Before revision: There is increasing evidence that fairness and generosity are not exclusive human traits. Indeed, several experiments on chimpanzees, monkeys and other mammals show an inequity-aversion behavior. Namely, if some valuable resource, e.g. food, is unevenly divided between two individuals, the one who gets a smaller share may reject the reward, and, in some cases, there can even be an attempt of the animal with the larger share at equalizing the division. Therefore, animals can deliberately lower their gain in name of an apparent sense of fairness. Here we show the emergence of generosity in a resource-gathering-and-sharing gameinspired by animal behavior .
After revision: Resource sharing outside the kinship bonds is rare. Besides humans, it occurs in chimpanzee, wild dogs and hyenas as well as in vampire bats. Resource sharing is an instance of animal cooperation, where an animal gives away part of the resources that it owns for the benefit of a recipient. Taking inspiration from blood-sharing in vampire bats, here show the emergence of generosity in a resource-gathering-and-sharing gameinspired by animal behavior .