mothers to their whereabouts; as adults, they sing in ultrasound to woo one another. For decades, researchers considered mouse songs instinctual, the fixed tunes of a windup music box, rather than the mutable expressions of individual minds. But no one had tested whether that was really true. In 2012, a team of neurobiologists at Duke University, led by Erich Jarvis, a neuroscientist who studies vocal learning, designed an experiment to find out. The team surgically deafened five mice and recorded their songs in a mouse-size sound studio, tricked out with infrared cameras and microphones. They then compared sonograms of the songs of deafened mice with those of hearing mice. If the mouse songs were innate, as long presumed, the surgical alteration would make no difference at all. Jarvis and his researchers slowed down the tempo and shifted the pitch of the recordings, so that they could hear the songs with their own ears. Those of the intact mice sounded “remarkably similar to some bird songs,” Jarvis wrote in a 2013 paper that described the experiment, with whistlelike syllables similar to those in the songs of canaries and the trills of dolphins. Not so the songs of the deafened mice: Deprived of auditory feedback, their songs became degraded, rendering them nearly unrecognizable. They sounded, the scientists noted, like “squawks and screams.” Not only did the tunes of a mouse depend on its ability to hear itself and others, but also, as the team found in another experiment, a male mouse could alter the pitch of its song to compete with other male mice for female attention. Inside these murine skills lay clues to a puzzle many have called “the hardest problem in science”: the origins of language. In humans, “vocal learning” is understood as a skill critical to spoken language. Researchers had already discovered the capacity for vocal learning in species other than humans, including in songbirds, hummingbirds, parrots, cetaceans such as dolphins and whales, pinnipeds such as seals, elephants and bats. But given the centuries-old idea that a deep chasm separated human language from animal communications, most scientists understood the vocal learning abilities of other species as unrelated to our own — as evolutionarily divergent as the wing of a bat is to that of a bee. The apparent absence of intermediate forms of language — say, a talking animal — left the question of how language evolved resistant to empirical inquiry. © 2023 The New York Times Company

Keyword: Language; Animal Communication
Link ID: 28921 - Posted: 09.21.2023

COMIC: When, why and how did neurons first evolve? Scientists are piecing together the ancient story. By Tim Vernimmen Illustrated by Maki Naro 09.14.2023 © 2023 Annual Reviews

Keyword: Evolution; Development of the Brain
Link ID: 28920 - Posted: 09.21.2023

By Kenneth S. Kosik Before our evolutionary ancestors had a brain—before they had any organs—18 different cell types got together to make a sea sponge. Remarkably, some of these cells had many of the genes needed to make a brain, even though the sponge has neither neurons nor a brain. In my neuroscience lab at the University of California, Santa Barbara, my colleagues and collaborators discovered this large repository of brain genes in the sponge. Ever since, we have asked ourselves why this ancient, porous blob of cells would contain a set of neural genes in the absence of a nervous system? What was evolution up to? The sea sponge first shows up in the fossil record about 600 million years ago. They live at the bottom of the ocean and are immobile, passive feeders. In fact, early biologists thought they were plants. Often encased by a hard exterior, a row of cells borders a watery center. Each cell has a tiny cilium that gently circulates a rich flow of microorganisms on which they feed. This seemingly simple organization belies a giant step in evolution. For the previous 3 billion years, single-celled creatures inhabited the planet. In one of evolution’s most creative acts, independent cells joined together, first into a colony and later into a truly inseparable multicellular organism. Colonies of single cells offered the first inkling that not every cell in the colony had to be identical. Cells in the interior might differ subtly from those on the periphery that are subject to the whims of the environment. Colonies offered the advantages of cooperation among many nearly identical cells. The next evolutionary innovation, multicellularity, broke radically from the past. © 2023 NautilusNext Inc.,

Keyword: Evolution
Link ID: 28913 - Posted: 09.16.2023

By Darren Incorvaia By now, it’s no secret that the phrase “bird brain” should be a compliment, not an insult. Some of our feathered friends are capable of complex cognitive tasks, including tool use (SN: 2/10/23). Among the brainiest feats that birds are capable of is vocal learning, or the ability to learn to mimic sounds and use them to communicate. In birds, this leads to beautiful calls and songs; in humans, it leads to language. The best avian vocal learners, such as crows and parrots, also tend to be considered the most intelligent birds. So it’s natural to think that the two traits could be linked. But studies with smart birds have found conflicting evidence. Although vocal learning may be linked with greater cognitive capacity in some species, the opposite relationship seems to hold true in others. Now, a massive analysis of 214 birds from 23 species shows that there is indeed a link between vocal learning and at least one advanced cognitive ability — problem-solving. The study, described in the Sept. 15 Science, is the first to analyze multiple bird species instead of just one. More than 200 birds from 23 species were given different cognitive tests to gauge their intelligence. One of the problem-solving tasks asked birds to pull a cork lid off a glass flask to access a tasty treat (bottom left). Comparing these tests with birds’ ability to learn songs and calls showed that the better vocal learners are also better at problem-solving. To compare species, biologist Jean-Nicolas Audet of the Rockefeller University in New York City and colleagues had to devise a way to assess all the birds’ vocal learning and cognitive abilities. © Society for Science & the Public 2000–2023.

Keyword: Intelligence; Evolution
Link ID: 28912 - Posted: 09.16.2023

By Sarah Lyall The author Cat Bohannon was a preteen in Atlanta in the 1980s when she saw the film “2001: A Space Odyssey” for the first time. As she took in its famous opening scene, in which a bunch of apes picks up a bunch of bones and quickly begins using them to hit each other, Bohannon was struck by the sheer maleness of the moment. “I thought, ‘Where are the females in this story?’” Bohannon said recently, imagining what those absent females might have been up to at that particular time. “It’s like, ‘Oh, sorry, I see you’re doing something really important with a rock. I’m just going to go over there behind that hill and quietly build the future of the species in my womb.” That realization was just one of what Bohannon, 44, calls “a constellation of moments” that led her to write her new book, “Eve: How the Female Body Drove 200 Million Years of Human Evolution.” A page-turning whistle-stop tour of mammalian development that begins in the Jurassic Era, “Eve” recasts the traditional story of evolutionary biology by placing women at its center. The idea is that by examining how women evolved differently from men, Bohannon argues, we can “provide the latest answers to women’s most basic questions about their bodies.” These include, she says: Why do women menstruate? Why do they live longer? And what is the point of menopause? These are timely questions. Thanks to regulations established in the 1970s, clinical trials in the United States have typically used mostly male subjects, from mice to humans. (This is known as “the male norm.”) Though that changed somewhat in 1994, when the National Institutes of Health updated its rules, even the new protocols are replete with loopholes. For example: “From 1996 to 2006, more than 79 percent of animal studies published in the scientific journal Pain included only male subjects,” she writes. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28907 - Posted: 09.13.2023

By Ann Gibbons Go to the Democratic Republic of the Congo, and you’re unlikely to encounter chimps so plump they have trouble climbing trees or vervet monkeys so chubby they huff and puff as they swing from branch to branch. Humans are a different story. Walk down a typical U.S. street and almost half of the people you encounter are likely to have obesity. Scientists have long blamed our status as the “fattest primate” on genes that help us store fat more efficiently or diets overloaded with sugars or fat. But a new study of 40 species of nonhuman primates, ranging from tiny mouse lemurs to hulking gorillas, finds many pack on the pounds just as easily as we do, regardless of diet, habitat, or genetic differences. All they need is extra food. “Lots of primates put on too much weight, the same as humans,” says Herman Pontzer, a biological anthropologist at Duke University and author of the new study, published this week in the Philosophical Transactions of the Royal Society B. “Humans are not special.” Some researchers have suggested our species is prone to obesity because our ancestors evolved to be incredibly efficient at storing calories. The adaptation would have helped our ancient relatives, who often faced famine after the transition to agriculture, get through lean times. This selection pressure for so-called thrifty genes set us apart from other primates, the thinking goes. But other primates can get fat. Kanzi, the first ape to show he understands spoken English, was triple the average weight of his bonobo species after years of being rewarded with bananas, peanuts, and other treats during research; scientists eventually put him on a diet. And then there was Uncle Fatty, an obese macaque who lived on the streets of Bangkok where tourists fed him milkshakes, noodles, and other junk food. He weighed an astonishing 15 kilograms—three times more than the average macaque—before he went to the monkey equivalent of a fat farm. © 2023 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 28902 - Posted: 09.10.2023

By Carolyn Wilke Young jumping spiders dangle by a thread through the night, in a box, in a lab. Every so often, their legs curl and their spinnerets twitch — and the retinas of their eyes, visible through their translucent exoskeletons, shift back and forth. “What these spiders are doing seems to be resembling — very closely — REM sleep,” says Daniela Rößler, a behavioral ecologist at the University of Konstanz in Germany. During REM (which stands for rapid eye movement), a sleeping animal’s eyes dart about unpredictably, among other features. In people, REM is when most dreaming happens, particularly the most vivid dreams. Which leads to an intriguing question. If spiders have REM sleep, might dreams also unfold in their poppy-seed-size brains? Rößler and her colleagues reported on the retina-swiveling spiders in 2022. Training cameras on 34 spiders, they found that the creatures had brief REM-like spells about every 17 minutes. The eye-darting behavior was specific to these bouts: It didn’t happen at times in the night when the jumping spiders stirred, stretched, readjusted their silk lines or cleaned themselves with a brush of a leg. Though the spiders are motionless in the run-up to these REM-like bouts, the team hasn’t yet proved that they are sleeping. But if it turns out that they are — and if what looks like REM really is REM — dreaming is a distinct possibility, Rößler says. She finds it easy to imagine that jumping spiders, as highly visual animals, might benefit from dreams as a way to process information they took in during the day. Young jumping spiders have translucent skin. Behind their eyes, tube-shaped retinas move as the spiderlings look about. As shown in this sped-up video, researchers have also observed such retinal tube-shifting behavior in resting — possibly sleeping — spiders. In these intermittent, active bouts, the animals’ legs curl and their spinnerets twitch — suggesting that spiders may experience something like REM sleep. © 2023 Annual Reviews

Keyword: Sleep; Evolution
Link ID: 28896 - Posted: 09.07.2023

By Jori Lewis The squat abandoned concrete structure may have been a water tower when this tract of land in the grasslands of Mozambique was a cotton factory. Now it served an entirely different purpose: Housing a bat colony. To climb through the building’s low opening, bat researcher Césaria Huó and I had to battle a swarm of biting tsetse flies and clear away a layer of leaves and vines. My eyes quickly adjusted to the low light, but my nose, even behind a mask, couldn’t adjust to the smell of hundreds of bats and layers of bat guano—a fetid reek of urea with fishy, spicy overtones. But Huó had a different reaction. “I don’t mind the smell now,” she said. After several months of monitoring bat colonies in the Gorongosa National Park area as a master’s student in the park’s conservation biology program, Huó said she almost likes it. “Now, when I smell it, I know there are bats here.” Since we arrived at the tower during the daylight hours, I had expected the nocturnal mammals to be asleep. Instead, they were shaking their wings, flying from one wall or spot on the ceiling to another, swooping sometimes a bit too close to me for my comfort. But the bats didn’t care about me; they were cruising for mates. It was mating season, and we had lucked out to see their mating performances. Huó pointed out that some females were inspecting the males, checking out their wing flapping prowess. But Huó and her adviser, the polymath entomologist Piotr Naskrecki, did not bring me to this colony to view the bats’ seductive dances and their feats of flight, since those behaviors are already known to scientists. We were here to decipher what the bats were saying while doing them. Huó and Naskrecki had set up cameras and audio recorders the night before to learn more about these bats and try to understand the nature of the calls they use, listening for signs of meaning. © 2023 NautilusNext Inc., All rights reserved.

Keyword: Animal Communication; Evolution
Link ID: 28895 - Posted: 09.07.2023

By David Grimm Apart from Garfield’s legendary love of lasagna, perhaps no food is more associated with cats than tuna. The dish is a staple of everything from The New Yorker cartoons to Meow Mix jingles—and more than 6% of all wild-caught fish goes into cat food. Yet tuna (or any seafood for that matter) is an odd favorite for an animal that evolved in the desert. Now, researchers say they have found a biological explanation for this curious craving. In a study published this month in Chemical Senses, scientists report that cat taste buds contain the receptors needed to detect umami—the savory, deep flavor of various meats, and one of the five basic tastes in addition to sweet, sour, salty, and bitter. Indeed, umami appears to be the primary flavor cats seek out. That’s no surprise for an obligate carnivore. But the team also found these cat receptors are uniquely tuned to molecules found at high concentrations in tuna, revealing why our feline friends seem to prefer this delicacy over all others. “This is an important study that will help us better understand the preferences of our familiar pets,” says Yasuka Toda, a molecular biologist at Meiji University and a leader in studying the evolution of umami taste in mammals and birds. The work could help pet food companies develop healthier diets and more palatable medications for cats, says Toda, who was not involved with the industry-funded study. Cats have a unique palate. They can’t taste sugar because they lack a key protein for sensing it. That’s probably because there’s no sugar in meat, says Scott McGrane, a flavor scientist and research manager for the sensory science team at the Waltham Petcare Science Institute, which is owned by pet food–maker Mars Petcare UK. There’s a saying in evolution, he says: “If you don’t use it, you lose it.” Cats also have fewer bitter taste receptors than humans do—a common trait in uber-carnivores. But cats must taste something, McGrane reasoned, and that something is likely the savory flavor of meat. In humans and many other animals, two genes—Tas1r1 and Tas1r3—encode proteins that join together in taste buds to form a receptor that detects umami. Previous work had shown that cats express the Tas1r3 gene in their taste buds, but it was unclear whether they had the other critical puzzle piece.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28885 - Posted: 08.26.2023

Jon Hamilton Scientists have genetically engineered a squid that is almost as transparent as the water it's in. The squid will allow researchers to watch brain activity and biological processes in a living animal. Sponsor Message ARI SHAPIRO, HOST: For most of us, it would take magic to become invisible, but for some lucky, tiny squid, all it took was a little genetic tweaking. As part of our Weekly Dose of Wonder series, NPR's Jon Hamilton explains how scientists created a see-through squid. JON HAMILTON, BYLINE: The squid come from the Marine Biological Laboratory in Woods Hole, Mass. Josh Rosenthal is a senior scientist there. He says even the animal's caretakers can't keep track of them. JOSH ROSENTHAL: They're really hard to spot. We know we put it in this aquarium, but they might look for a half-hour before they can actually see it. They're that transparent. HAMILTON: Almost invisible. Carrie Albertin, a fellow at the lab, says studying these creatures has been transformative. CARRIE ALBERTIN: They are so strikingly see-through. It changes the way you interpret what's going on in this animal, being able to see completely through the body. HAMILTON: Scientists can watch the squid's three hearts beating in synchrony or see its brain cells at work. And it's all thanks to a gene-editing technology called CRISPR. A few years ago, Rosenthal and Albertin decided they could use CRISPR to create a special octopus or squid for research. ROSENTHAL: Carrie and I are highly biased. We both love cephalopods - right? - and we have for our entire careers. HAMILTON: So they focused on the hummingbird bobtail squid. It's smaller than a thumb and shaped like a dumpling. Like other cephalopods, it has a relatively large and sophisticated brain. Rosenthal takes me to an aquarium to show me what the squid looks like before its genes are altered. ROSENTHAL: Here is our hummingbird bobtail squid. You can see him right there in the bottom, just kind of sitting there hunkered down in the sand. At night, it'll come out and hunt and be much more mobile. © 2023 npr

Keyword: Brain imaging; Evolution
Link ID: 28883 - Posted: 08.26.2023

By Veronique Greenwood Floating languorously through forests and jungles of the Americas, longwing butterflies have many secrets. The 30-odd species in this group include many mimics. The wing markings on some distantly related species of longwings are so similar they inspired one Victorian naturalist to theorize that harmless species could mimic deadly ones to avoid predators. In the age of genomic sequencing, biologists have found other oddities in longwings. In a paper published last week in the Proceedings of the National Academy of Sciences, researchers report that female zebra longwings can see colors that males cannot, thanks to a gene on their sex chromosome. Understanding how it got there might shed light on how differences between sexes can evolve. Like primates, butterflies have a handful of proteins that are sensitive to certain wavelengths of light that, working together, produce the ability to distinguish colors. Curious about the zebra longwing’s vision, Adriana Briscoe, a professor at the University of California, Irvine, and an author of the new paper, asked a student to check the species’ genome for a well-known color vision gene. The gene, known as UVRh1, codes for a protein that is sensitive to ultraviolet light. To her surprise, it was nowhere to be found. Digging deeper, and drawing on genomic data from additional zebra longwings, Dr. Briscoe and her colleagues discovered that UVRh1 was there, but only in females. With lab experiments, they confirmed that females could see markings males couldn’t. They eventually pinpointed the gene in an unexpected place: the butterfly’s tiny sex chromosome. Sex chromosomes in butterflies are unstable, often shedding genes that are picked up by other chromosomes, or lost entirely, Dr. Briscoe said. That makes them a somewhat unusual place to keep something as important as a gene for color vision. © 2023 The New York Times Company

Keyword: Sexual Behavior; Vision
Link ID: 28872 - Posted: 08.19.2023

By Elizabeth Preston Some things need no translation. No matter what language you speak, you can probably recognize a fellow human who is cheering in triumph or swearing in anger. If you are a crocodile, you may recognize the sound of a young animal crying in distress, even if that animal is a totally different species — like, say, a human baby. That sound means you are close to a meal. In a study published Wednesday in Proceedings of the Royal Society B, researchers put speakers near crocodiles and played recordings of human, bonobo and chimpanzee infants. The crocodiles were attracted to the cries, especially shrieks that sounded more distressed. “That means that distress is something that is shared by species that are really, really distant,” said Nicolas Grimault, a bioacoustic research director at the French National Centre for Scientific Research and one of the paper’s authors. “You have some kind of emotional communication between crocodiles and humans.” These infant wails most likely drew crocodiles because they signaled an easy meal nearby, the authors say. But in some cases, the opposite may have been true: The crocs were trying to help. The animals in the study were Nile crocodiles, African predators that can reach up to 18 feet long. Understandably, the researchers kept their distance. They visited the reptiles at a Moroccan zoo and placed remote-controlled loudspeakers on the banks of outdoor ponds. The researchers played recordings of cries from those speakers while groups of up to 25 crocodiles were nearby. Some cries came from infant chimpanzees or bonobos calling to their mothers. Others were human babies, recorded either at bath time or in the doctor’s office during a vaccination. Nearly all of the recordings prompted some crocodiles to look or to move toward the speaker. When they heard the sounds of human babies getting shots, for example, almost half the crocodiles in a group responded. Dr. Grimault said the reptiles seemed most tempted by cries with a harsh quality that other studies have linked to distress in mammals. © 2023 The New York Times Company

Keyword: Hearing; Evolution
Link ID: 28871 - Posted: 08.09.2023

By Alla Katsnelson Our understanding of animal minds is undergoing a remarkable transformation. Just three decades ago, the idea that a broad array of creatures have individual personalities was highly suspect in the eyes of serious animal scientists — as were such seemingly fanciful notions as fish feeling pain, bees appreciating playtime and cockatoos having culture. Today, though, scientists are rethinking the very definition of what it means to be sentient and seeing capacity for complex cognition and subjective experience in a great variety of creatures — even if their inner worlds differ greatly from our own. Such discoveries are thrilling, but they probably wouldn’t have surprised Charles Henry Turner, who died a century ago, in 1923. An American zoologist and comparative psychologist, he was one of the first scientists to systematically probe complex cognition in animals considered least likely to possess it. Turner primarily studied arthropods such as spiders and bees, closely observing them and setting up trailblazing experiments that hinted at cognitive abilities more complex than most scientists at the time suspected. Turner also explored differences in how individuals within a species behaved — a precursor of research today on what some scientists refer to as personality. Most of Turner’s contemporaries believed that “lowly” critters such as insects and spiders were tiny automatons, preprogrammed to perform well-defined functions. “Turner was one of the first, and you might say should be given the lion’s share of credit, for changing that perception,” says Charles Abramson, a comparative psychologist at Oklahoma State University in Stillwater who has done extensive biographical research on Turner and has been petitioning the US Postal Service for years to issue a stamp commemorating him. Turner also challenged the views that animals lacked the capacity for intelligent problem-solving and that they behaved based on instinct or, at best, learned associations, and that individual differences were just noisy data. But just as the scientific establishment of the time lacked the imagination to believe that animals other than human beings can have complex intelligence and subjectivity of experience, it also lacked the collective imagination to envision Turner, a Black scientist, as an equal among them. The hundredth anniversary of Turner’s death offers an opportunity to consider what we may have missed out on by their oversight. © 2023 Annual Reviews

Keyword: Learning & Memory; Evolution
Link ID: 28869 - Posted: 08.09.2023

By Simon Makin Rats are extremely playful creatures. They love playing chase, and they literally jump for joy when tickled. Central to this playfulness, a new study finds, are cells in a specific region of rats’ brains. Neurons in the periaqueductal gray, or PAG, are active in rats during different kinds of play, scientists report July 28 in Neuron. And blocking the activity of those neurons makes the rodents much less playful. The results give insight into a poorly understood behavior, particularly in terms of how play is controlled in the brain. “There are prejudices that it’s childish and not important, but play is an underrated behavior,” says Michael Brecht, a neuroscientist at Humboldt University in Berlin. Scientists think play helps animals develop resilience. Some even relate it to optimal functioning. “When you’re playing, you’re being your most creative, thoughtful, interactive self,” says Jeffrey Burgdorf, a neuroscientist at Northwestern University in Evanston, Ill., who was not involved in the new study. This is the opposite of depressive states, and Burgdorf’s own research aims to turn understanding the neuroscience of play into new therapies for mood disorders. For the new study, Brecht and colleagues got rats used to lab life and being tickled and played with in a game of chase-the-hand. When rats play, they squeal with glee at a frequency of 50 kilohertz, which humans can’t hear. The researchers recorded these ultrasonic giggles as a way of measuring when the rats were having fun. To explore how a specific brain region in rats might relate to their well-documented play behavior, researchers tickled rats on their bellies and backs and played chase-the-hand. Rats also played together, chasing and play-fighting. Ultrasonic giggles, processed to make them audible to humans, coordinate social play and show that the rats are having fun. © Society for Science & the Public 2000–2023.

Keyword: Emotions; Evolution
Link ID: 28864 - Posted: 08.02.2023

By Alejandra Manjarrez Rafael Jiménez Medina learned how to hunt elusive Iberian moles in the fields of southern Spain in the 1980s, when he was a young PhD student in genetics at the University of Granada. A local hunter of the moles (Talpa occidentalis) taught him how to capture these solitary, aggressive and territorial animals. The moles dig subterranean galleries and labyrinths in the meadows of the Iberian Peninsula, especially those with soft soils rich in earthworms, their favorite food. Such activity can benefit the soil — by aerating or mixing it — but the moles’ presence and constant movement in cultivated land raise the ire of farmers, who pay hunters to get rid of them. Jiménez Medina had a different motivation for hunting these subterranean mammals. His doctoral project was to visualize and analyze their chromosomes, which meant collecting, preparing and examining samples from the testes of males. His lab analyses led to a curious finding: Some of the moles he had identified as males were in fact genetically females — that is, their sex chromosomes were XX (female) and not XY (male). The confusion, we now know, stems from the unusual composition of the reproductive organs of female moles. In contrast to most female mammals, which have only ovaries, female Iberian moles also have testicular tissue. This tissue anatomically resembles male testicles but differs in that it produces testosterone but no sperm. The female mole’s organs are composed of both an ovarian and a testicular portion and are known as ovotestes. In addition, female moles have a clitoris covered with a foreskin and with an elongated appearance that resembles a penis; they urinate through this structure. Another unique anatomical feature is that during these females’ juvenile stage, the vaginal orifice remains closed. © 2023 Annual Reviews

Keyword: Sexual Behavior; Evolution
Link ID: 28849 - Posted: 07.19.2023

By McKenzie Prillaman When speaking to young kids, humans often use squeaky, high-pitched baby talk. It turns out that some dolphins do, too. Bottlenose dolphin moms modify their individually distinctive whistles when their babies are nearby, researchers report June 26 in the Proceedings of the National Academy of Sciences. This “parentese” might enhance attention, bonding and vocal learning in calves, as it seems to do in humans. During the first few months of life, each common bottlenose dolphin (Tursiops truncatus) develops a unique tune, or signature whistle, akin to a name (SN: 7/22/13). The dolphins shout out their own “names” in the water “likely as a way to keep track of each other,” says marine biologist Laela Sayigh of the Woods Hole But dolphin moms seem to tweak that tune in the presence of their calves, which tend to stick by mom’s side for three to six years. It’s a change that Sayigh first noticed in a 2009 study published by her student. But “it was just one little piece of this much larger study,” she says. To follow up on that observation, Sayigh and colleagues analyzed signature whistles from 19 female dolphins both with and without their babies close by. Audio recordings were captured from a wild population that lives near Sarasota Bay, Fla., during catch-and-release health assessments that occurred from 1984 to 2018. The researchers examined 40 instances of each dolphin’s signature whistle, verified by the unique way each vocalization’s frequencies change over time. Half of each dolphin’s whistles were voiced in the presence of her baby. When youngsters were around, the moms’ whistles contained, on average, a higher maximum and slightly lower minimum pitch compared with those uttered in the absence of calves, contributing to an overall widened pitch range. © Society for Science & the Public 2000–2023.

Keyword: Language; Animal Communication
Link ID: 28835 - Posted: 06.28.2023

Kerri Smith In a dimly lit laboratory in London, a brown mouse explores a circular tabletop, sniffing as it ambles about. Suddenly, silently, a shadow appears. In a split second, the mouse’s brain whirs with activity. Neurons in its midbrain start to fire, sensing the threat of a potential predator, and a cascade of activity in an adjacent region orders its body to choose a response — freeze to the spot in the hope of going undetected, or run for shelter, in this case a red acetate box stationed nearby. From the mouse’s perspective, this is life or death. But the shadow wasn’t cast by a predator. Instead, it is the work of neuroscientists in Tiago Branco’s lab, who have rigged up a plastic disc on a lever to provoke, and thereby study, the mouse’s escape behaviour. This is a rapid decision-making process that draws on sensory information, previous experience and instinct. Branco, a neuroscientist at the Sainsbury Wellcome Centre at University College London, has wondered about installing a taxidermied owl on a zip wire to create a more realistic experience. And his colleagues have more ideas — cutting the disc into a wingspan shape, for instance. “Having drones — that would also be very nice,” says Dario Campagner, a researcher in Branco’s lab. A mouse detects a looming threat and runs for cover. The shadow has been darkened. The set-up is part of a growing movement to step away from some of the lab experiments that neuroscientists have used for decades to understand the brain and behaviour. Such exercises — training an animal to use a lever or joystick to get a reward, for example, or watching it swim through a water maze — have established important principles of brain activity and organization. But they take days to months of training an animal to complete specific, idiosyncratic tasks. The end result, Branco says, is like studying a “professional athlete”; the brain might work differently in the messy, unpredictable real world. Mice didn’t evolve to operate a joystick. Meanwhile, many behaviours that come naturally — such as escaping a predator, or finding scarce food or a receptive mate — are extremely important for the animal, says Ann Kennedy, a theoretical neuroscientist at Northwestern University in Chicago, Illinois. They are “critical to survival, and under selective pressure”, she says. By studying these natural actions, scientists are hoping to glean lessons about the brain and behaviour that are more holistic and more relevant to everyday activity than ever before.

Keyword: Learning & Memory; Evolution
Link ID: 28822 - Posted: 06.14.2023

By Marlowe Starling When a bird sings, you may think you’re hearing music. But are the melodies it’s making really music? Or is what we’re hearing merely a string of lilting calls that appeals to the human ear? Birdsong has inspired musicians from Bob Marley to Mozart and perhaps as far back as the first hunter-gatherers who banged out a beat. And a growing body of research is showing that the affinity human musicians feel toward birdsong has a strong scientific basis. Scientists are understanding more about avian species’ ability to learn, interpret and produce songs much like our own. Just like humans, birds learn songs from each other and practice to perfect them. And just as human speech is distinct from human music, bird calls, which serve as warnings and other forms of direct communication, differ from birdsong. While researchers are still debating the functions of birdsong, studies show that it is structurally similar to our own tunes. So, are birds making music? That depends on what you mean. “I’m not sure we can or want to define music,” said Ofer Tchernichovski, a zoologist and psychologist at the City University of New York who studies birdsong. Where you draw the line between music and mere noise is arbitrary, said Emily Doolittle, a zoomusicologist and composer at the Royal Conservatoire of Scotland. The difference between a human baby’s babbling versus a toddler’s humming might seem more distinct than that of a hatchling’s cry for food and a maturing bird’s practicing of a melody, she added. Wherever we draw the line, birdsong and human song share striking similarities. How birds build songs Existing research points to one main conclusion: Birdsong is structured like human music. Songbirds change their tempo (speed), pitch (how high or low they sing) and timbre (tone) to sing tunes that resemble our own melodies. © 2023 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 28817 - Posted: 06.07.2023

by Adam Kirsch Giraffes will eat courgettes if they have to, but they really prefer carrots. A team of researchers from Spain and Germany recently took advantage of this preference to investigate whether the animals are capable of statistical reasoning. In the experiment, a giraffe was shown two transparent containers holding a mixture of carrot and courgette slices. One container held mostly carrots, the other mostly courgettes. A researcher then took one slice from each container and offered them to the giraffe with closed hands, so it couldn’t see which vegetable had been selected. In repeated trials, the four test giraffes reliably chose the hand that had reached into the container with more carrots, showing they understood that the more carrots were in the container, the more likely it was that a carrot had been picked. Monkeys have passed similar tests, and human babies can do it at 12 months old. But giraffes’ brains are much smaller than primates’ relative to body size, so it was notable to see how well they grasped the concept. Such discoveries are becoming less surprising every year, however, as a flood of new research overturns longstanding assumptions about what animal minds are and aren’t capable of. A recent wave of popular books on animal cognition argue that skills long assumed to be humanity’s prerogative, from planning for the future to a sense of fairness, actually exist throughout the animal kingdom – and not just in primates or other mammals, but in birds, octopuses and beyond. In 2018, for instance, a team at the University of Buenos Aires found evidence that zebra finches, whose brains weigh half a gram, have dreams. Monitors attached to the birds’ throats found that when they were asleep, their muscles sometimes moved in exactly the same pattern as when they were singing out loud; in other words, they seemed to be dreaming about singing. © 2023 Guardian News & Media Limited

Keyword: Evolution; Learning & Memory
Link ID: 28808 - Posted: 05.31.2023

By Carolyn Wilke Costello the octopus was napping while stuck to the glass of his tank at the Rockefeller University in New York. He snoozed quietly for half an hour, and then entered a more active sleep stage, his skin cycling through colors and textures used for camouflage — typical behavior for a cephalopod. But soon things became strange. A minute later, Costello scuttled along the glass toward his tank’s sandy bottom, curling his arms over his body. Then he spun like a writhing cyclone. Finally, Costello swooped down and clouded half of his tank with ink. As the tank’s filtration system cleared the ink, Eric Angel Ramos, a marine scientist, noticed that Costello was grasping a pipe with unusual intensity, “looking like he was trying to kill it,” he said. “This was not a normal octopus behavior,” said Dr. Ramos, who is now at the University of Vermont. It’s not clear when or if Costello woke up during the episode, Dr. Ramos said. But afterward, Costello returned to normal, eating and later playing with his toys. “We were completely dumbfounded,” said Marcelo O. Magnasco, a biophysicist at Rockefeller. Perhaps Costello was having a nightmare, he and a team of researchers speculated. They shared this idea and other possible explanations in a study uploaded this month to the bioRxiv website. It has yet to be formally reviewed by other scientists. After the incident, Dr. Ramos reviewed the footage of Costello’s activity, which was recorded as part of a behavior and cognition study (the lab was also observing another octopus, Abbott; both were named after the heptapod aliens in the movie “Arrival”). In total, the team found three more shorter instances that appeared similar. To Dr. Magnasco, the behaviors exhibited in Costello’s longest spell evoked the acting out of a dream. The curling of arms over his body looked like a defensive posture, he said. In the footage, the animal is seen perhaps trying to make himself look larger, and then he tries an evasive maneuver — inking. When he fails to escape, it seems like Costello seeks to subdue a threat by strangling the pipe, Dr. Magnasco said, adding, “This is the sequence of a fight.” © 2023 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28798 - Posted: 05.27.2023