AIMED THROWING AS A MEANS OF FOOD TRANSFER BETWEEN TUFTED CAPUCHINS (CEBUS-APELLA)

We examined aimed throwing as a means of food transfer in tufted capuc hins (Cebus apella). We conducted this research in three phases. In Ph ase 1 we provided food to monkeys in one of two groups housed 1 m apar t. We did not provide food to subjects in the second group. An observe r recorded each instance in which a subject in the first group threw f ood toward one in the second group. In Phase 2 we provided a group of capuchins with food and noted each instance in which a subject threw f ood toward an empty cage. In Phase 3 we provided food simultaneously t o two groups of capuchins and noted each instance of food-throwing bet ween them. In Phase 1 subjects in one group threw food toward subjects in a second group, which, when provided the opportunity, did not thro w food toward capuchins in the first group. Thrown food was either cau ght retrieved or lost on the test room floor The rate of throwing decr eased significantly when subjects were presented with an empty cage an d when both groups of subjects were given food. We propose that psycho logical processes which underlie aimed throwing and food sharing came into existence through convergent evolution in large-brained, extracti ve foraging primates. We further speculate that although a well-develo ped system of exchange, based on contingent reciprocity, may occur amo ng primates only in Homo, simpler transfer systems involving voluntary unidirectional passing of food from one individual to another appear to be more widespread among primates than previously thought and can b e expressed in rather unusual circumstances such as those in this expe riment.