An ecological study of the pygmy chimpanzees (Pan paniscus) of Yalosidi,Republic of Zaire

The pygmy chimpanzees of Yalosidi, near the southeastern limit of the range of this species, differ in group size, food habit, nesting behavior, response to humans, etc., from those of other localities (Wamba, Lomako, and Lake Tumba). It is inferred that the pygmy chimpanzee has a wide range of ecological variation. A comprehensive use of the habitat was characteristic of the Yalosidi pygmy chimpanzees. Every stratum of every vegetation type in their habitat was used by them for feeding, resting, or sleeping. The wide ecological niche of pygmy chimpanzees probably permits their survival in competition with other nonhuman primates of Yalosidi, which are more agile but confined to more limited niches.