Dietary preferences of a submontane population of the rare Nigerian-Cameroon chimpanzee (Pan troglodytes ellioti) in Ngel Nyaki Forest Reserve, Nigeria.

We investigated the dietary preferences of chimpanzees residing in a Nigerian submontane forest using a combination of fecal analysis, observations of feeding remains, evidence from feeding tools and fruiting phenological data between April 2010 and March 2011. A total of 495 fecal samples were collected in which 52 fruit taxa were identified as having being consumed by chimpanzees, including 22 identified to species level and two identified to genus level. Ficus (seven species) was the most common seed genus identified, occurring in 61.2% of all fecal samples. Based on fecal analysis and phenological data, Ngel Nyaki chimpanzees do not solely consume fruits based on their availability within the habitat; while the proportion of fruit consumed did reflect the relative availability of fruit in the forest for some fruit species, Ficus was a preferred fruit even when scarce. In contrast, the proportion consumed of other fruit species was low relative to the abundance of their fruit available in the forest. Our results from the Rank Preference Index (RPI) suggest that relative preferences in fruit are seasonal. We discuss the role of Ficus in the diet of chimpanzees in Ngel Nyaki Forest Reserve.