Health & Science

Protecting chimpanzees from experiments

Captive chimpanzees may soon be placed on the list of endangered species, restricting their increasingly controversial use in medical experiments and show business. A new proposal from the U.S. Fish and Wildlife Service would give the 2,000 chimpanzees currently captive in the country the same protected status as their wild counterparts in Africa. Research on chimpanzees has been crucial for developing vaccines for hepatitis A and B and treatments for certain cancers in the past, but demand has dwindled. “There’s an emerging consensus that chimps and other great apes are no longer necessary for most—if not all—forms of medical research,” Fish and Wildlife Director Dan Ashe tells ScienceNews.org. The National Institutes of Heath is already considering retiring its 450 chimpanzees. Populations of wild chimpanzees have dropped by 65 percent over the past 30 years due to habitat loss and hunting; fewer than 300,000 remain. Yet conservationists say many Americans don’t realize that wild chimps are endangered because they see captive ones so often on television and in movies. Animal-rights activists have also criticized the U.S. for being the only developed country that still uses apes for research. Primatologist Jane Goodall called the new ruling “an important step toward saving our closest living relative.”

A prostate diet

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One in six men in the U.S. will be diagnosed with prostate cancer in their lifetime, and one in 36 will die of it. But a new study shows that a change in diet can help men with prostate cancer live longer. For eight years, researchers tracked the diets of more than 4,500 men who had been diagnosed with localized prostate cancer. They found that those who replaced 10 percent of the calories they typically got from carbohydrates, such as rice, bread, and sugary treats, with vegetable fats, like olive oil, after their diagnosis were 29 percent less likely to have their cancer spread to other parts of the body—and 26 percent less likely to die over the eight years—than those who didn’t change their diets. Eating an extra ounce of nuts every day was linked to an 18 percent reduced risk of their cancer metastasizing. Because obesity has been linked to prostate cancer death, when a man is diagnosed, “a lot of doctors will simply say, ‘Cut out fat,’” to lose weight, Duke University urologist Stephen Freedland tells Reuters.com. But vegetable fat may actually help prevent the cancer from spreading by increasing levels of antioxidants and decreasing inflammation.

How depression fuels obesity

If feeling sad makes you reach for an extra helping of ice cream, your taste buds may be more to blame than your willpower. A new study shows that intense feelings can make us more sensitive to taste but less sensitive to how much fat we’re consuming. German researchers recruited mildly sad or anxious volunteers and had them watch a happy, sad, or boring video clip. They also asked them to taste samples of a creamy drink containing different amounts of fat and to try a range of bitter, sweet, and sour flavors. They found that watching the happy or sad clip heightened volunteers’ sensitivity to flavor, but their ability to tell how much fat was in the drink “got much worse,” Rutgers University researcher Paul Breslin tells NPR.org. Volunteers who watched the boring clip showed no change in any of their tasting abilities. The findings may help explain why people often gain weight when they’re depressed. “They may be inadvertently eating more fat,” Breslin says, because their low mood impairs their ability to taste it.

Did primates originate in Asia?

A 55-million-year-old fossil unearthed in China could recast our understanding of primate evolution. The tiny, mouse-size skeleton predates any similar finding by 8 million years and “differs radically from any other primate, living or fossil, known to science,” paleontologist K. Christopher Beard of the Carnegie Museum of Natural History tells The New York Times. Researchers believe the animal, named Archicebus achilles, lived at the time when the earliest ancestors of modern monkeys, apes, and humans split from a lineage that evolved into tarsiers, which are small, nocturnal animals with large eyes that live in Southeast Asia. The fossil “looks like an odd hybrid” of the two lineages, Beard says, “with the feet of a small monkey; the arms, legs, and teeth of a very primitive primate; and a primitive skull bearing surprisingly small eyes.” The anatomy of the creature, which would have lived at a time when rain forests predominated, suggests it was “a kind of frenetic animal,” Beard says, “anxious and agile, climbing and leaping around.” Found a decade ago, the skeleton took years to classify. Its discovery in Asia bolsters a theory that primates originated there before migrating to Africa, where the first Homo sapiens arose just 200,000 years ago.