Behavioral reactivity, dominance, and social functioning in male Rhesus macaques (Macaca mulatta)

Abstract

Few studies of individual differences in reactivity to social and nonsocial stimuli in nonhuman primates have adequately addressed the ramifications of these differences for dominance relationships. The present study used objectively-based measures of behavioral reactivity to examine individual differences in changes in dominance relations. Two cohorts of adolescent male rhesus macaques were tested for reactivity to a novel situation before (pretransfer) and after (posttransfer) they were permanently removed from their natal groups. Dominance relationships were monitored for the following 2 years. Dominance rank in the natal group was unrelated to reactivity measures. Pretransfer displacement activity was not correlated with pretransfer dominance but was correlated with posttransfer dominance risk. A composite score of three reactivity measures from both novelty tests was a poor predictor of dominance during the pretransfer and 1-year posttransfer periods, but was a good predictor of dominance at 2 years posttransfer. These results demonstrate a potential role for male rhesus macaques' dispositional characteristics in shaping the outcome of dominance interactions after males emigrate from their natal groups.