Chapter 6. Evolution of the Brain and Behavior

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Links 1 - 20 of 1972

Jules Howard And so, the killer whale known as J35 is back to her old self. She is no longer carrying the dead body of a calf she held aloft in the water for more than two weeks. Her so-called tour of grief has ended, to the relief of a global audience who had become wrapped up in this heart-wrenching animal drama. Great news, right? Sure. Yet I have a strange feeling in my stomach. It’s a familiar one. The pedant in me is stirring, eager to get us to consider what we know about animals and what we don’t – and may never – know about their lives. It isn’t my aim to belittle J35 and her apparent pain, far from it. It’s rather to make sure we don’t accidentally dilute the emotions of a killer whale by making it all about us. First, I have form on this issue. A while ago, I published a book called Death on Earth and episodes of apparent animal grief was one of the areas upon which I focused. During my research, I drew up a list of all sorts of anecdotes about animals labelled (by respectable researchers) as evidence of “mourning” and “grief”. These included police dogs pawing at their master’s coffins, macaques resuscitating fallen loved ones and turtles appearing on beaches to mourn at makeshift graves made by humans for the turtles that didn’t make it. I was told by members of the public on Twitter about dogs going off food after losing kennel-mates and horses burying dead stablemates in hay and I was reminded regularly of those BBC documentaries featuring elephants in apparent (but I would argue edited) tears at the loss of a loved one. © 2018 Guardian News and Media Limited

Keyword: Emotions; Evolution
Link ID: 25343 - Posted: 08.17.2018

Yao-Hua Law What can males wear to look sexier? For zebra finches, the trick seemed simple: add a dash of red to their legs. Research conducted in the 1980s found that slipping red bands onto the legs of male birds turned them into sex magnets. Those studies became iconic in sexual selection research because they provided something rare in the discipline: strong, consistent effects. But data accumulated in recent years question these influential findings. Zebra finches (Taeniopygia guttata) are native Australian birds with a bright red-orange beak. They form monogamous breeding pairs in which the male and female cooperate to raise young. Easy to rear in captivity, zebra finches are model organisms for research in cognition and sexual selection. In the 1980s, ornithologist Nancy Burley, then at the University of Illinois, found that placing plastic leg bands of different colors—used by scientists to identify individual birds—on the legs of zebra finches affected the birds’ chances of mating. Burley reported, first in Science and then in other leading journals, that females preferred red-banded males and disliked green-banded males. Females also spent more time caring for nestlings sired by red-banded males. Burley’s results inspired subsequent research in female choice and maternal effects. But results contradictory to Burley’s began to emerge in the late 1990s. And this March, Wolfgang Forstmeier of the Max Planck Institute for Ornithology and colleagues published the strongest disagreement yet. Forstmeier’s lab ran eight experiments and analyzed unpublished data from four other labs and found no effects of leg-band colors on the reproductive success of male or female zebra finches. The new study also included a meta-analysis of 39 published studies, including 22 that supported leg-band color effects. The meta-analysis found that effect sizes shrank as sample sizes increased—a sign of selective reporting. © 1986 - 2018 The Scientist

Keyword: Sexual Behavior; Evolution
Link ID: 25333 - Posted: 08.15.2018

By Victoria Gill Science correspondent, BBC News Our primate cousins have surprised and impressed scientists in recent years, with revelations about monkeys' tool-using abilities and chimps' development of complex sign language. But researchers are still probing the question: why are we humans the only apes that can talk? That puzzle has now led to an insight into how different non-human primates' brains are "wired" for vocal ability. A new study has compared different primate species' brains. It revealed that primates with wider "vocal repertoires" had more of their brain dedicated to controlling their vocal apparatus. That suggests that our own speaking skills may have evolved as our brains gradually rewired to control that apparatus, rather than purely because we're smarter than non-human apes. Humans and other primates have very similar vocal anatomy - in terms of their tongues and larynx. That's the physical machinery in the throat which allows us to turn air into sound. So, as lead researcher Dr Jacob Dunn from Anglia Ruskin University in Cambridge explained, it remains a mystery that only human primates can actually talk. "That's likely due to differences in the brain," Dr Dunn told BBC News, "but there haven't been comparative studies across species." So how do our primate brains differ? That comparison is exactly what Dr Dunn and his colleague Prof Jeroen Smaers set out to do. They ranked 34 different primate species based on their vocal abilities - the number of distinct calls they are known to make in the wild. They then examined the brain of each species, using information from existing, preserved brains that had been kept for research. © 2018 BBC

Keyword: Language; Evolution
Link ID: 25314 - Posted: 08.10.2018

By Bilal Choudhry Killifish are a family of freshwater fish that have evolved to survive in the most difficult of situations. Here in the United States, for instance, the Atlantic killifish is known for having adapted to live in heavily polluted places like the Lower Passaic River. But in small murky puddles that come after heavy rains in parts of East Africa, another killifish, called Nothobranchius furzeri, or the African annual fish, has developed its own unique adaptations to its environment. Its embryos are able to enter a state of diapause, similar to hibernation in bears, when conditions aren’t right. It turns out that entering dormancy isn’t the only thing that’s unusual about this African killifish. In a paper published on Monday in Current Biology, a team of Czech researchers report that N. furzeri has the quickest known rate of sexual maturity of any vertebrate — approximately two weeks. By studying the fish’s unusual life cycle, they hope to gain insights into the process of aging in other vertebrates, including us. Dr. Martin Reichard, a biologist who is studying the evolution of aging at the Czech Academy of Sciences’ Institute of Vertebrate Biology, led a team of colleagues to Mozambique to study the fish’s developmental stages in the wild. There, they were able to observe embryos buried in the sand that had entered a dormant state. They also documented their maturation after rainfall. When N. furzeri receive cues from their environment, they can be flexible in sexual development. Under these circumstances, their embryos enter a stage of dormancy called embryonic diapause, a reproductive strategy that extends their gestational period and helps them survive unfavorable conditions, like a dry season. But when it rains, they undergo rapid growth, going from juvenile fish to mature adults that are able to reproduce in about two weeks. © 2018 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 25304 - Posted: 08.07.2018

By Susana Martinez-Conde The house cricket (Acheta domesticus) walked around the arena comfortably, certain of its surroundings. It looked about, perhaps hoping for food or mates, ignoring the scattered, browning, dead leaves. On previous visits to the arena, the cricket had been wary of the dead leaves, not knowing what to make of them. Then, after a prudent interval, it had ventured to feel them with its segmented antennae—tentatively at first, and later with growing confidence. Once the cricket determined the leaves were neither edible nor harmful, it quickly lost interest in them. Now it rarely bothered to explore the leaves, but took no great pains to avoid them either. The cricket’s conviction about the safety of the leaves was its fatal mistake: on this visit, one seemingly dead leaf lying on the arena was no such, but a masquerading ghost mantis (Phyllocrania paradoxa) waiting in ambush. Unaware of the concealed peril, the cricket drew ever closer to the predator. That’s when the mantis struck forth, grasping the cricket by one of its long jumping legs. As the cricket struggled against the mantis’ clutch, the predator started to feed. Dr John Skelhorn, Lecturer in Animal Cognition, has witnessed dozens of similar life-and-death encounters in his lab at Newcastle University’s Institute of Neuroscience. Skelhorn and his colleagues previously found that some animals masquerade as inanimate, inedible objects, to look less appealing to potential predators. Some examples include the orb web spider (Cyclosa ginnaga) and the larva of the giant swallowtail butterfly (Papilio cresphontes), both of which masquerade as bird droppings, and the larva of the feathered thorn moth (Selenia dentaria), which masquerades as a twig. © 2018 Scientific American

Keyword: Vision; Evolution
Link ID: 25299 - Posted: 08.06.2018

Tina Hesman Saey Humans’ gift of gab probably wasn’t the evolutionary boon that scientists once thought. There’s no evidence that FOXP2, sometimes called “the language gene,” gave humans such a big evolutionary advantage that it was quickly adopted across the species, what scientists call a selective sweep. That finding, reported online August 2 in Cell, follows years of debate about the role of FOXP2 in human evolution. In 2002, the gene became famous when researchers thought they had found evidence that a tweak in FOXP2 spread quickly to all humans — and only humans — about 200,000 years ago. That tweak swapped two amino acids in the human version of the gene for ones different than in other animals’ versions of the gene. FOXP2 is involved in vocal learning in songbirds, and people with mutations in the gene have speech and language problems. Many researchers initially thought that the amino acid swap was what enabled humans to speak. Speech would have given humans a leg up on competition from Neandertals and other ancient hominids. That view helped make FOXP2 a textbook example of selective sweeps. Some researchers even suggested that FOXP2 was the gene that defines humans, until it became clear that the gene did not allow humans to settle the world and replace other hominids, says archeaogeneticist Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, who was not involved in the study. “It was not the one gene to rule them all.” |© Society for Science & the Public 2000 - 2018

Keyword: Language; Genes & Behavior
Link ID: 25293 - Posted: 08.04.2018

Matthew Warren The evolution of human language was once thought to have hinged on changes to a single gene that were so beneficial that they raced through ancient human populations. But an analysis now suggests that this gene, FOXP2, did not undergo changes in Homo sapiens’ recent history after all — and that previous findings might simply have been false signals. “The situation’s a lot more complicated than the very clean story that has been making it into textbooks all this time,” says Elizabeth Atkinson, a population geneticist at the Broad Institute of Harvard and MIT in Cambridge, Massachusetts, and a co-author of the paper, which was published on 2 August in Cell1. Originally discovered in a family who had a history of profound speech and language disorders, FOXP2 was the first gene found to be involved in language production2. Later research touted its importance to the evolution of human language. A key 2002 paper found that humans carry two mutations to FOXP2 not found in any other primates3. When the researchers looked at genetic variation surrounding these mutations, they found the signature of a ‘selective sweep’ — in which a beneficial mutation quickly becomes common across a population. This change to FOXP2 seemed to have happened in the past 200,000 years, the team reported in Nature. The paper has been cited hundreds of times in the scientific literature. © 2018 Springer Nature Limited.

Keyword: Language; Genes & Behavior
Link ID: 25292 - Posted: 08.04.2018

By Carl Zimmer In 2003, researchers digging in a mountain cave on the Indonesian island of Flores discovered astonishing fossils of a tiny, humanlike individual with a small, chimp-sized brain. They called the species Homo floresiensis. These relatives of modern humans stood just over three feet tall. Several villages in the area, scientists noted, are inhabited by people whose average height is 4 feet 9 inches. Was this the result of interbreeding long ago between taller modern humans and shorter Homo floresiensis? Fifteen years after the bones’ discovery, a study of the DNA of living people on Flores has delivered a verdict. “It’s rare in science that you set about to answer a question and you get something of a definitive answer and it’s the end,” said Richard E. Green, a geneticist at the University of California, Santa Cruz, and a co-author of the study, published on Thursday in Science. “The answer is a clear enough ‘no’ that I’m done with it.” But as often happens in science, the answer to one question raises new ones. The study shows that at least twice in ancient history, humans and their relatives (known as hominins) arrived on Flores and then grew shorter. And not just humans: Other research has shown that elephants also arrived on Flores twice, and both times the species evolved into dwarves. So what mysterious power does this island have to shrink the body? When the fossils of Homo floresiensis first came to light, many researchers hoped they might still hold fragments of DNA. They were encouraged by the initial dating of the fossils — an estimated age of perhaps just 13,000 years. © 2018 The New York Times Company

Keyword: Evolution
Link ID: 25288 - Posted: 08.03.2018

Philip Lieberman In the 1960s, researchers at Yale University’s Haskins Laboratories attempted to produce a machine that would read printed text aloud to blind people. Alvin Liberman and his colleagues figured the solution was to isolate the “phonemes,” the ostensible beads-on-a-string equivalent to movable type that linguists thought existed in the acoustic speech signal. Linguists had assumed (and some still do) that phonemes were roughly equivalent to the letters of the alphabet and that they could be recombined to form different words. However, when the Haskins group snipped segments from tape recordings of words or sentences spoken by radio announcers or trained phoneticians, and tried to link them together to form new words, the researchers found that the results were incomprehensible.1 That’s because, as most speech scientists agree, there is no such thing as pure phonemes (though some linguists still cling to the idea). Discrete phonemes do not exist as such in the speech signal, and instead are always blended together in words. Even “stop consonants,” such as [b], [p], [t], and [g], don’t exist as isolated entities; it is impossible to utter a stop consonant without also producing a vowel before or after it. As such, the consonant [t] in the spoken word tea, for example, sounds quite different from that in the word to. To produce the vowel sound in to, the speakers’ lips are protruded and narrowed, while they are retracted and open for the vowel sound in tea, yielding different acoustic representations of the initial consonant. Moreover, when the Haskins researchers counted the number of putative phonemes that would be transmitted each second during normal conversations, the rate exceeded that which can be interpreted by the human auditory system—the synthesized phrases would have become an incomprehensible buzz. © 1986 - 2018 The Scientist.

Keyword: Language; Evolution
Link ID: 25176 - Posted: 07.06.2018

by Sarah Kaplan For years, scientists at the Smithsonian Tropical Research Institute in Panama had whispered about the remote island where monkeys used stone tools. A botanist had witnessed the phenomenon during a long-ago survey — but, being more interested in flora than fauna at the time, she couldn't linger to investigate. A return to the site would require new funds, good weather for a treacherous 35-mile boat ride, and days of swimming, hiking and camping amid rocky, wave-pounded shorelines and dense tropical forest. “For while, it kind of just stayed a rumor,” said Brendan Barrett, a behavioral ecologist at the Max Planck Institute in Germany and a visiting researcher at STRI. But when Barrett and his colleagues finally arrived at Jicarón Island in Panama's Coiba National Park last year, what they found was well-worth the effort: Tiny white-faced capuchin monkeys were using stones almost half their body weight as hammers to smash open shellfish, nuts and other foods. “We were stunned,” said Barrett, the lead author of a new paper on the discovery posted on the preprint website bioRxiv. The capuchins are the first animals of their genus observed using stone tools, and only the fourth group of nonhuman primates known to do so. Sophisticated, social, and tolerant of observation, they also provide scientists with an ideal system for studying what causes a species to venture into the stone age — and could help researchers understand how and why our own ancestors first picked up stone tools more than 2 million years ago. © 1996-2018 The Washington Post

Keyword: Evolution
Link ID: 25175 - Posted: 07.06.2018

By JoAnna Klein Owl eyes are round, but not spherical. These immobile, tubular structures sit on the front of an owl’s face like a pair of built-in binoculars. They allow the birds to focus in on prey and see in three dimensions, kind of like humans — except we don’t have to turn our whole heads to spot a slice of pizza beside us. Although owls and humans both have binocular vision, it has been unclear whether these birds of prey process information they collect from their environments like humans, because their brains aren’t as complex. But in a study published in the Journal of Neuroscience on Monday, scientists tested the ability of barn owls to find a moving target among various shifting backgrounds, a visual processing task earlier tested only in primates. The research suggests that barn owls, with far simpler brains than humans and other primates, also group together different elements as they move in the same direction, to make sense of the world around them. “Humans are not so different from birds as you may think,” said Yoram Gutfreund, a neuroscientist at Technion Israel Institute of Technology who led the study with colleagues from his university and RWTH Aachen University in Germany. A critical part of perception is being able to distinguish an object from its background. One way humans do this is by grouping elements of a scene together to perceive each part as a whole. In some cases, that means combining objects that move similarly, like birds flying in a flock, or the single bird that breaks away from it. Scientists have generally considered this type of visual processing as a higher level task that requires complex brain structures. As such, they’ve only studied it in humans and primates. But Dr. Gutfreund and his team believed this ability was more basic — like seeing past camouflage. A barn owl, for example, might have evolved a similar mechanism to detect a mouse moving in a meadow as wind blows the grass in the same direction. © 2018 The New York Times Company

Keyword: Vision; Evolution
Link ID: 25174 - Posted: 07.05.2018

By Elizabeth Pennisi Bats and their prey are in a constant arms race. Whereas the winged mammals home in on insects with frighteningly accurate sonar, some of their prey—such as the tiger moth—fight back with sonar clicks and even jamming signals. Now, in a series of bat-moth skirmishes (above), scientists have shown how other moths create an “acoustic illusion,” with long wing-tails that fool bats into striking the wrong place. The finding helps explain why some moths have such showy tails, and it may also provide inspiration for drones of the future. Moth tails vary from species to species: Some have big lobes at the bottom of the hindwing instead of a distinctive tail; others have just a short protrusion. Still others have long tails that are thin strands with twisted cuplike ends. In 2015, sensory ecologist Jesse Barber of Boise State University in Idaho and colleagues discovered that some silk moths use their tails to confuse bat predators. Now, graduate student Juliette Rubin has shown just what makes the tails such effective deterrents. Working with three species of silk moths—luna, African moon, and polyphemus—Rubin shortened or cut off some of their hindwings and glued longer or differently shaped tails to others. She then tied the moths to a string hanging from the top of a large cage and released a big brown bat (Eptesicus fuscus) inside. She used high-speed cameras and microphones to record the ensuing fight. © 2018 American Association for the Advancement of Science.

Keyword: Hearing; Evolution
Link ID: 25173 - Posted: 07.05.2018

By Karen Weintraub New Caledonian crows are known for their toolmaking, but Alex Taylor and his colleagues wanted to understand just how advanced they could be. Crows from New Caledonia, an island in the South Pacific, can break off pieces of a branch to form a hook, using it to pull a grub out of a log, for instance. Once, in captivity, when a New Caledonian male crow had taken all the available hooks, its mate Betty took a straight piece of wire and bent it to make one. “They are head and shoulders above almost every other avian subjects” at toolmaking, said Irene Pepperberg, an avian cognition expert and research associate in Harvard University’s department of psychology. “These crows are just amazing.” Dr. Taylor, a researcher at the University of Auckland in New Zealand, and several European colleagues wondered how the crows, without an ability to talk and showing no evidence of mimicry, might learn such sophisticated toolmaking. Perhaps, the scientists hypothesized in a new paper published Thursday in Scientific Reports, they used “mental template matching,” where they formed an image in their heads of tools they’d seen used by others and then copied it. “Could they look at a tool and just based on mental image of the tool — can they recreate that tool design?” Dr. Taylor said. “That’s what we set out to test, and that’s what our results show.” In a series of steps, the researchers taught the birds to feed pieces of paper into a mock vending machine to earn food rewards. The scientists chose a task that was similar enough to something the animals do in the wild — while also brand new. The birds had never seen card stock before, but learned how to rip it into big or little shapes after being shown they would get a reward for the appropriate size. The template used to show the birds the right size of paper was not available to them when they made their “tools,” yet the crows were able to use their beaks to tear off bits of paper, which they sometimes held between their feet for leverage. © 2018 The New York Times Company

Keyword: Intelligence; Evolution
Link ID: 25161 - Posted: 06.29.2018

By Elizabeth Gamillo Why does a wild rabbit flee when a person approaches it, but a domestic rabbit sticks around for a treat? A new study finds that domestication may have triggered changes in the brains of these—and perhaps other—animals that have helped them adapt to their new, human-dominated environment. The new study provides “specific and new insights” into the ongoing debate over the physiological factors shaping domestication and evolution, says Marcelo Sánchez-Villagra, a professor of paleobiology at the University of Zurich in Switzerland who was not involved with the work. The leader of the research team, animal geneticist Leif Andersson of Uppsala University in Sweden and Texas A&M University in College Station, thinks the process of domestication has led to changes in brain structure that allow the rabbit to be less nervous around humans. To find out, he and colleagues took MRI scans of the brains of eight wild and eight domestic rabbits and compared the results. The team found that the amygdala, a region of the brain that processes fear and anxiety, is 10% smaller in domesticated rabbits than in wild rabbits. Meanwhile, the medial prefrontal cortex, which controls responses to aggressive behavior and fear, is 11% larger in domesticated rabbits. The researchers also found that the brains of domesticated rabbits are less able to process information related to fight-or-flight responses because they have less white matter than their feral cousins do. White matter handles information processing. When a wild rabbit is in danger, more white matter is needed for faster reflexes and for learning what to be afraid of. © 2018 American Association for the Advancement of Science.

Keyword: Evolution; Emotions
Link ID: 25142 - Posted: 06.26.2018

Jennifer Ouellette Gerardo Ortiz remembers well the time in 2010 when he first heard his Indiana University colleague John Beggs talk about the hotly debated “critical brain” hypothesis, an attempt at a grand unified theory of how the brain works. Ortiz was intrigued by the notion that the brain might stay balanced at the “critical point” between two phases, like the freezing point where water turns into ice. A condensed matter physicist, Ortiz had studied critical phenomena in many different systems. He also had a brother with schizophrenia and a colleague who suffered from epilepsy, which gave him a personal interest in how the brain works, or doesn’t. Ortiz promptly identified one of the knottier problems with the hypothesis: It’s very difficult to maintain a perfect tipping point in a messy biological system like the brain. The puzzle compelled him to join forces with Beggs to investigate further. Ortiz’s criticism has beleaguered the theory ever since the late Danish physicist Per Bak proposed it in 1992. Bak suggested that the brain exhibits “self-organized criticality,” tuning to its critical point automatically. Its exquisitely ordered complexity and thinking ability arise spontaneously, he contended, from the disordered electrical activity of neurons. Bak’s canonical example of a self-organized critical system is a simple sandpile. If you drop individual grains of sand on top of a sandpile one by one, each grain has a chance of causing an avalanche. Bak and colleagues showed that those avalanches will follow a “power law,” with smaller avalanches occurring proportionally more frequently than larger ones. So if there are 100 small avalanches in which 10 grains slide down the side of the sandpile during a given period, there will be 10 larger avalanches involving 100 grains in the same period, and just one large avalanche involving 1,000 grains. When a huge avalanche collapses the whole pile, the base widens, and the sand begins to pile up again until it returns to its critical point, where, again, avalanches of any size may occur. The sandpile is incredibly complex, with millions or billions of tiny elements, yet it maintains an overall stability. All Rights Reserved © 2018

Keyword: Development of the Brain; Evolution
Link ID: 25137 - Posted: 06.25.2018

By Jon Cohen Until now, researchers wanting to understand the Neanderthal brain and how it differed from our own had to study a void. The best insights into the neurology of our mysterious, extinct relatives came from analyzing the shape and volume of the spaces inside their fossilized skulls. But a recent marriage of three hot fields—ancient DNA, the genome editor CRISPR, and "organoids" built from stem cells—offers a provocative, if very preliminary, new option. At least two research teams are engineering stem cells to include Neanderthal genes and growing them into "minibrains" that reflect the influence of that ancient DNA. None of this work has been published, but Alysson Muotri, a geneticist at the University of California, San Diego (UCSD) School of Medicine, described his group's Neanderthal organoids for the first time this month at a UCSD conference called Imagination and Human Evolution. His team has coaxed stem cells endowed with Neanderthal DNA into pea-size masses that mimic the cortex, the outer layer of real brains. Compared with cortical minibrains made with typical human cells, the Neanderthal organoids have a different shape and differences in their neuronal networks, including some that may have influenced the species's ability to socialize. "We're trying to recreate Neanderthal minds," Muotri says. Muotri focused on one of approximately 200 protein-coding genes that differ between Neanderthals and modern humans. Known as NOVA1, it plays a role in early brain development in modern humans and also is linked to autism and schizophrenia. Because it controls splicing of RNA from other genes, it likely helped produce more than 100 novel brain proteins in Neanderthals. Conveniently, just one DNA base pair differs between the Neanderthal gene and the modern human one. © 2018 American Association for the Advancement of Science.

Keyword: Development of the Brain; Evolution
Link ID: 25116 - Posted: 06.21.2018

By Virginia Morell When an adult striped dolphin emerged from the Mediterranean Sea in 2016 pushing, nudging, and circling the carcass of its dead female companion for more than an hour, a nearby boat of scientists fell silent. Afterward, the students aboard said they were certain the dolphin was grieving. But was this grief or some other response? In a new study, researchers are attempting to get to the bottom of a mystery that has plagued behavioral biologists for 50 years. Grief, in humans at least, is a reaction to the permanent severing of a strong social or family bond. Although chimpanzees, baboons, and elephants are thought to experience the complex emotion, scientists don’t yet know enough about it in other animals. There are dozens of photos and YouTube videos of grieflike behavior in dolphins: Some mothers have been seen carrying their dead infants in their mouths or on their backs for a week or longer, even as the body decomposes; a couple adult males have also been seen holding dead calves in their mouths. In the new study, cetacean biologist Giovanni Bearzi of Dolphin Biology and Conservation in Pordenone, Italy, and his colleagues at other institutions analyzed 78 scientific reports from 1970 to 2016 of these kinds of displays—which they labeled “postmortem-attentive behavior.” They found that just 20 of 88 cetacean (dolphin and whale) species engage in them. Of those, most were dolphins from the Sousa and Tursiops genera. Just one was a baleen whale—a humpback. © 2018 American Association for the Advancement of Science.

Keyword: Emotions; Evolution
Link ID: 25110 - Posted: 06.20.2018

By Natalie Angier In advance of Father’s Day, let’s take a moment to sort out the differences and similarities between “Dad jeans” and “Dad genes.” Dad jeans are articles of sex-specific leisure clothing, long mocked for being comfy, dumpy and elastic-waisted but lately reinvented as a fashion trend, suitable for male bodies of all shapes and ages. Dad genes are particles on the sex-specific Y chromosome, long mocked for being a stunted clump of mostly useless nucleic waste but lately revealed as man’s fastest friend, essential to the health of male bodies and brains no matter the age. Yes, dear fathers and others born with the appurtenances generally designated male. We live in exciting times, and that includes novel insights into the sole chromosomal distinction between you and the women now prowling the aisles at the hardware store. (“Didn’t he say he could use a new bow saw? Or some halogen light bulbs?”) Researchers have discovered that, contrary to longstanding assumptions, the Y chromosome is not limited to a handful of masculine tasks, like specifying male body parts in a developing embryo or replenishing the sperm supply in an adult man. New evidence indicates that the Y chromosome participates in an array of essential, general-interest tasks in men, like stanching cancerous growth, keeping arteries clear and blocking the buildup of amyloid plaque in the brain. As a sizable percentage of men age, their blood and other body cells begin to spontaneously jettison copies of the Y chromosome, sometimes quickly, sometimes slowly. That unfortunate act of chromosomal decluttering appears to put the men at a heightened risk of Alzheimer’s disease, leukemia and other disorders. “I’m quite certain,” said Lars Forsberg, an associate professor of medical genetics at Uppsala University in Sweden, “that the loss of the Y chromosome with age explains a very large proportion of the increased mortality in men, compared to women.” Other researchers are tracing the evolution of the Y chromosome and comparing the version found in modern men with those of our close relatives, both living and extinct. © 2018 The New York Times Company

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 25075 - Posted: 06.11.2018

Susan Milius A little brain can be surprisingly good at nothing. Honeybees are the first invertebrates to pass a test of recognizing where zero goes in numerical order, a new study finds. Even small children struggle with recognizing “nothing” as being less than one, says cognitive behavioral scientist Scarlett Howard of the Royal Melbourne Institute of Technology in Australia. But honeybees trained to fly to images of greater or fewer dots or whazzits tended to rank a blank image as less than one, Howard and colleagues report in the June 8 Science. Despite decades of discoveries, nonhuman animals still don’t get due credit outside specialist circles for intelligence, laments Lars Chittka of Queen Mary University of London, who has explored various mental capacities of bees. For the world at large, he emphasizes that the abilities described in the new paper are “remarkable.” Researchers recognize several levels of complexity in grasping zero. Most animals, or maybe all, can understand the simplest level — just recognizing that the absence of something differs from its presence, Howard says. Grasping the notion that absence could fit into a sequence of quantities, though, seems harder. Previously, only some primates such as chimps and vervet monkeys, plus an African gray parrot named Alex, have demonstrated this level of understanding of the concept of zero (SN: 12/10/16, p. 22). |© Society for Science & the Public 2000 - 2018

Keyword: Intelligence; Evolution
Link ID: 25069 - Posted: 06.08.2018

By Maggie Koerth-Baker If an animal is smart enough, should we treat it like a human? An abstract question, but one that found its way into a courtroom recently. A case bidding for consideration by the New York State Court of Appeals sought to extend the legal concept of habeas corpus — which allows a person to petition a court for freedom from unlawful imprisonment — to cover two privately-owned chimpanzees. The case for giving the chimps a human right like freedom from unlawful incarceration is based on their similarity to humans — they can think, feel and plan, argue the people bringing the case on behalf of the chimpanzees, so shouldn’t they have some guarantees of liberty? The court declined to hear the case, but one judge did say that some highly intelligent animals probably should be treated more like people and less like property. It’s just one judge, but you hear this kind of thing a lot from animal rights activists. The Nonhuman Rights Project, the nonprofit behind the habeas corpus lawsuit, has a stated goal of securing increased, human-like rights for great apes, elephants, dolphins and whales — highly intelligent, charismatic mammals. So, does a chimpanzee deserve more rights than, say, a pigeon? The logic that leads to “yes” is clear enough, but putting it into practice would be tough, scientists say. Because when it comes to measuring intelligence, we’re actually a little dumb. One of the problems: Animals don’t stack up the way you’d expect. “[Pigeons have] knocked our socks off in our own lab and other people’s labs in terms of what they can do,” said Edward Wasserman, a professor of experimental psychology at the University of Iowa. “Pigeons can blow the doors off monkeys in some tasks.” Experts who study animal intelligence across species say we can’t rank animals by their smarts — scientists don’t even try anymore — which means there’s no objective way to determine which animals would deserve more human-like rights.

Keyword: Evolution; Animal Rights
Link ID: 25047 - Posted: 06.01.2018