Boesch / Oral

Hunting, Tools, and Sociality: A new evolutionary scenario for chimpanzees and humans

Boesch Christophe
Max Planck Institute for Evolutionary Anthropology
Leipzig, Germany

     Chimpanzees and humans possess in common three behavioural properties that distinguish them from the rest of the primates and mammals: They are the only species in which all know living populations use regularly many different types of tools, hunt regularly at least a few mammal species for meat, and live in large groups with a flexible fission-fusion social structure. If some models of human evolution have considered one or two of these behavioural patterns, none has stressed the importance of the simultaneous presence of the three of them within the chimpanzee-human clade. I propose here an evolutionary scenario of the evolution in chimpanzees and humans of these three abilities and explain how this was possible thank to the appearance of new cognitive capacities in this clade.
     For flexible tool use and hunting to evolve, the acquisition of a more elaborate understanding of causality as well as some notions of a theory of mind is required. These cognitive abilities progressively appeared in our common ancestors when they started to hunt arboreal prey for meat within flexible fission-fusion social groups. The flexibility required to live in a fission-fusion social structure was an important precondition for the acquisition of an elaborate understanding of causality and for being able to adopt the perspective of the prey within trees, both abilities essential to hunt successfully. Once those cognitive abilities are acquired, it became possible to anticipate the benefit of tool use in novel situations, which led to both a more flexible tool repertoire and more complex tool uses.

Boesch, C. and Boesch-Achermann, H. 2000. The Chimpanzees of the Taï Forest: Behavioural Ecology and Evolution. Oxford: Oxford University Press.