Chimpanzees have a more elaborate and diversified material culture than any other nonhuman primate. Their behavior varies across tropical Africa in a way that does not always correspond to ecology. For instance, only West African chimpanzees use stone and wooden hammers to crack nuts in a number of populations, despite the wide availability of hammers and appropriate nuts across the species’ range. An understanding of the extent of this behavioral diversity is crucial to help researchers understand the likely incipient traditions of our own earliest hominin ancestors.