Comparisons of the catalogues of tool behaviors recorded at long-term chimpanzee study sites have shown that tool using repertoires differ between populations and even adjacent groups. The chimpanzees in the Goualougo Triangle have one of the largest and most complex tool repertoires reported from wild ape populations. Several behaviors considered universals among chimpanzees were confirmed in this population, but we have also identified new tool using behaviors and described behaviors that were previously known only from indirect evidence or limited observations. We reported the first observations of perforating termite nests, puncturing termite nests, and using leafy twigs as rain covers. We also reported a third tool set which is used in honey gathering. Discovery of the tool using behaviors of chimpanzees in the Goualougo Triangle not only enhances our knowledge of the central subspecies, but also expands the diversity of tool using skills known in this species.
The technological system of chimpanzees has been lauded as being the most sophisticated form of nonhuman material intelligence observed in natural environments. However, different tool behaviors of wild chimpanzees such as nut cracking and tool sets used in termite fishing have been referred to as “complex” without clearly defining which characteristics were sophisticated or indicating how these demonstrated advanced cognitive skills. To address these research questions, video recorded sequences of chimpanzee tool use were analyzed for element composition, structure, and hierarchical organization of object relations. Tool behaviors in the Goualougo Triangle ranged from simple tasks to hierarchical sequences, often involving tool manufacture and several tool modifications. In addition to showing that tool behaviors within this chimpanzee population varied in their degree of complexity, we found that these apes were capable of flexibly executing different tool using strategies and generalizing object relationships across different contexts. Flexibility in applying tool using skills across contexts demonstrates understanding of the dynamic relationships between objects. This raises the question of what specific factors could have shaped the broad and complex tool technology of chimpanzees and how these traditions are maintained.
The rich behavioral diversity and social inheritance system of wild chimpanzees has important, but often overlooked conservation value. In addition to changes in ape density or distribution, it is important to determine if human disturbances are affecting the traditional behaviors of wild apes. The conservation context of apes in the Congo Basin is rapidly changing with the advancement of mechanized logging and human settlement. The tool using traditions of wild chimpanzees are not likely to withstand the myriad of negative impacts that are often associated with the arrival of their modern human relations, which is why it is our responsibility not only to document but preserve remaining chimpanzee cultures.