We’ve known for a long time that chimps use tools. But we’re learning now that young chimps may be using their imaginations when playing with “toys.”

Richard Wrangham and a team of scientists have been noticing for years that young chimps sometimes carry sticks around the same way that young children carry dolls. The sticks are cradled like dolls, and even treated to the same games that adult chimps play with their babies. One time, a chimp was even observed creating a separate sleeping nest for its stick.

This has caused a stir because the team has also observed that young female chimps are twice as likely as young male chimps to play with sticks in this way. The young males are more likely to use sticks for poking. Does this mean that gender-based mothering behavior in young humans (as well as chimps) is a result of biology? Or does it confirm that young females, knowing they are females, are eager to emulate the adult females around them? There are many articles tackling this now, including this one by National Public Radio. What is your opinion?