Food sharing and the development of feeding behavior in Saguinus imperator, the emperor tamarin (Family: Callitrichidae)

This thesis describes a longitudinal study on the food sharing behavior in a captive family group of emperor tamarins (Saguinus imperator subgrisescens). In addition to the beggar-initiated transfers of food observed in some mammalian taxa, referred to as passive food sharing, callitrichids display a unique type of transfer, called active food sharing, in which the possessor of a food item initiates exchanges to infants with a set of stereotyped behaviors. This study investigated the effect of early social bonding, as measured by infant care behaviors, on the pattern of active and passive food sharing. The data show that active food sharing signals were not given by adults when there were no infants in the group. Two nonbreeding adult males were responsible for the majority of the food sharing directed to infants, and almost all of the active food sharing. The females in the group were observed to share food with infants, but were more likely to passively share than actively share. Using matrix permutation methods, it was determined that the correlation between the pattern of infant care behaviors and food sharing was not significant for the data set as a whole, but there were significant correlations between several of the infant care behaviors and food sharing for one of the four infants studied. Descriptions and sonagrams of a number of emperor tamarin vocalizations are presented, included two food-associated calls, which appear to have a number of similarities to the two food-associated calls described for several other tamarin species.