Chapter 12. Sex: Evolutionary, Hormonal, and Neural Bases

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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 Laura Sanders Pregnancy overhauls a woman’s body. The brain is no exception. A detailed study of a woman’s brain before, during and after pregnancy revealed sweeping neural changes, some of which stuck around months after her baby was born. The dataset, published September 16 in Nature Neuroscience, is the first comprehensive view of the neural changes that accompany gestation — a sort of “what to expect when you’re expecting” for the brain. “The results of this case study are astonishing,” says neuroscientist Clare McCormack of New York University Langone Health. “Here we see, for the first time in humans, the extent of brain changes that are under way throughout pregnancy.” This research joins a small number of other studies aimed at understanding the female brain at various stages of life (SN: 9/29/22). Collectively, the work suggests that the process of becoming a mother, called matrescence, is another stage of development, like the brain overhaul that happens in adolescence (SN: 2/27/23). Earlier experiments mostly compared brains of women before and after their pregnancies and inferred what happens in between (SN: 12/19/16). “There was a missing piece,” McCormack says. “The nine months of pregnancy was a black box, and we could only guess what that trajectory looks like.” With four MRI scans before pregnancy, 15 scans during pregnancy and seven scans in the two years after the baby was born, the new study follows the entire arc for one mother. © Society for Science & the Public 2000–2024.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29485 - Posted: 09.18.2024

By Ellen Barry A study of adolescent brain development that tested children before and after coronavirus pandemic lockdowns in the United States found that girls’ brains aged far faster than expected, something the researchers attributed to social isolation. The study from the University of Washington, published on Monday in the Proceedings of the National Academy of Sciences, measured cortical thinning, a process that starts in either late childhood or early adolescence, as the brain begins to prune redundant synapses and shrink its outer layer. Thinning of the cortex is not necessarily bad; some scientists frame the process as the brain rewiring itself as it matures, increasing its efficiency. But the process is known to accelerate in stressful conditions, and accelerated thinning is correlated with depression and anxiety. Scans taken in 2021, after shutdowns started to lift, showed that both boys and girls had experienced rapid cortical thinning during that period. But the effect was far more notable in girls, whose thinning had accelerated, on average, by 4.2 years ahead of what was expected; the thinning in boys’ brains had accelerated 1.4 years ahead of what was expected. “That is a stunning difference,” said Patricia K. Kuhl, a director of the Institute for Learning and Brain Sciences at the University of Washington and one of the study’s authors. The results, she added, suggested that “a girl who came in at 11, and then returned to the lab at age 14, now has a brain that looks like an 18-year-old’s.” Dr. Kuhl attributed the change to “social deprivation caused by the pandemic,” which she suggested had hit adolescent girls harder because they are more dependent on social interaction — in particular, talking through problems with friends — as a way to release stress. The difference between the genders “is just as clear as night and day,” Dr. Kuhl said. “In the girls, the effects were all over the brain — all the lobes, both hemispheres.” © 2024 The New York Times Company

Keyword: Stress; Development of the Brain
Link ID: 29477 - Posted: 09.11.2024

By Frieda Klotz For five years, Clare Dolman took lithium to manage her bipolar disorder. The medicine kept her happy and well with few side effects, and she described it as a wonder drug. But when she began to plan for a pregnancy, her psychiatrist advised her to go off the medication to protect the fetus. This was 1988, and it was the standard guidance at the time. While Dolman experienced some stresses during the pregnancy, her mood remained stable. But soon after giving birth, she began to experience mild hallucinations. “I thought, yes, there’s something wrong here,” she recalled. “But I had the insight still to see that I was getting ill, and my husband knew I was getting ill because he had seen me really bad.” She went on to spend five weeks in the hospital. Clare Dolman at the launch of the Bipolar Commission at the U.K. Parliament. Dolman, who has bipolar disorder, stopped taking lithium during her own pregnancies more than 30 years ago. She later became a mental health advocate and has studied the experiences of pregnant women with the illness. Visual: Courtesy of Clare Dolman Bipolar disorder involves extreme fluctuations in mood and is classified into different types according to symptoms and severity. For women with the condition, pregnancy can be a fraught endeavor as they balance the health of their growing fetus with their own mental state. Many, like Dolman, stop taking the medications that keep them well — which can lead to a recurrence of symptoms — and some avoid pregnancy altogether.

Keyword: Schizophrenia; Sexual Behavior
Link ID: 29475 - Posted: 09.11.2024

By Darren Incorvaia Imagine being a male firefly when suddenly the telltale flashing of a female catches your eye. Enthralled, you speed toward love’s embrace — only to fly headfirst into a spider’s web. That flashy female was in fact another male firefly, himself trapped in the web, and the spider may have manipulated his light beacon to lure you in. This high-stakes drama plays out nightly in the Jiangxia District of Wuhan, China. There, researchers have found that male fireflies caught in the webs of the orb-weaver spider Araneus ventricosus flash their light signals more like females do, which leads other males to get snagged in the same web. And weirdly, the spiders might be making them do this, almost like hunters blowing a duck call to attract prey. “The idea that a spider can manipulate the signaling of a prey species is very intriguing,” said Dinesh Rao, a spider biologist at the University of Veracruz in Mexico. “They show clearly that a trapped firefly in the web attracts more fireflies.” Dr. Rao was not involved in the research, but served as a peer reviewer of the paper published Monday in the journal Current Biology. Xinhua Fu, a zoologist at Huazhong Agricultural University in Wuhan, was in the field surveying firefly diversity when he first noticed that male fireflies seemed to end up ensnared in orb-weaver spider webs more often than females. Wondering if the spiders were somehow specifically attracting males, he teamed up with Daiqin Li and Shichang Zhang, animal behavior experts from nearby Hubei University, to get to the bottom of this sticky mystery. Working near paddy fields and ponds, the researchers observed the flashing of trapped male fireflies and saw that it more closely resembled that of females than of free-flying males. Trapped males flashed using only one of their two bioluminescent lantern organs, and they made one flash at a time rather than multiple flashes in quick succession, the same lighting signals females send when trying to attract males. © 2024 The New York Times Company

Keyword: Animal Communication; Sexual Behavior
Link ID: 29443 - Posted: 08.21.2024

By Liam Drew In November 2008, neuroscientist Susana Carmona — then a postdoc studying attention deficit hyperactivity disorder — was driving two colleagues to a party when one of them revealed that she was thinking about having a child. The trio became so engulfed in conversation about how pregnancy might change her brain that they diverted from the party and headed to their laboratory to search the literature. They found numerous studies in rodents, but in humans, “there was basically nothing at all”, says Carmona. Shocked by this gap in research, Carmona and her colleagues convinced their mentor at the Autonomous University of Barcelona, Spain, Oscar Vilarroya, to let them run a study using magnetic resonance imaging (MRI) to measure the neuroanatomy of women before they became pregnant, and then again after they gave birth. Squeezed in alongside their main projects, the investigation took eight years and included dozens of participants. The results, published in 2016, were revelatory1. Two to three months after giving birth, multiple regions of the cerebral cortex were, on average, 2% smaller than before conception. And most of them remained smaller two years later. Although shrinkage might evoke the idea of a deficit, the team showed that the degree of cortical reduction predicted the strength of a mother’s attachment to her infant, and proposed that pregnancy prepares the brain for parenthood. Today, Carmona, now at the Gregorio Marañón Health Research Institute in Madrid, is one of several scientists uncovering how pregnancy and parenthood transform the brain. Elseline Hoekzema, one of Carmona’s passengers that evening in 2008, is another. In 2022, Hoekzema, who is now at the Amsterdam University Medical Centre in the Netherlands, confirmed that the cortical regions that shrink during pregnancy also function differently for at least a year after giving birth2. These studies and others, say researchers, highlight a transformational life event that has long been neglected by neuroscience — one that around 140 million women experience annually.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29418 - Posted: 08.02.2024

By Miryam Naddaf Researchers have identified neurons in the brains of baby mice that enable them to form a unique, strong bond with their mother in the first few days of life. Stimulating these neurons in mouse pups that had been separated from their mother could mimic the soothing effect of their mother’s presence, and reduced behaviours associated with stress. The findings, published today in Science1, offer fresh clues about the formation of the mother–infant bond in mammals, and could help researchers to better understand how brain development influences behaviour. “We know very little about how the brains of infants make sense of their social world,” says study co-author Marcelo Dietrich, a neurobiologist at Yale University in New Haven, Connecticut. “When I started my lab ten years ago, and I wanted to study this kind of stuff, people said it was delusional. It will fail. It’s too difficult.” Now, “we show that it’s possible: one can do rigorous science and try to understand these mechanisms that are potentially very important for development and health”. “I see these neurons as the ‘I feel good with mommy’ neurons,” says Catharine Dulac, a neuroscientist at the University of Harvard in Cambridge, Massachusetts. “The features that [they] discovered provide some framework to think about humans.” Bonding in the brain Dietrich and his team studied nursing mouse pups that were between 16 and 18 days old. They used live imaging techniques to record activity in the zona incerta (ZI), a thin layer of grey matter located below the thalamus, while the animals interacted with their mother. © 2024 Springer Nature Limited

Keyword: Sexual Behavior
Link ID: 29409 - Posted: 07.27.2024

By Phie Jacobs Is there really such a thing as a “male” or “female” brain? Sex certainly seems to affect a person’s risk of developing various psychiatric and other brain-related conditions—but scientists aren’t entirely sure why. Attention-deficit/hyperactivity disorder for example, is more commonly diagnosed in individuals who were assigned male at birth (AMAB), whereas those assigned female at birth (AFAB) are more likely to exhibit symptoms of anxiety. It’s unclear, however, whether these differences are actually driven by sex, or have more to do with how people are perceived and treated based on their sex or gender. Now, new research suggests sex and gender are associated with distinct brain networks. Published today in Science Advances, the findings draw on brain imaging data from nearly 5000 children to reveal that gender and sex aren’t just distinct from one another in society—they also play unique roles in biology. In science, the term “biological sex” encompasses a variety of genetic, hormonal, and anatomical characteristics. People are typically assigned “male” or “female” as their sex at birth, although the medical establishment in recent years has begun to acknowledge that sex doesn’t always fall neatly into binary categories. Indeed, about 0.05% of children born in the United States are assigned intersex at birth. Gender, by contrast, has more to do with a person’s attitudes, feelings, and behavior—and may not always align with the sex they were assigned at birth. These nuances often go unrecognized in neuroscience, says Sheila Shanmugan, a reproductive psychiatrist at the University of Pennsylvania who wasn’t involved in the new study. Sex and gender-based differences in the brain “have historically been understudied,” she explains, “and terms describing each are often conflated.” © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Brain imaging
Link ID: 29393 - Posted: 07.13.2024

By Claire Yuan Men and women experience pain differently, and until now, scientists didn’t know why. New research says it may be in part due to differences in male and female nerve cells. Pain-sensing nerve cells from male and female animal tissues responded differently to the same sensitizing substances, researchers report June 3 in Brain. The results suggest that at the cellular level, pain is produced differently between the sexes. The results might allow researchers “to come up with drugs that would be specific to treat female patients or male patients,” says Katherine Martucci, a neuroscientist who studies chronic pain at Duke University School of Medicine and was not involved in the study. “There’s no debate about it. They’re seeing these differences in the cells.” Some types of chronic and acute pain appear more often in one sex, but it’s unclear why. For instance, about 50 million adults in the United States suffer from chronic pain conditions, many of which are more common in women (SN: 5/22/23). Similar disparities exist for acute conditions. Such differences prompted pain researcher Frank Porreca of the University of Arizona Health Sciences in Tucson and colleagues to study nerve cells called nociceptors, which can act like alarm sensors for the body. The cells’ pain sensors, found in skin, organs and elsewhere in the body, can detect potentially dangerous stimuli and send signals to the brain, which then interprets the information as pain. In some cases, the nerve cells can become more sensitive to outside stimulation, registering even gentle sensations — like a shirt rubbing sunburned skin — as pain. © Society for Science & the Public 2000–2024.

Keyword: Pain & Touch; Sexual Behavior
Link ID: 29366 - Posted: 06.24.2024

By Sara Reardon Specific nerve cells on the penis and clitoris detect vibrations and then become activated, causing sexual behaviours such as erections, a study in mice has revealed1. The findings could lead to new treatments for conditions such as erectile dysfunction, or for restoring sexual function in people with lower-body paralysis. Krause corpuscles — nerve endings in tightly wrapped balls located just under the skin — were first discovered in human genitals more than 150 years ago. The structures are similar to touch-activated corpuscles found on people’s fingers and hands, which respond to vibrations as the skin moves across a textured surface. But there is little research into how the genital corpuscles work and how they are involved in sex, probably because the topic is sometimes considered taboo. “It’s been hard to get people to work on this because some people have a hard time talking about it,” says David Ginty, a sensory neurobiologist at Harvard Medical School in Boston, Massachusetts, who led the team that conducted the latest research. “But I don’t, because the biology is so interesting.” Ginty and other sensory biologists have long wanted to study these mysterious neuron balls. But activating and tracking specific neurons was nearly impossible until advanced molecular techniques emerged in the past 20 years. In a 19 June paper in Nature1, Ginty and his collaborators activated the Krause corpuscles in both male and female mice using various mechanical and electrical stimuli. The neurons fired in response to low-frequency vibrations in the range of 40–80 hertz. Ginty notes that these frequencies are generally used in many sex toys; humans, it seems, realized that this was the best way to stimulate Krause corpuscles before any official experiments were published. © 2024 Springer Nature Limited

Keyword: Sexual Behavior; Pain & Touch
Link ID: 29365 - Posted: 06.24.2024

By Virginia Morell Leaping over waves or body surfing side by side, dolphins are a fun-loving bunch. But their frolicking—and that of species from hyenas to humans—has long baffled evolutionary biologists. Why expend so much energy on play? A new study offers an intriguing explanation: Juvenile male dolphins use play to acquire the skills required for fathering calves, researchers report today in the Proceedings of the National Academy of Sciences. Most significantly, the scientists found the most playful males go on to have more calves as adults. The study is likely to spur further research into play behavior in additional species, other scientists say. “It’s exciting research, and it solves an evolutionary puzzle,” says Jennifer Smith, a behavioral ecologist at the University of Wisconsin–Eau Claire. “This is the first study to link play behavior in the wild to reproductive success.” Since 1982, scientists have observed some 200 male Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the exceptionally clear waters of Shark Bay in Australia. About 20 years ago, the researchers noticed that young males, 4 to 12 years old, often played together as if they were herding a fertile female, flanking her on either side, while swimming in sync with each other and making popping vocalizations. This kind of “synchronicity is crucial for male reproduction,” says Kathryn Holmes, a behavioral biologist with the Shark Bay Dolphin Research project and lead author of the new study. The young dolphins’ behaviors were strikingly similar to those of the adults. “We wondered if this was ‘play practice’ for the adult behaviors,” Holmes says. So she and her colleagues closely tracked 28 juvenile males for 4 to 5 months over several years, recording their interactions and play behaviors. When socializing, the males “played almost continuously,” Holmes says. “They seemed to never tire of their games.” © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 29353 - Posted: 06.11.2024

By Amorina Kingdon Like most humans, I assumed that sound didn’t work well in water. After all, Jacques Cousteau himself called the ocean the “silent world.” I thought, beyond whales, aquatic animals must not use sound much. How wonderfully wrong I was. In water a sound wave travels four and a half times faster, and loses less energy, than in air. It moves farther and faster and carries information better. In the ocean, water exists in layers and swirling masses of slightly different densities, depending on depth, temperature, and saltiness. The physics-astute reader will know that the density of the medium in which sound travels influences its speed. So, as sound waves spread through the sea, their speed changes, causing complex reflection or refraction and bending of the sound waves into “ducts” and “channels.” Under the right circumstances, these ducts and channels can carry sound waves hundreds and even thousands of kilometers. What about other sensory phenomena? Touch and taste work about the same in water as in air. But the chemicals that tend to carry scent move slower in water than in air. And water absorbs light very easily, greatly diminishing visibility. Even away from murky coastal waters, in the clearest seas, light vanishes below several hundred meters and visibility below several dozen. So sound is often the best, if not only, way for ocean and freshwater creatures to signal friends, detect enemies, and monitor the world underwater. And there is much to monitor: Earthquakes, mudslides, and volcanic activity rumble through the oceans, beyond a human’s hearing range. Ice cracks, booms, and scrapes the seafloor. Waves hiss and roar. Raindrops plink. If you listen carefully, you can tell wind speed, rainfall, even drop size, by listening to the ocean as a storm passes. Even snowfall makes a sound. © 2024 NautilusNext Inc.,

Keyword: Animal Communication; Sexual Behavior
Link ID: 29341 - Posted: 06.04.2024

By Sumeet Kulkarni As spring turns to summer in the United States, warming conditions have started to summon enormous numbers of red-eyed periodical cicadas out of their holes in the soil across the east of the country. This year sees an exceptionally rare joint emergence of two cicada broods: one that surfaces every 13 years and another with a 17-year cycle. They last emerged together in 1803, when Thomas Jefferson was US president. This year, billions or even trillions of cicadas from these two broods — each including multiple species of the genus Magicicada — are expected to swarm forests, fields and urban neighbourhoods. To answer readers’ cicada questions, Nature sought help from three researchers. Katie Dana is an entomologist affiliated with the Illinois Natural History Survey at the University of Illinois at Urbana-Champaign. John Lill is an insect ecologist at George Washington University in Washington DC. Fatima Husain is a cognitive neuroscientist at the University of Illinois at Urbana-Champaign. Their answers have been edited for length and clarity. Why do periodical cicadas have red eyes? JL: We’re not really sure. We do know that cicadas’ eyes turn red in the winter before the insects come out. The whole coloration pattern in periodical cicadas is very bright: red eyes, black and orange wings. They’re quite different from the annual cicadas, which are green and black, and more camouflaged. It’s a bit of an enigma why the periodical ones are so brightly coloured, given that it just makes them more obvious to predators. There are no associated defences with being brightly coloured — it kind of flies in the face of what we know about bright coloration in a lot of other animals, where usually it’s some kind of signal for toxicity. There also exist mutants with brown, orange, golden or even blue eyes. People hunt for blue-eyed ones; it’s like trying to find a four-leaf clover. © 2024 Springer Nature Limited

Keyword: Animal Communication; Sexual Behavior
Link ID: 29339 - Posted: 06.04.2024

Sacha Pfeiffer A few weeks ago, at about 6:45 in the morning, I was at home, waiting to talk live on the air with Morning Edition host Michel Martin about a story I'd done, when I suddenly heard a loud metallic hammering. It sounded like a machine was vibrating my house. It happened again about 15 seconds later. And again after that. This rhythmic clatter seemed to be coming from my basement utility closet. Was my furnace breaking? Or my water heater? I worried that it might happen while I was on the air. Luckily, the noise stopped while I spoke with Michel, but restarted later. This time I heard another sound, a warbling or trilling, possibly inside my chimney. Was there an animal in there? I ran outside, looked up at my roof — and saw a woodpecker drilling away at my metal chimney cap. I've seen and heard plenty of woodpeckers hammer on trees. But never on metal. So to find out why the bird was doing this, I called an expert: Kevin McGowan, an ornithologist at the Cornell Lab of Ornithology who recently created a course called "The Wonderful World of Woodpeckers." McGowan said woodpeckers batter wood to find food, make a home, mark territory and attract a mate. But when they bash away at metal, "what the birds are trying to do is make as big a noise as possible," he said, "and a number of these guys have found that — you know what? If you hammer on metal, it's really loud!" Woodpeckers primarily do this during the springtime breeding season, and their metallic racket has two purposes, "basically summarized as: All other guys stay away, all the girls come to me," McGowan said. "And the bigger the noise, the better." © 2024 npr

Keyword: Sexual Behavior; Animal Communication
Link ID: 29333 - Posted: 06.02.2024

By Clay Risen Academic conferences are usually staid affairs, but the 1973 International Symposium on Gender Identity, held in Dubrovnik, Yugoslavia, was an exception. Everything was peaceful until a psychologist named John Money stood and yelled, “Mickey Diamond, I hate your guts!” Milton Diamond, a sexologist who had gone by Mickey since childhood, was sitting on the other side of the room. Dr. Money and Dr. Diamond were bitter rivals: Dr. Money, a nationally recognized researcher at Johns Hopkins University, had long argued that sexual and gender identity are neutral at birth and shaped primarily by an infant’s surroundings. Dr. Diamond, who was just beginning his career at the University of Hawaii, strongly disagreed, and had said so repeatedly — including in a widely read 1965 critique of Dr. Money’s work. He took particular issue with Dr. Money’s recommendation that intersex infants have surgery to “correct” their genitals. Dr. Money rushed over to Dr. Diamond, getting in his face, furiously insisting he was right. Dr. Diamond only replied, “The data is not there.” At one point, eyewitnesses reported that Dr. Money slugged Dr. Diamond, though Dr. Diamond later said he didn’t remember it. The incident, reported by the journalist John Colapinto in Rolling Stone magazine and in a subsequent book, “As Nature Made Him: The Boy Who Was Raised as a Girl” (2000), was especially heated because of a recent announcement by Dr. Money. He had been working with a child who in 1965, after his penis was irreparably damaged during a circumcision, had undergone further surgery to remove his male genitalia. The child was then raised as a girl, taking on all the conventional physical and emotional characteristics of a female adolescent — happily, Dr. Money said. Though the child was not born intersex, Dr. Money claimed that the case proved that gender and sexual identity were malleable and that intersex children should indeed receive surgery. © 2024 The New York Times Company

Keyword: Sexual Behavior
Link ID: 29297 - Posted: 05.09.2024

By Gillian Dohrn “Puppy-dog eyes didn’t just evolve for us, in domestic dogs,” says comparative anatomist Heather Smith. Her team’s work has thrown a 2019 finding1 that the muscles in dogs’ eyebrows evolved to communicate with humans in the doghouse by showing that African wild dogs also have the muscles to make the infamous pleading expression. The study was published on 10 April in The Anatomical Record2. Now, one of the researchers who described the evolution of puppy-dog eyebrow muscles is considering what the African dog discovery means for canine evolution. “It opens a door to thinking about where dogs come from, and what they are,” says Anne Burrows, a biological anthropologist at the Duquesne University in Pittsburgh, Pennsylvania, and author of the earlier paper. The 2019 study garnered headlines around the world when it found that the two muscles responsible for creating the sad–sweet puppy-dog stare are pronounced in several domestic breeds (Canis familiaris), but almost absent in wolves (Canis lupus). If the social dynamic between humans and dogs drove eyebrow evolution, Smith wondered whether the highly social African wild dog might also have expressive brows. African wild dogs (Lycaon pictus) are native to sub-Saharan Africa. Between 1997 and 2012, their numbers dropped by half in some areas. With only 8,000 or so remaining in the wild, studying them is difficult but crucial for conservation efforts. Smith, who is based at Midwestern University in Glendale, Arizona, and her colleagues dissected a recently deceased African wild dog from Phoenix Zoo. They found that both the levator anguli oculi medalis (LAOM) and the retractor anguli oculi lateralis (RAOL) muscles, credited with creating the puppy-dog expression, were similar in size to those of domestic dog breeds.

Keyword: Emotions; Sexual Behavior
Link ID: 29295 - Posted: 05.07.2024

By Elizabeth Anne Brown The beluga whale wears its heart on its sleeve — or rather, its forehead. Researchers have created a visual encyclopedia of the different expressions that belugas (Delphinapterus leucas) in captivity seem to make with their highly mobile “melon,” a squishy deposit of fat on the forehead that helps direct sound waves for echolocation. Using muscles and connective tissue, belugas can extend the melon forward until it juts over their lips like the bill of a cap; mush it down until it’s flattened against their skull; lift it vertically to create an impressive fleshy top hat; and shake it with such force that it jiggles like Jell-O. “If that doesn’t scream ‘pay attention to me,’ I don’t know what does,” says animal behaviorist Justin Richard of the University of Rhode Island in Kingston. “It’s like watching a peacock spread their feathers.” Before Richard became a scientist, he spent a decade as a beluga trainer at the Mystic Aquarium in Connecticut, working closely with the enigmatic animals. “Even as a trainer, I knew the shapes meant something,” Richard says. “But nobody had been able to put together enough observations to make sense of it.” Over the course of a year, from 2014 to 2015, Richard and colleagues recorded interactions between four belugas at the Mystic Aquarium. Analyzing the footage revealed that the belugas make five distinct melon shapes the scientists dubbed flat, lift, press, push and shake. The belugas sported an average of nearly two shapes per minute during social interaction, the team reports March 2 in Animal Cognition. © Society for Science & the Public 2000–2024

Keyword: Animal Communication; Evolution
Link ID: 29291 - Posted: 05.03.2024

By Michael S. Rosenwald Prairie voles are stocky rodents and Olympian tunnellers that surface in grassy areas to feast on grass, roots and seeds with their chisel-shaped teeth, sprouting migraines in farmers and gardeners. But to Larry Young, they were the secret to understanding romance and love. Professor Young, a neuroscientist at Emory University in Atlanta, used prairie voles in a series of experiments that revealed the chemical process for the pirouette of heart-fluttering emotions that poets have tried to put into words for centuries. He died on March 21 in Tsukuba, Japan, where he was helping to organize a scientific conference. He was 56. The cause was a heart attack, his wife, Anne Murphy, said. With their beady eyes, thick tails and sharp claws, prairie voles are not exactly cuddly. But among rodents, they are uniquely domestic: They are monogamous, and the males and females form a family unit to raise their offspring together. “Prairie voles, if you take away their partner, they show behavior similar to depression,” Professor Young told The Atlanta-Journal Constitution in 2009. “It’s almost as if there’s withdrawal from their partner.” That made them ideal for laboratory studies examining the chemistry of love. In a study published in 1999, Professor Young and his colleagues exploited the gene in prairie voles associated with the signaling of vasopressin, a hormone that modulates social behavior. They boosted vasopressin signaling in mice, which are highly promiscuous. Headline writers were amused. “Gene Swap Turns Lecherous Mice Into Devoted Mates,” The Ottawa Citizen declared. The Fort Worth Star-Telegram: “Genetic Science Makes Mice More Romantic.” The Independent in London: “‘Perfect Husband’ Gene Discovered.” © 2024 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29288 - Posted: 05.03.2024

By Joshua Cohen In the U.S., 23 states have passed legislation to ban medicalized care for minors with gender dysphoria, or the experience of distress that can occur when a person’s gender identity does not match the sex they were assigned at birth. On the other hand, 12 state legislatures have introduced laws to protect access to youth transgender care. Such care can include puberty blockers, which are medications that suppress the body’s production of sex hormones, and cross-sex hormones like testosterone or estrogen that alter secondary sex characteristics. It also may include sexual reassignment surgery in rare instances. U.S. policies on both ends of the spectrum are not science-driven but rather emanate from polar-opposite ideologies. Unlike in Europe, there doesn’t appear to be room for a non-ideological process for determining what the best care is that weighs the emerging clinical evidence and adjusts policies accordingly. As reported in Axios, state efforts to restrict various forms of transgender medicine are being fueled by religious groups that aim to shape policy based on their strongly held beliefs around the immutability of gender and family. Faith-based objections to transgender care come from a worldview in which God created humans as male or female. Here, the role of parents’ rights features prominently, as well as a conviction that adolescents are insufficiently mature to decide on trans alterations to their bodies. Moreover, lawmakers point out that some young people later regret having had irreversible body-altering treatment. The bans on care can be driven by extreme religious views. In one example, The Associated Press reported last year that Oklahoma state Sen. David Bullard introduced what he called the “Millstone Act” — a bill that would make the act of providing gender transition procedures to anyone under the age of 26 a felony — by citing a Bible passage that suggests those who cause children to sin should be drowned. The age limit was later lowered to 18.

Keyword: Sexual Behavior
Link ID: 29287 - Posted: 05.03.2024

In 2023, students protested against a new policy in Texas, where parents would be notified if their child asks to be identified as transgender.Credit: Brett Coomer/Houston Chronicle/Getty This week, Nature is launching a collection of opinion articles on sex and gender in research. Further articles will be published in the coming months. The series will highlight the necessity and challenges of studying a topic that is both hugely under-researched and, increasingly, the focus of arguments worldwide — many of which are neither healthy nor constructive. Some scientists have been warned off studying sex differences by colleagues. Others, who are already working on sex or gender-related topics, are hesitant to publish their views. Such a climate of fear and reticence serves no one. To find a way forward we need more knowledge, not less. Nearly 20 researchers from diverse fields, including neuroscience, psychology, immunology and cancer, have contributed to the series, which provides a snapshot of where scholars studying sex and gender are aligned — and where they are not. In time, we hope this collection will help to shape research, and provide a reference point for moderating often-intemperate debates. In practice, people use sex and gender to mean different things. But researchers studying animals typically use sex to refer to male and female individuals, as defined by various anatomical and other biological features. In studies involving humans, participants are generally asked to identify their own sex and/or gender category. Here, gender usually encompasses social and environmental factors, including gender roles, expectations and identity. © 2024 Springer Nature Limited

Keyword: Sexual Behavior
Link ID: 29281 - Posted: 05.02.2024