It’s hard to imagine having more fun in the name of science: In a new study, researchers tickled young chimpanzees, bonobos, gorillas, orangutans, and even a few human babies, and recorded the vocalizations that resulted. Primatologist Marina Davila Ross wanted to examine the evolutionary history of laughter, so she and her colleagues recorded the sounds produced when they tickled 22 great apes and 3 human babies, picking the usual sensitive spots: armpits, palms, feet, and necks.
Scientists have known that great apes vocalize when tickled at least since Charles Darwin’s time. But it was unclear whether these sounds were actually related to human laughter. Now, researchers … have concluded that laughter has been evolving in primates over the last 10 to 16 million years, since at least the last common ancestor of humans and modern great apes [Wired.com].
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When a banana is at stake, a low-status capuchin monkey may deceive the other monkeys in his troupe in order to get his hands on that tasty fruit. A new study of monkeys in an Argentinian national park found evidence that lowly monkeys give spurious alarm calls in order to scare off more dominant monkeys competing for food.
Tufted capuchin monkeys give a two-syllable “hiccup” call when they detect danger, like an approaching ocelot. Lead researcher Brandon Wheeler was studying a group of capuchins eating food left on platforms constructed in trees, when he noticed some of the monkeys made the calls when predators weren’t around. “They were giving the same calls that they give for cats extremely frequently,” he says. “When they do, other individuals often run out off the platform, which potentially leaves [the platform] available for whoever called to jump in to get some food” [ScienceNOW Daily News].
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Five small monkeys that glow green under ultraviolet light are providing a beacon for medical research. Researchers introduced a jellyfish gene that codes for a fluorescent protein into the embryos of marmosets, and found that the resulting monkeys expressed the gene in all the cells of their body, including their egg and sperm cells–which means the genetically engineered primates can naturally pass on the foreign trait to their offspring. While creating a family of glowing monkeys doesn’t have obvious benefits for medical science, researchers say the study was really just a proof of concept.
Researchers have added genes to rhesus macaques before, but the new work with marmosets is the first to document that monkeys can pass an inserted gene along to future generations. That’s important because it opens the door to creating colonies of such “transgenic” monkeys by breeding, which would be far simpler than the cumbersome process of making each animal from scratch by inserting genes into embryos [AP]. Now that researchers have mastered the technique, they hope to create transgenic monkeys that carry genes associated with such diseases as Parkinson’s and Lou Gehrig’s disease.
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A small, lemur-like creature may have been an early ancestor of monkeys, apes, and humans. A magnificently preserved fossil dating from 47 million years ago reveals an animal that had, among other things, opposable thumbs, similar to humans’ and unlike those found on other modern mammals. It has fingernails instead of claws. And scientists say they believe there is evidence it was able to walk on its hind legs [ABC News].
In a study that will be published in the journal PLoS ONE tomorrow, researchers will report that this extraordinary fossil could be a “stem group” from which higher primates evolved, “but we are not advocating this” [The New York Times]. The fossil was first discovered in 1983 in the Messel Shale Pit, an old quarry near Frankfurt, Germany that has long been a World Heritage Site because of its rich fossil beds. The specimen was excavated by private collectors but was then divided into two parts and sold; it was only two years ago that scientists reassembled the complete fossil and began studying it.
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A neuroscientist whose car was firebombed by violent animal rights activists has decided to fight back, at least in the court of public opinion. The UCLA professor, David Jentsch, has formed a group called UCLA Pro-Test, and is organizing a rally in support of animal testing. “People always say: ‘Don’t respond. If you respond, that will give [the attackers] credibility,’” Jentsch, 37, said in a recent interview in his UCLA office. “But being silent wasn’t making us feel safer. And it’s a moot point if they are coming to burn your car anyway, whether you give them credibility or not” [Los Angeles Times].
UCLA Pro-Test, named after a similar group in the United Kingdom, wants to show its support for animal research that is conducted in a humane and regulated way. Jentsch studies schizophrenia and drug addiction, and works on both rodents and vervet monkeys.
The Animal Liberation Brigade took credit for bombing Jentsch’s Volvo as it sat in his driveway in the early morning hours of March 7. The activist group wrote in an Internet posting: “The things you and others like you do to feeling, sentient monkeys is so cruel and disgusting we can’t believe anyone would be able to live with themselves…. David, here’s a message just for you, we will come for you when you least expect it and do a lot more damage than to your property” [Los Angeles Times].
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When the earliest human ancestors left the trees and struck out to make a new life for themselves on the ground, there was no going back, a new study suggests. Researchers examined the ankle bones of those early people and compared them to those of chimpanzees, and say that by 4 million years ago the proto-humans were no longer adapted for skillful tree climbing.
Researchers estimate that the chimpanzee and human lineages split about 5 million to 7 million years ago. Yet experts are divided about what happened next to the first hominins, as members of the human subfamily are called. One group argues–based on evidence that early members of the human line lived in woodland environments and had curved fingers and toes that were good for climbing–that the first hominins spent some time in the trees even as they adapted to their new ground-dwelling lifestyle [ScienceNOW Daily News]. The other faction believes that when humans began to walk upright they quickly lost their arboreal ways, and argues that their arms and legs were more human-like than ape-like.
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In the remote limestone mountains on the eastern edge of the island of Borneo, a large population of orangutans has been living quite happily, far from human settlements and untouched by the trouble that we humans can bring. Based on a rumor of the primate outpost researchers traveled for days through the mountains, and eventually discovered 219 orangutan nests in the forest, which they say could indicate that as many as 2,000 orangutans live there.
With only about 50,000 orangutans remaining in the wild, conservationists say it’s a rare piece of good news for the endangered species. “We rarely have something positive to report in the conservation world. Most of the stories are about declining population or animals dying. It’s all pretty negative,” said Erik Meijaard, a senior ecologist with the U.S.-based Nature Conservancy. “So to find a substantial population of potentially several hundred to several thousand animals is very exciting” [CNN].
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Human females may get offended at dates who expect a little something extra after they buy a steak dinner, but for chimpanzees, the exchange may be a fair one [Reuters]. A new study of a chimp community living in the western African nation Côte d’Ivoire has found that males regularly share meat from their hunting expeditions with females, and get sex in return.
The researchers observed males sharing meat with females in estrus, who have sexual swellings that indicate their current fertility. More surprising was that males shared meat with females that didn’t have sexual swellings, perhaps in hopes of future success, the researchers say. The sex “may not necessarily occur immediately—it could occur sometime in the future,” said study co-author Cristina M. Gomes [National Geographic News]. The findings, she says, support the theory that chimps can engage in long-term planning, anticipating future events and remembering past interactions.
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Human toddlers aren’t the only ones who throw tantrums to get their way, and human parents aren’t the only ones who give in, guiltily, to avoid causing a scene. Researchers have found that rhesus macaque monkeys engage in very similar behavior, in which baby monkeys pitch screaming fits until their mothers give in and feed them in order to prevent attacks from irritated onlookers. Explains lead researcher Stuart Semple: “The baby monkeys’ cries are high-pitched, grating and nasty to listen to – not just to their mother but to animals nearby. And we found that the way mothers respond to their crying infants is affected by who is around them at the time” [BBC News].
Researchers observed the behavior of wild monkeys on the island of Cayo Santiago, Puerto Rico. When a baby wanted to nurse but the mom wasn’t willing the shrieks started up, and researchers then monitored the actions of baby, mom, and any other monkeys within six feet. The researchers noted that during a temper tantrum the onlookers seemed bothered and on occasion made threatening gestures, or even chased, grabbed or bit the mother or the infant. Most of the aggression came from monkeys that weren’t close relatives and outranked mom in the social hierarchy. Her relatives proved more tolerant [Science News].
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A belligerent chimpanzee in a Swedish zoo that stockpiles projectiles to hurl at visitors may be the first definitive proof that some animals can plan far ahead, researchers say. For years a male chimp named Santino has collected stones and other potential missiles into caches around his enclosure, which he returns to hours later when he wants to attack visitors. Researchers say the behavior proves that Santino was planning for the future because he collected the stones in a calm state, prior to the zoo opening in the morning. The launching of the stones occurred hours later – during dominance displays to zoo visitors – with Santino in an “agitated” state [BBC News].
Lead researcher Mathias Osvath says the behavior reveals an advanced animal intelligence. “These observations convincingly show that our fellow apes do consider the future in a very complex way…. It implies that they have a highly developed consciousness, including lifelike mental simulations of potential events” [AP], he says.
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The nation’s largest primate research center has been accused of mistreating its monkeys and apes by the Human Society, which sent an undercover investigator to work at the research center for nine months. The New Iberia Research Laboratory houses more than 6,000 primates, including rhesus macaques and several hundred chimpanzees, on a sprawling 100-acre site in rural Louisiana. On its website, the Humane Society has posted clips of the video footage that show monkeys with open wounds, chimps being sedated with dart guns and falling from their perches onto the floor [The Scientist].
The Humane Society filed a complaint with the U.S. Department of Agriculture, listing 328 possible violations of the Animal Welfare Act. In response, U.S. Agriculture Secretary Tom Vilsack ordered an investigation of the facility. “In light of the video evidence presented today, I am ordering a thorough investigation of animal welfare practices at New Iberia Research Center,” Vilsack said. “If the allegations prove to be true, the American public can expect the perpetrators to be held fully accountable. I take the protection of animals very seriously, and will do my utmost to fully enforce the Animal Welfare Act” [The Times-Picayune].
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A particularly clever band of chimpanzees living in one area of the Congo basin have found a better way to fish for food in termite mounds. Zoologists have long known that chimps eager for a tasty termite snack use a short stick, which is thrust into the termites’ nest. The insects bite on the intruding probe and are then extracted and slurped down [AFP]. But chimps living in an area called the Goualougo Triangle in the Republic of Congo have been observed crafting more complex tools that increase their haul of insect morsels.
Instead of using a simple pointed stick, lead researcher Crickette Sanz says these chimps modify their tools by making a special brush tip. To make their rods, the chimps first picked some stems from the Marantaceae plant and plucked off the leaves. “They then pulled the herb stems through their teeth, which were partially closed, to make the brush and they also attended to the brush by sometimes pulling apart the fibres to make them better at gathering the termites,” Dr Sanz added [BBC News].
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The U.S. House of Representatives voted yesterday to ban interstate trade of primates, following last week’s attack of a woman in Connecticut by a chimpanzee who’d been used in commercials and kept as a household pet. The Captive Primate Safety Act would not outlaw owning chimpanzees and other [primates] [MSNBC], but acquiring them would become more difficult. The legislation, which passed 323 to 95, would prohibit interstate sale or purchase of monkeys and apes, which include chimpanzees and orangutans, as well as marmosets and lemurs [Reuters].
The legislation applies only to the sale of primates as pets, and would have no impact on zoos or researchers. There may be as many as 15,000 primate pets in the United States. Only 20 states prohibit keeping them as pets, and there is no federal law against it [The New York Times]. The Humane Society of the United States has said that over the past four years there were more than 40 incidents involving primates escaping and injuring humans [Reuters].
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Capuchin monkeys not only have the capacity to use tools, they also know which tool is best for the job at hand, according to a new study. Researchers observed capuchin monkeys in the wild testing out different stones and consistently settling on the heaviest, sturdiest stone to crack open palm nuts. Although anecdotal reports existed before, the new study is the first to systematically document tool use in capuchin monkeys. Because capuchins last shared a common ancestor with humans approximately 35 million years ago, the team writes, the capacity for stone-tool use evolved earlier than thought [New Scientist].
Researchers studied eight wild capuchins living in a forested area of Brazil. In several different trials, researchers planted two or three different rocks, of varying hardness, size, and weight, near where the monkeys were feeding. The choices ranged from crumbly sandstone to tough quartzite, with some artificial stones that the monkeys would not normally encounter also thrown in the mix. Capuchins chose the most effective stone for cracking nuts more than 90 percent of the time in four conditions. That figure fell slightly to 85 percent when the monkeys selected from artificial stones of the same size and different weights [Science News].
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Female macaques are much chattier than male macaques, according to a new study. The researchers say vocal communication is an important part of macaque social bonding and the findings may reflect similar patterns in the evolution of human language. Klaus Zuberbühler, who studies primate communication, says social animals communicate to resolve the constant tension between a “need to compete and a desire to cooperate” [New Scientist].
The researchers studied macaques living on Cayo Santiago island off Puerto Rico, and for three months they followed a group of macaques that consisted of 16 females and 8 males. Friendly monkey chit-chat included a variety of grunts, coos, and girneys (nasally whines, usually between mother and infant). The researchers counted the social vocalizations, excluding those that were used only to indicate food or predators, and found that females vocalized 13 times more often than the males. Researcher Nathalie Greeno says, “The results suggest that females rely on vocal communication more than males due to their need to maintain the larger social networks” [News Scientist].
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