ABSTRACT
The common pattern of niche differentiation based on size, diet, locomotion, social behavior, breeding systems, etc., in all primate communities is based on traits that evolved independently among different taxonomic groups, even as the rainforests differ. This is largely because they all inhabit the arboreal frugivorous adaptive zone. Phylogeny plays an important role in setting the foundational starting points of the radiations in morphology and behavior while also placing constraints on evolutionary potential. Two important regional examples of divergent patterns are the only terrestrial radiation of primates in Africa’s papionins, including baboons, and the predominance of specialized leaf-eaters among Asian Old World monkeys. Madagascar presents the most adaptive outliers because its climate and sparse crops of fleshy fruits lead to significant seasonal shortages. Asian fruits are predominantly wind-dispersed, without fleshy parts, and large fruit crops only occur in lengthy, years-long intervals, so most Asian primates are folivores. The Amazon has the richest, most diverse fruit supply and the most differentiated radiation of frugivorous primates. Fewer fruit and tree species occur in the more open African forests, making it conducive to below-canopy, semi-terrestrial omnivory and hard-fruit frugivory, a unique prelude to full terrestriality.
