Altruism In Forest Chimpanzees: The Case Of Adoption

In the final chapter of NOT A CHIMP I deal briefly with the phenomenon of altruism and note that, while one or two investigators had made claims for the altruistic behaviour of chimps, in aiding others to secure food, or aiding researchers to reach out-of-reach objects, other influential authors claimed that chimps are unconcerned about the welfare of others. I noted the fact that, where altruism occurs in primates, it has less to do with whether or not the species concerned is closely related to man - as in the chimps - but more to do with socio-ecological factors. Hence, marmosets show altruism in food sharing perhaps because they are, like us, an allo-parenting species - they share the costs of bringing up baby.

Now Christophe and Hedwige Boesch, and others, who are from the Max Planck Institute in Leipzig, and have been studying the Tai Forest chimps in the Ivory Coast for over a quarter of a century, have documented adoption of very young orphaned chimps by both adult females and males. The adoption incurs genuine costs in food sharing, carrying the infant during skirmishes with neighbouring chimps, and stopping and waiting for slower juveniles during travel. What, they ask, could be the socio-ecological glue that holds adoption together such that it is shown in wild west African chimp societies but not among captured colonies of chimps - and not among the various East African groups of chimps that have been extensively studied? The authors point to the very high predation pressure upon the Tai chimps, by leopards. This, they say, has promoted strong within-group solidarity in the form of care for injured individuals and joint coalition defence. Once established, they say, this care for the welfare of others, and high level of defence cooperation, generalizes into new social contexts, including adoption.