Date of Award

Spring 2010

Degree Type


Degree Name

Master of Science (MS)

Graduate Group


First Advisor

Eduardo Fernandez-Duque


Adult titi monkeys (Callicebus spp.) form strong pairbonds and reside in socially monogamous groups. In addition, adult males are heavily involved in infant care, exhibiting a degree of direct investment unusual even among primate species with paternal care. Most of the research exploring the nature of these social bonds has focused on captive populations, and data on wild titi populations are limited. In particular, data quantifying the pairbond and exploring the costs of infant care are rare for wild titi monkeys. I analyzed data from two groups of titi monkeys (Callicebus discolor) in Yasuní National Park and Biosphere Reserve and quantified the affiliative social interactions between the adult male and the adult female in the group to determine 1) the frequency and type of affiliative behaviors exhibited by pairmates, 2) whether there is evidence for sex differences in maintenance of affiliative behaviors and proximity, and 3) whether there is evidence of social costs within a pair during the period when infant care is provided. The most frequent affiliative behaviors involved pairmates resting in close proximity to each other. In addition, males and females spent significantly less time within five meters of each other when they were providing direct infant care, consistent with the prediction that infant care may correlate with a decrease in affiliative behaviors between pairmates. Although no solid conclusions can be drawn from this preliminary study given the small sample size, this research provides data suggesting that the presence of a dependent infant may influence the quality of the relationship between pairmates.