Chimps have been known to use tools before, to crack nuts for instance, but this use of spear-like weapons to attack other animals is completely new. Anthropologists from Iowa State University observed the apes at a site in Senegal. They say the chimps gnaw at sticks to sharpen them, then thrust them into tree hollows to hunt out small nocturnal mammals called bushbabies. One of the scientists who observed this, Jill Pruetz, says the innovative apes were predominantly females or the very young. I asked her why.
JILL PRUETZ: "When I saw the behaviour the most, that was during a time when the chimps ranged around as one cohesive group. I think it was a response by immatures and females to competition within the group. So they can't outcompete adult males in terms of resources, so I think this is just an innovative way of solving a problem in terms of food availability."