Observations of infant conflict and avoidance in San Martin titi monkeys (Plecturocebus oenanthe).

Conflict between caregivers and infants typically centers on disagreements over the amount and frequency of care provided. Prior research has identified many variables that impact patterns of mother-infant conflict. These include wide-ranging factors such as individual temperament, reproductive status, and availability of resources. By contrast, no studies have investigated the variables that influence father-infant conflict. To better understand the nature of caregiver-infant conflict in a species with obligate biparental care, I observed two groups of San Martin titi monkeys inhabiting disturbed secondary forest fragments in the San Martín region of Peru. Using instantaneous focal sampling of infants, I recorded physical conflict between infants and caregivers and instances of infant avoidance (leaving the infant) by adult males. I summarized data as the percentage of records in which these activities occurred for each focal day and report the estimates for caregivers. I further calculated mean percentages by month of infant age to assess the relative timing of infant conflict, for each group and age/sex class, and infant avoidance by males. Percentages of conflict and avoidance were markedly higher in the larger group living in a smaller habitat than in the other group. This pattern occurred across all age/sex classes. In both groups, the greatest amount of infant conflict occurred with siblings. I discuss the substantial variation in conflict and avoidance in relation to the various socioecological conditions that may have played a role. This study provides an in-depth description and exploration of parent-offspring and sibling conflict, which has not been examined previously in this species.