Wild chimpanzees show population-level handedness for tool use
- *Department of Conservation and Science, Lincoln Park Zoo, Chicago, IL 60614; †Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637; ‡Division of Psychobiology, Living Links Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322; and §Department of Psychology, Berry College, Mount Berry, GA 30149
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Communicated by Frans B. M. de Waal, Emory University, Atlanta, GA, July 14, 2005 (received for review May 9, 2005)
Abstract
Whether nonhuman primates exhibit population-level handedness remains a topic of considerabe theoretical and empirical debate. One continued subject of discussion is whether evidence of population-level handedness in primates is confined to studies in captive animals or whether it is in both captive and wild subjects. Here, we report evidence of population-level handedness in wild chimpanzees for a tool-use task known as “termite-fishing.” We subsequently compared the handedness for termite-fishing with other published reports on handedness for nut-cracking and wadge-dipping and found task-specific differences in handedness. Last, when combing all of the published data on tool use in wild chimpanzees, we show that hand preferences are heritable. Contrary to previous claims, our results demonstrate that populationlevel handedness is evident in wild chimpanzees and suggest that the antecedents of lateralization of function associated with hand use were present at least 5 million years ago, before the Pan-Homo split.
Footnotes
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↵ ¶ To whom correspondence should be addressed at: Division of Psychobiology, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322. E-mail: lrcbh{at}rmy.emory.edu.
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Author contributions: E.V.L. designed research and performed research; W.D.H. analyzed data; and E.V.L. and W.D.H. wrote the paper.
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Abbreviation: HI, handedness index.
- Copyright © 2005, The National Academy of Sciences
