Diet and dietary-niche breadth of diurnal rain forest primates in the Central Western Ghats, India.

We studied the feeding ecology of 3 sympatric primate species, the lion-tailed macaque (Macaca silenus), bonnet macaque (Macaca radiata) and Hanuman langur (Semnopithecus entellus), in a tropical rain forest of the Central Western Ghats, India. Since the availability of leaves is much higher than that of fruits, we expected that the primarily folivorous langurs would use a larger number of resources than the primarily frugivorous macaques. Since fruits are a relatively total resource, unlike leaves, of which only selected parts are consumed, we expected that the primarily frugivorous macaques would use resources more proportionately than the folivorous langurs, resulting in a wider food niche breadth in macaques. We collected data on these primate species over a period of 2 years using scan sampling in a contiguous rain forest. We calculated Levin's standardised food niche breadth for each species. Langurs used a larger number of tree species than macaques, but their niche breadth was narrower than that of macaques. The majority of their diet (over 50%) came from only a few trees in the case of all three primate species. Long-term data are provided herein for the first time on the feeding ecology of bonnet macaques and Hanuman langurs in a tropical rain forest.