Dietary variability in Cebus apella in extreme habitats: evidence for adaptability.

The dietary composition of Cebus apella in two subtropical forest environments of Argentina reflects the seasonal availability of potential food resources. In the marginal areas of the geographical distribution of this species, different resources are used during periods of scarcity. A greater tendency to use leaves in the diet is observed in the northwest (El Rey National Park), where there is greater seasonal variation of fruit availability. In El Rey, where there are few potential resources, the diet is dominated by a few resources, notably bromeliads. Where the resources are more abundant and the availability is more constant throughout the years (Baritú and Iguazú National Parks), the monkeys exhibit a feeding behavior similar to that seen in tropical areas. This ability of the genus Cebus to exploit resources not accessible to other primate species is one of the reasons for its wide geographical distribution and its widespread existence in ecosystems marginally used by primates.