If you have any juvenile chimps on your Christmas list, a new study has made your shopping a breeze. Researchers have observed wild chimps using sticks as toys, and boy and girl chimps treat the sticks very differently, CNN reports. Young female chimps appeared to treat the sticks like dolls, mimicking how their mothers care for infants. Male chimps also sometimes treated their sticks like dolls, but were more inclined to use them as weapons.
"Sex differences in juvenile stick-carrying did not result from females observing their mothers carrying sticks, since mothers never carried sticks," the study found. "Instead, youngsters apparently learned socially from each other. Such juvenile traditions have previously been described only in humans." The authors suggest that the behavior may have evolved to help chimps become better mothers.
(Read more anthropologist stories.)