Chimpanzees Have Culture!
This had always been suspected, because different populations of chimps have different behaviors, but it's never been totally certain whether it was due to environmental pressures or quirks of culture.
Victoria Horner, a primate researchers at the University of St Andrews and the Yerkes National Primate Research Center, and her colleagues designed a clever experiment to see if chimps do have culturally transmitted behaviors.
The researchers designed a box that would have some food placed in it. The food could be accessed in two ways, either lifting it up or sliding it. They then taught one chimpanzee to open it by lifting, and another in a different area by sliding.
They then let a different chimp, the student, watch while the first, the teacher, demonstrated how they were trained to open it. Once the new chimp had learned how to open the box, the first was removed and another new chimp brought in, who then became the student. This was repeated through six "generations".
The behavior was transmitted nearly perfectly. One chimp who had been trained to slide lifted the box once, but his student learned to slide anyway. That's a nearly 99% accuracy at passing learned behaviors down through generations, which is far better than could be achieved by each generation relearning how to use the box, showing conclusively that chimpanzees have culturally-inherited behaviors.
This isn't very surprising, at least not to me, because the anecdotal evidence has always been in favor of chimps being able to learn, and it would be more surprising if our closest relative didn't have some kind of culture, since we'd have to have developed it all on our own. But it's good to have evidence outside of stories.
(Abstract available here: http://www.pnas.org/cgi/content/abstract/0606015103v1)