A preliminary study of social behavior and pair-bonding in wild titi monkeys (Callicebus discolor) in Amazonian Ecuador	AAPA 2004
A. Di Fiore1and D.M. Schwindt2
1Department of Anthropology, New York University, and the New York Consortium in Evolutionary Primatology (NYCEP), 2Earth and Environmental Science Program, Department of Biology, New York University
Titi monkeys are one of three genera of platyrrhine primates that typically live in ‘monogamous’ social groups. The adult male and female in a group are considered to be ‘pair-bonded’, displaying behaviors such as tail-twining and vocal duetting that are presumed to reinforce the special relationship between them and to advertise their paired status to other animals in the population. As part of a collaborative project on the comparative socioecology of ‘monogamous’ platyrrhines, we collected data on the social behavior of adults in radiocollared groups of titi monkeys in Amazonian Ecuador. Specifically, we examined grooming relationships; patterns of initiation, maintenance, and termination of proximity between group members; parent-offspring interactions; coordination of group movement; and territorial behavior. Titis in our study population invariably lived in groups comprising a single adult pair plus dependent offspring. Preliminary data indicate that grooming is the most common type of social interaction, with bouts between pair-mates often lasting >1 hour. Pair-mates also spend more time involved in grooming each other than either does with dependent offspring, and the adult male is the most common recipient of grooming. While an entire group is generally spatially cohesive, the adult male appears to spend more time in close proximity to dependent offspring than the female. Adult males also appear to more commonly share food with dependents. Intergroup interactions and territorial displays are far less common in this population of titis than has been reported elsewhere. Together, these patterns of behavior have implications for the evolution of ‘monogamous’ social systems.