ABSTRACT
In biological thought, reciprocity is surprisingly new, first analyzed in detail by Robert L. Trivers, in a landmark research paper published in 1971 and titled "The evolution of reciprocal altruism."Food sharing—beyond parents helping out their offspring—is very rare among mammals generally. In addition to vampire bats, it has been observed only among African wild dogs, hyenas, chimpanzees, and human beings. But then, food-sharing isn't the only avenue for reciprocity. However, bee-eaters, bats and baboons offer some of the clearest examples of reciprocity among animals. The fact that reciprocity does not require genetic closeness even suggests a new way of looking at domesticated animals: perhaps they have been selected as much for reciprocating with Homo sapiens as for deferring to them. A large proportion of human social behavior might well be encompassed and, in a sense, explained, by adding together the combined effects of kin selection and reciprocity.
