Short-term consequences of intergroup aggression among tufted capuchin monkeys: implications for long-term coexistence among unevenly matched competitors

SCARRY, C. J.; TUJAGUE, M. P.

Congreso; Annual Meeting of the American Association of Physical Anthropologists; 2013

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 predicted primarily 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 all 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.