Don’t count out the Y chromosome just yet. Far from being in a state of decay, as some studies have suggested, a new study in Nature says the male chromosome in humans is actually evolving at a furious pace.
Study leader David Page of MIT sequenced the human Y chromosome back in 2003, and in the new study his team compares it to the male chromosome of chimpanzees. The scientists expected the two sequences to look very similar. However, while human and chimp DNA generally differ by less than 2 per cent, more than 30 per cent of the Y chromosome differed between the two species [The Times].
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African chimpanzees know how to handle wildfire, as DISCOVER noted last month. But lava is a different deal. Nyamulagira, a volcano in the Democratic Republic of the Congo, began to erupt over the weekend and threatened not only the people nearby, but also the endangered primates that live in the area. The southerly lava flow appears to have spared most human settlements and the mountain gorillas of Virunga National Park, but the native chimps haven’t been so lucky.
The 40 eastern chimpanzees that live on Nyamulagira itself could still be at risk if they are surrounded by lava, and as the plants they rely on for food become coated by abrasive volcanic ash. Park officials hope animals in the lava’s path will simply move away from it [New Scientist]. United Nations peacekeepers, who are in the Congo to protect civilians from the seemingly unending war there, have offered the country’s leaders the use of UN planes and helicopters to monitor the situation.
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When it comes to understanding fire, chimpanzees might have a leg up not only on the rest of the animal kingdom, but also on those of us in the human species who would sprint in the other direction at the sight of a blaze. A study published in the American Journal of Physical Anthropology argues that these primates don’t panic when the flames start, and could even understand the basics about how fire behaves.
Primatologist Jill Pruetz has been observing chimps in Senegal since 2001, but it was in 2006 that she first noticed how the animals reacted to wildfire. When people in the area set fires to clear the land, the chimps refused to tuck tail and run. “It was the end of the dry season, so the fires burn so hot and burn up trees really fast, and they were so calm about it,” Pruetz said of the chimps. “They were a lot better than I was, that’s for sure” [LiveScience].
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Last week, seemingly out of nowhere, Oklahoma State University president Burns Hargis pulled the plug on a federally funded research project that would have tested anthrax vaccines on baboons, and euthanized the primates at the experiment’s end. This week more details are beginning to come out regarding why Hargis made his call. Basically, his office says, they didn’t want to deal with possibly violent animal rights protesters.
The plan was to expose the animals to the spores of the attenuated Sterne strain of anthrax and eventually advance to the Ames strain — the fully encapsulated and virulent form of the bacterium that was used in the anthrax attacks of 2001 — and observe the pathobiology of infection. It was part of a collaborative multi-institutional NIH grant originally awarded for $12 million in 2004, and renewed in September of this year for another $14.3 million [The Scientist]. Oklahoma State would have hosted only a small part of the research, and the university’s animal testing committee approved the project unanimously.
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Birds, whales, monkeys, and other animals constantly demonstrate simple communication through a variety of sounds. But one thing that has always separated them from humans, scientists thought, is that they haven’t achieved syntax—stringing together multiple different sounds to create another meaning, or what we might think of as a sentence. Now, in a study published in yesterday’s Proceedings of the National Academy of Sciences, researchers argue that they have observed monkeys using these rudimentary rules of grammar.
Klaus Zuberbühler and his team previously established the meanings of specific calls among the Campbell’s monkeys in the Tai National Park of the Ivory Coast, like the sound they dubbed “krak,” which by itself means a leopard approaches. This time, however, they documented call combinations. The monkeys can vary the call by adding the suffix “-oo”: “krak-oo” seems to be a general word for predator, but one given in a special context — when monkeys hear but do not see a predator, or when they hear the alarm calls of another species known as the Diana monkey [The New York Times].
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If NASA ever wants to send astronauts on long-term space flights, it needs to know how radiation will affect the crew. Testing humans obviously isn’t going to happen, so NASA is funding a round of experiments to study how radiation effects monkeys, the first time monkeys have been used as test subjects by NASA in decades. The point of the experiments is to understand how the harsh radioactive environment of space affects human bodies and behavior and what countermeasures can be developed to make long-duration spaceflight safe for travelers beyond Earth’s protective magnetic shield [Discovery News]. The monkey studies will advance previous radiation experiments with rats and mice and will focus on how radiation affects the monkeys’ central nervous system.
Researchers will expose 18 to 28 squirrel monkeys with a small dose of radiation, similar to what astronauts would receive on a round trip flight to Mars. The monkeys, previously trained to perform a variety of tasks, will be tested to see how the exposure affects their performance [Telegraph] at different times after exposure to gamma rays. The monkeys will not be killed during the experiments, and after testing staff and veterinarians will look after them for the rest of their lives at Harvard Medical School’s McLean Hospital in Boston.
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Surprise, surprise. An independent analysis of the primate fossil that was unveiled amid extraordinary hype last May has found significant evidence that the lemur-like creature was not a direct ancestor of humans, after all. The 47-million-year old fossil described in May, which was given the scientific name Darwinius masillae and nicknamed Ida, was announced with unrestrained razzmatazz. She was the “eighth wonder of the world”, “our Mona Lisa” and an evolutionary “Rosetta Stone”, according to the researchers who unveiled her…. She was, they said, the “link” between us and the rest of the animal kingdom [The Guardian].
But Ida, who was the subject of both a book and a TV special that were released at the same time as the scientific paper describing the fossil, failed to wow many evolutionary biologists. Says Erik Seiffert, lead researcher of the new study: ”The suggestion that Ida [was]… specifically related to the higher primates, namely monkeys, apes and humans, was actually a minority view from the start. So it came as a surprise to many of us who are studying primate palaeontology” [BBC News].
Seiffert’s new analysis began with his attempt to identify another fossil primate, Afradapis longicristatus, which he found to be a close relation to Darwinius. The researchers then compared 360 specific anatomical features of 117 living and extinct primate species to draw up a family tree [AP]. The analysis showed that both primates are located on an early twig of the branch that produced lemurs, and far from the lineage that spawned monkeys and great apes [Wired.com]. What’s more, the researchers say that both species have no modern descendants.
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Humans typically feel uneasy when they see a very realistic human-looking robot or computer avatar, a phenomenon called the “uncanny valley” response. According to a new study performed with monkeys, that reaction might have an evolutionary basis.
Researchers hypothesize that the response stems from almost realistic images that signal HUMAN! to us, but then fail to live up to the initial excitement. The uncanny valley response has been documented in humans since the 1970s, and has been blamed for the unpopularity of some CGI films with realistic characters [like The Polar Express and Final Fantasy], and it is touted as the reason Pixar stuck to characters with cartoonish features [New Scientist].
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The tender interactions between human mothers and their newborn babies may have deep evolutionary roots: a new study found that rhesus macaque monkey mothers engage in strikingly similar behavior with their infants.
The researchers found that the mothers would gaze intently at their newborns, sometimes even taking their baby’s face with their hands and gently pulling it towards them to get an even closer look. They would also engage in “lipsmacking” – an affectionate form of expression, where the macaques rapidly open and close their mouths [BBC News]. Several videos taken by the researchers show that just like human babies, the infant monkeys responded to their mothers by mimicking their facial expressions and returning their stares.
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Humanity has a new matriarch: a hominid named Ardi who lived in Ethiopia 4.4 million years ago. Anthropologists have unveiled the results of 17 years of research on a new species named Ardipithecus ramidus, presenting a rich trove of fossils including the partial skeleton of the small-brained, 110-pound female. Ardi is 1.2 million years older than the famed “Lucy,” of the species Australopithecus afarensis, and experts say the find fundamentally changes our understanding of human evolution.
Study coauthor Tim White says that Ardi provides clues to what the last common ancestor shared by humans and chimps might have looked like before their lineages diverged about 7 million years ago…. But despite being “so close to the split,” says White, the surprising thing is that she bears little resemblance to chimpanzees, our closest living primate relatives [Time].
Ardi’s pelvis, leg, and feet bones indicated that she walked upright on two feet, but her opposable big toes suggest that she was also comfortable climbing trees. Her hand, arm, and shoulder bones indicate that she didn’t often swing through the trees, though; instead she probably walked on her palms along tree branches like some extinct apes. Based on Ardi’s anatomy, it appears that chimpanzees may actually have evolved more than humans — in the scientific sense of having changed more over the past 7 million years or so [Time].
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For two squirrel monkeys nicknamed Dalton and Sam, life has gotten a lot more colorful. Researchers used gene therapy to correct the color blindness of the two adult monkeys, giving them the ability to distinguish between red and green for the first time. The fascinating accomplishment suggests that scientists may someday be able to cure other kinds of blindness in humans. And because the treated monkeys were “middle aged”, it challenges the assumption that gene therapies cannot work in adults because their brain connections are too set in their ways to change beneficially [New Scientist].
The field of gene therapy, in which a malfunctioning gene in a patient’s body is replaced with a functional one, fell into disarray one decade ago following the death of an 18-year-old in a clinical trial. But since then scientists have regrouped, using animal studies to probe the technique’s safety. Last year, researchers progressed to the point of safety trials in humans for the treatment of one rare eye condition called Leber congenital amaurosis, and were able to dramatically improve the patients’ sight. Those results were stunning, but they were also achieved in children, whose still-growing brains can rewire themselves on the fly in response to new sources of visual stimuli [Wired.com].
In the new study, published in Nature, the researchers used a type of squirrel monkey in which the males lack a visual pigment called L-opsin. Its absence renders the monkeys color-blind, unable to distinguish reds and green. Most of the females, on the other hand, see in full color. So the scientists got to wondering: what would happen if they gave a boy squirrel monkey the same opsin that girls have [Scientific American]. They used a harmless virus to ferry in the gene that makes opsin, injecting the virus behind the monkeys’ retinas.
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Yawning is so contagious that even chimpanzees who watched animations of cartoon chimps yawning couldn’t resist the impulse, according to a new study in Proceedings of the Royal Society B. Study coauthor Matthew Campbell doesn’t think the chimps were “fooled” by the animations into thinking they were looking at real chimps, he explained that there was evidence that chimpanzees “process animated faces the same way they process photographs of faces”. He said: “It’s not a real chimpanzee, but it kind of looks like a chimpanzee, and they’re responding to that” [BBC News].
The chimps were tested by first showing them animated chimps making a variety of facial expressions, and then another set of cartoons with yawning chimps. Only the latter cartoons elicited the yawning response. Campbell says the findings could assist in the future study of empathy…. “We’re interested in using animation for presenting stimuli to animals, because we can control all the features of what we show them” [BBC News].
As for why yawns are so contagious, Campbell suggests that the phenomenon may have evolved to allow some animals “to coordinate activity better, resting when other individuals are resting” in order that they “can travel when it’s time to travel, eat when it’s time to eat” [Discovery News].
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Image: J. Devyn Carter. Still frames from the animated yawning.
As anyone who has a favorite (and least-favorite) musical artist knows, music can affect our moods. Now it seems it can do the same for cotton-top tamarin monkeys, but only when the music is composed specifically for them, according to a study published in the journal Biology Letters.
Except for one anomaly (they liked Metallica), the monkeys didn’t respond to samples of human music–but the tamarins did respond to cello music that was reminiscent of their natural calls. Cellist and composer David Teie studied recordings of both happy and upset tamarins, and used them as the bases for two different kinds of monkey music. “Basically I took those elements and patterned them the way we do normally with music,” he says. “You repeat them, take them up a [musical] third — you know, using the same kind of compositional techniques we use in human music.” He played the compositions on his cello and then electronically boosted them up three octaves, to a pitch that matched the monkeys’ voices [NPR].
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Imitation may be the sincerest form of flattery not just for humans, but for many primates. In human social interactions, people have an instinctive tendency to copy each other’s body language and mannerisms, and previous studies have shown that such imitation gives rise to friendly feelings. Now a new study has found that capuchin monkeys respond to imitation in the same way, suggesting that the behavior may date back to early in our evolutionary history. The subtle aping may promote the formation of social groups—building cooperation, reducing conflict, and aiding the survival of each individual [Scientific American].
To study the behavior in capuchin monkeys, which live in highly social groups of 30 or 40 individuals, the researchers gave each monkey a Wiffle ball — a lightweight plastic ball with holes in it. Monkeys typically poked the ball with their fingers, put it in their mouths or used it to pound on something. Each monkey was paired up with two human researchers, one that copied their ball-handling skills, and one that did not. When the balls were put away, the monkeys appeared to prefer the company of the like-minded ball handler [Reuters].
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Using the first known animal instruments, orangutans use leaves to make their voices sound deeper, perhaps thereby tricking predators into thinking the apes are bigger than they really are, according to a study published in the journal Proceedings of the Royal Society B.
Orangutans produce a noise known as “kiss squeaks” to let predators like snakes and leopards know that they’ve been spotted, and can use their lips and fingers or folded leaves to make the sound. To find out more about why the animals produce the noise, researchers recorded kiss squeaks between 2003 and 2005 near a research station … on the island of Borneo. The team noted whether the sounds had been made with hands, leaves, or lips alone [National Geographic News]. They found that squeaks made using only the lips had a higher pitch than those produced using hands, and that leaf-produced pitches had the lowest frequency and therefore the deepest sound.
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