Ranging, activity budget, and diet composition of red titi monkeys (Callicebus cupreus) in primary forest and forest edge

Deforestation and fragmentation of tropical rainforests are increasingly creating forest edges and corresponding edge effects. Furthermore, primary forest is increasingly being replaced by secondary forest. The presence of high population densities of titi monkeys in fragmented and secondary forests suggests that they are capable of adapting to such habitat alterations. The aim of our study was to examine the ability of the red titi monkey (Callicebus cupreus) to adapt to forest edges and secondary forest. We compared home-range use, activity budgets, and diet composition in two groups of monkeys: one in primary forest and the other in primary forest with a long edge bordering secondary forest. The latter group avoided the secondary forest and used the edge in proportion to its availability. Groups did not differ in activity budgets but did show slight differences in diet composition. Taken together, our results suggest that there are no major effects of forest edges and secondary forest on red titi monkeys; however, given the relatively short study period, generalizations should be avoided until more comparative data become available. Furthermore, the age or successional stage of the secondary forest must be taken into consideration when drawing conclusions about its suitability as a primate habitat.