Abstract

Although tool use is known to occur in species ranging from naked mole rats [1Shuster G. Sherman P.W. Tool use by naked mole rats.Anim. Cogn. 1998; 1: 71-74Crossref Scopus (14) Google Scholar] to owls [2Levey D.J. Duncan R.S. Levins C.F. Use of dung as a tool by burrowing owls.Nature. 2004; 431: 39Crossref PubMed Scopus (27) Google Scholar], chimpanzees are the most accomplished tool users [3Whiten A. Goodall J. McGrew W.C. Nishida T. Reynolds V. Sugiyama Y. Tutin C.E.G. Wrangham R.W. Boesch C. Charting cultural variation in chimpanzees.Behaviour. 2001; 138: 1481-1516Crossref Scopus (321) Google Scholar, 4McGrew W.C. Chimpanzee Material Culture: Implications for Human Evolution. Cambridge University Press, Cambridge, UK1992Crossref Google Scholar, 5Beck B. Animal Tool Behavior: The Use and Manufacture of Tools by Animals. Garland Press, New York1980Google Scholar]. The modification and use of tools during hunting, however, is still considered to be a uniquely human trait among primates. Here, we report the first account of habitual tool use during vertebrate hunting by nonhumans. At the Fongoli site in Senegal, we observed ten different chimpanzees use tools to hunt prosimian prey in 22 bouts. This includes immature chimpanzees and females, members of age-sex classes not normally characterized by extensive hunting behavior. Chimpanzees made 26 different tools, and we were able to recover and analyze 12 of these. Tool construction entailed up to five steps, including trimming the tool tip to a point. Tools were used in the manner of a spear, rather than a probe or rousing tool. This new information on chimpanzee tool use has important implications for the evolution of tool use and construction for hunting in the earliest hominids, especially given our observations that females and immature chimpanzees exhibited this behavior more frequently than adult males.