received help recently. The vampires' reciprocal altruism must be particularly effective since the bats, despite the risk of death after three bloodless nights, can live for 15 years. If social altruism has evolved among vampire bats, there is no reason why it could not also emerge among primates. And indeed it can be seen at work in the coalitionary politics of male chimpanzees, where the alpha male depends on allies to preserve his dominance of the male hierarchy. The biologist Robert L. Trivers, who first showed how reciprocal altruism could be favored by natural selection, suggested that in people a wide range of sophisticated behaviors grew up around it, including cheating (failure to return an altruistic favor to the giver),
Was this article helpful?