Payment for labour in monkeys

Cooperative hunting, in which several individuals pursue prey but only one makes a capture, is central to theories of human social and moral evolution. But among other primates, it is known only from the chimpanzee and a large-brained neotropical monkey, the capuchin. It probably evolved through either mutualism, in which two or more cooperators benefit simultaneously, or reciprocal altruism, in which one favour is repaid by another. We have found that brown capuchins (Cebus apella) share rewards obtained by a joint effort more readily than rewards obtained individually. Even if hunting in the field involves selfish opportunism, this food incentive will greatly enhance the persistence of cooperation.