Kinship, Dominance, and Social Organization in a Semi-Free Ranging Group of Ringtailed Lemurs (Lemur catta)

Investigators have demonstrated that kinship affinities greatly affect social relationships in a number of anthropoid species. Factors such as companion choice, proximity, mating patterns, and dominance ranks have been shown to be influenced by kinship. It has also been shown that dominance rank based solely on agonistic behavior is poorly correlated with ranks derived from alternative measures of social status, such as grooming received versus that performed, feeding priority, access to mates, and approach/withdrawal interactions. In this dissertation I report research that investigated the effects of kinship affinities on social behavior and which tested the traditional methods of assessing and arranging hierarchically agonistic dominance rank. The research was conducted on a semi-free ranging group of prosimian primates, the ringtailed lemur (Lemur catta) housed in a naturalistic forest habitat at the Duke University Primate Center, Durham, North Carolina. Observations were conducted for 24 months. Matrilineal kinship affinities strongly influence companion choice in mutual grooming, resting subgroup formation, play, and nearest neighbor preferences. Mating between adult kin occurs with less frequency than if matingpairs were formed randomly. Kin also tend to approach one another for all friendly behaviors more frequently than do nonkin or distantly related individuals. Agonistic dominance ranks show that females outrank males in all social contexts. Within each gender, however, traditional agonistic ranks correlate with alternative status measures for the alpha position primarily. Ranks are inconsistent among middle-ranking individuals. Male agonistic rank during the breeding season is not always correlated with access to estrous females. Yearly changes in dominance rank occur primarily in the breeding season for males. Female ranks change when infants are born and again when they are weaned. Females with higher collective matrilineal rank have a greater success rate in rearing infants to adulthood.The data presented in this dissertation fill a gap in the literature concerning the social behavior of lemurs and prosimians in general. The social organization of L. catta is strikingly similar to anthropoid species in terms of the effects of kinship affinities. Ringtailed lemurs differ markedly from anthropoid species due to consistent female dominance