Primate group size and interpreting sociolecological models: Do folivores really play by different rules?

Because primates display such remarkable diversity, they are an ideal taxon within which to examine the evolutionary significance of group living and the ecological factors responsible for variation in social organization. However, as with any social vertebrate, the ecological determinants of primate social variability are not easily identified. Interspecific variation in group size and social organization results from the compromises required to accommodate the associative and dissociative forces of many factors, including predation,(1-3) conspecific harassment and infanticide,(4-6) foraging competition(1,7) and cooperation,(8) dominance interactions,(9) reproductive strategies, and socialization.(10-12) Causative explanations have emerged primarily through the construction of theoretical models that organize the observed variation in primate social organization and group size relative to measurable ecological variation.(1,2,13-16).