High motivation toward food increases food-sharing in cotton-top tamarins.

In order to explore whether or not adult motivation influences transfer of food to infants in cotton-top tamarins (Saguinus oedipus oedipus), 2 experiments were carried out with 3 large captive family groups. Examination of (a) natural changes in food motivation during feeding, and (b) elevated motivation toward food by giving highly preferred items, showed that the adult monkeys shared food more when their own level of motivation was high. This suggests that food-transfer is not merely a consequence of adult satiation, but that matching sharing with high adult motivation is a mechanism which ensures that infants receive ample food, the best items, and also rare items of high quality.