Hunting & human origins

A chimpanzee gazes as if in deep thought.

tumblr_mk8eha0WRy1r98cn7o1_1280Some chimps are exceptionally gifted at their jobs. Some are unremarkable or uninterested. Some are cheaters.

Ratios of nitrogen isotopes in cartilage and bone tissue pretty clearly establish the gifted hunters (who have higher δ15N ratios because they eat more meat). I’m fascinated by the speculations of Geraldine Fahey and colleagues, who gathered this data on chimps at Taï National Park, Côte d’Ivoire:

High rank is not necessarily a prerequisite for hunting ability; a variety of nonspecific special qualities or characteristics also may result in an individual chimpanzee being an impact hunter. The three gifted hunters at Taï stood out as being self-confident (Brutus), keen (Macho), and intelligent (Ulysse). At Taï, observational evidence suggests some females are more successful at obtaining prey because of their affiliative behavior with hunter males; the major role of these females is to enforce the social rules favoring hunters, and therefore, gaining meat becomes a common interest for these females and the hunter males. Gomes and Boesch also found that female chimpanzees at Taï copulated more frequently with males who shared meat with them in the long-term. In addition, Mitani and Watts suggested that the risk-taking demonstrated during a hunt enables males to assess each other’s reliability; correspondingly, hunting likely played a role in the development of collaborative abilities, which are important in strategic territorial and predator defense in both chimpanzees and humans. (PNAS, 25 March 2013)

Photo: Frank Wouters via Wikimedia Commons

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