Preliminary observations on habitat, support use and diet in two non-native primates in an urban Atlantic forest fragment: The capuchin monkey (Cebus sp.) and the common marmoset (Callithrix jacchus) in the Tijuca forest, Rio de Janeiro

Space is an important dimension of the ecological niche. Differentiation in the use of vertical strata of the forest is related to species body size, and explains in part species coexistence at a local scale. Large neotropical primates dwell in the canopy, moving quadrupedally on large branches, whereas smaller species leap between narrow branches in the understory. We tested this general pattern by observing focal individuals of the capuchin monkey (Cebus sp.) and the common marmoset (Callithrix jacchus), both non-native species, living in a forest fragment within the Rio de Janeiro city. Results were in accordance with the pattern for neotropical primates. Vertical use of the forest seems to be related with ecological interactions, especially for C. jacchus restricted to the lower strata due to aerial predation. Preliminary observations on diet corroborate the omnivory of Cebus and the gum feeding characteristic of C. jacchus. For Cebus sp. the exotic jack-fruit (Artocarpus heterophyllus) was the most important food item. Predation of both primates on vertebrates, especially by C. jacchus on passerines, could cause an uncommon impact on prey populations. In spite of anthropogenic impact, these non-native primates maintain the general pattern of habitat, support use and diet of the same or similar species in native neotropical communities.