The muriqui have a reputation as being one of the gentlest, most social of the primates—so much so that they’ve been dubbed the “hippy monkey.”But even the sweetest of animals will turn murderous when deprived of basic needs—in this case, sex. New Scientist reports that a gang of six muriqui was spotted pulling a “Lord of the Flies” on an older male:
The victim, an old male, died an hour after receiving savage bites to his face, body and genitals. The observations, published this week in the American Journal of Primatology, show how lifestyles may dramatically alter the behaviour of a species.
So why would these peaceful creatures, close relatives of spider monkeys found only in the Atlantic forests of Brazil, turn to such savagery? NS explains:
The muriqui’s peaceful reputation stems mainly from northern populations that feed on abundant leaves, and where males patiently queue to mate with females.
But in the southern population where the attack took place, fruit is more widely available than in the north, and this may provide a clue to the assault, says Mauricio Talebi of the Federal University of São Paulo-Diadema, Brazil, who led the research.
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Just as humans and gorillas share a common evolutionary ancestry, the pubic lice that infuriate some members of the two species are also related. Pubic lice–known to scientists as Pthirus pubis and to most other people as “crabs”–are thought to have evolved from Pthirus gorillae, the structurally similar species that infests gorillas. Genetic analysis by David Reed at the University of Florida indicates that the lice lineages split about 3.3 million years ago, whereas it is believed that humans diverged from gorillas at least 7 million years ago. This suggests that “early humans somehow caught pubic lice from their gorilla cousins.”
But apparently the lousy parasite didn’t make the jump because humans and gorillas tried to reunite their bloodlines; no, University College London biologist Robin Weiss suspects that humans picked up crabs by hunting gorillas. Because a predator can easily pick up parasites from its prey, the lice could have jumped to early humans while they butchered gorillas for bushmeat. Some researchers say that HIV made its more recent jump from chimpanzees to humans the same way.
Image: Flickr / mrflip
We kid you not: Orphaned baby chimpanzees cared for by humans in a loving, attentive manner have been found to be more cognitively advanced than some human infants.
Authors of a new study in Developmental Psychobiology compared nine-month-old human babies to nine-month-old chimps who had received daily “mom sessions.” For 20 hours a week, humans would play with 17 of the orphaned infant chimps, helping them to develop motor skills and to “meet new challenges with curiosity instead of distress.”
The chimps were then given an IQ test, the same tool normally used to assess infant human development—and those receiving all the mommy time scored an average of almost 10 points higher than normal humans of the same age. Meanwhile, the 28 chimps raised in “standard care” scored an average of 7.5 points lower.
The chimpanzees who received “responsive care” continued to exhibit strong cognitive and emotional development throughout their youth. Those who received standard or institutional care, however—in which only physical needs were met, with no social or emotional care from human surrogate mothers—were less likely to become well-adjusted adults.
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Scientists were stunned when they first heard Bonnie whistle. The 30-year-old female orangutan at the Smithsonian National Zoo had never been taught to whistle, but she figured out the trick all by herself back in the 1980s, according to her caretakers. That makes her the first documented case of a primate spontaneously mimicking the sounds of another species—in this case, humans.
Though she can’t carry a tune, Bonnie seems to enjoy whistling and will usually happily comply when asked to do it. You can even watch her whistle on Youtube. The researchers, who published a paper on Bonnie in the journal Primates [subscription required], say she also taught another orangutan, Indah, how to whistle. Bonnie and Indah dispel the theory that orangutan vocalizations are only involuntary reactions to stimuli, and are mainly determined by evolutionary factors.
Instead, whistling orangutans suggest that orangutans can learn and teach each other new vocalizations. This would explain why separate populations of orangutans in the wild seem to maintain different repertoires of sounds—which can include screams, grumbles, barks, raspberries, and kiss squeaks.
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We know that whales fall in love, horses feel pride, and primates can even become embarrassed and envious. And now it appears that dogs get jealous, too. A new study out of the University of Vienna is the first time scientists have observed and documented envy in a non-primate species, though people who own dogs may have already seen it in action.
The research team asked 14 trained dogs to “shake” in a series of experiments. To test for jealousy, the researchers put the dogs in a room alone, or put them in the company of another familiar dog (either an acquaintance or another dog from the same household). And while the researchers didn’t offer the dogs a bone, they did give one or the other of the dogs either sausage or bread when they wanted to reward the dogs for performing the task. When the hungry dogs realized they were doing the same work but not getting any food in return, they became jealous of their companion, who was getting fed.
In fact, the dogs who were denied treat would eventually stop shaking the researcher’s hand entirely, and would look away from the researcher and even scratch, yawn, and lick their mouths.
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Scientists have taught monkeys to control a robotic arm with their thoughts. No, the primates aren’t telekinetic—they have computerized brain implants—but their newfound ability is one of the most impressive examples yet of linking brains to machines.
The research team, led by Andrew Schwartz from the University of Pittsburgh, used two macaques in their study. They planted a tiny computer grid over each primate’s motor cortex, an area of the brain that normally controls the monkey’s arm movement. Then they mounted the robotic appendage, complete with elbow and shoulder joints and a claw for grabbing, on each animal’s shoulder where its normal arm is attached. The computerized implant would read the monkeys’ minds—or rather, it would pick up on their motor neurons firing—and translate those electrical impulses into the appropriate maneuver in the machine.
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