1Department of Anthropology, Stony Brook University, 2Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina, 3Centro de Investigaciones del Bosque Atlántico (CeIBA), Puerto Iguazú, Argentina, 4Instituto de Biología Subtropical (IBS), Puerto Iguazú, Argentina
Thursday 2:15-2:30, Ballroom B
Recent studies of intergroup aggression suggest that location-dependent dominance permits small groups to stably coexist with larger neighbors. Among Argentine tufted capuchin monkeys (Sapajus [Cebus apella] nigritus), however, the outcome of intergroup aggression is determined by relative male group size, suggesting that group extinctions and home range displacement should be more frequent. Here we investigate the consequences of intergroup aggression on subsequent use of contested areas for three capuchin monkey groups at Iguazú National Park. During all-day group follows, we recorded the location of the group’s center at 15-minute intervals. We used linear mixed models to examine the effect of intergroup encounters (N = 47) on intervals between revisitations to one hectare quadrats (N = 814 revisits), controlling for seasonal availability of fruit resources and relative intensity of use across seasons. In the absence of intergroup encounters, groups return more rapidly to areas with either high densities of seasonally-important fruit resources or intensive use throughout the year. Regardless of the quality of the area, intergroup encounters occurring in intensively-used areas do not affect return times; however, responses to encounters that occur in infrequently-visited portions of the range depend upon local resource availability. Both wins and losses in low-quality areas significantly increase revisitation intervals, whereas – in high-quality areas – patch return times decrease following an encounter. These results support a learning-based mechanism for home range maintenance, wherein territorial expansion by dominant groups is constrained by interaction costs imposed by subordinate groups that perisist in using familiar areas despite repeated defeats.
This study was funded by the American Society of Mammalogists, Consejo Nacional de Investigaciones Científicas y Técnicas, Idea Wild, the Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0752683), and the Wenner-Gren Foundation (7929).