SOME 4000 years ago, chimpanzees were using stone tools to smash nuts in the west African rainforest. The discovery, the earliest known use of technology by chimps, could indicate we share a common tool-wielding ancestor. It also opens the door to archaeological studies of chimpanzee tool use.
When Julio Mercader of the University of Calgary, Canada, and his colleagues dug out a 4300-year-old site in Tai National Park, Ivory Coast, they found a variety of worked stone fragments. A few are clearly of human origin, as they show systematic efforts to flake rock to form edges. However, most of the…
