Young female chimpanzees treat sticks as dolls: Growing evidence of biological basis for gender-specific play in humans##
ScienceDaily (2010-12-22) -- Researchers have reported some of the first evidence that chimpanzee youngsters in the wild may tend to play differently depending on their sex, just as human children around the world do. Scientists say female chimpanzees appear to treat sticks as dolls, carrying them around until they have offspring of their own. Young males engage in such behavior much less frequently. ... > read full article
This article elicited a "huh?" reaction from me when I first saw it. However, the results are derived from 14 years of aggregate data, is being supervised by Richard Wrangham, which means I am inclined to believe it. It would not be entirely preposterous for them to need so much observation time in order for them to be able to pick out a significant number of instances of a very particular behavior such as this.
Wired has their take on the story as well (wait, since when does Wired cover primatology?), which is also worth skimming over for the images at very least.