New tools suggest local variation in tool use by a montane community of the rare Nigeria-Cameroon chimpanzee, Pan troglodytes ellioti, in Nigeria.

Regional variations in tool use among chimpanzee subspecies and between populations within the same subspecies can often be explained by ecological constraints, although cultural variation also occurs. In this study we provide data on tool use by a small, recently isolated population of the endangered Nigeria-Cameroon chimpanzee Pan troglodytes ellioti, thus demonstrating regional variation in tool use in this rarely studied subspecies. We found that the Ngel Nyaki chimpanzee community has its own unique tool kit consisting of five different tool types. We describe a tool type that has rarely been observed (ant-digging stick) and a tool type that has never been recorded for this chimpanzee subspecies or in West Central Africa (food pound/grate stone). Our results suggest that there is fine- scale variation in tool use among geographically close communities of P. t. ellioti, and that these variations likely reflect both ecological constraints and cultural variation.