The capuchin monkeys of Serra da Capivara National Park in Brazil are well known for using rocks. They use them as hammers to crack open nuts. They use them for digging. They even use them to show off to potential mates. Now scientists report that they also spend time banging stones together, for no clear reason, producing sharp-edged stone flakes that are just like some of the first tools of early humans. They don’t use these flakes, so they are clearly not trying to produce them. But the flakes do show that neither the human hand nor brain is necessary for making such artifacts.
Tomos Proffitt, a researcher at Oxford who has studied early human tools produced in Africa, and his colleagues in England and Brazil, reported the observations and an analysis of the rock flakes in the scientific journal, Nature.