Variation in cultural attitude, knowledge and individual motivational factors impact engagement and tool use in a field experiment in wild chimpanzees.

Cultural traditions shape how animals approach ecological problems. Over the last two decades, Ugandan chimpanzees (Pan troglodytes schweinfurthii) have engaged with the honey-trap experiment, an apparatus mimicking a beehive, while relying on their cultural knowledge. Here, we compared the behaviour of three Ugandan chimpanzee communities in the experiment, adding a previously untested community, the Mwera South chimpanzees of Bugoma Forest. First, we tested whether communities varied in their engagement with the experiment and investigated whether differences lay in individual or community-based characteristics. Second, we analysed individual variation within the same culture, particularly focusing on the new data coming from Bugoma Forest. We found that only the Kanyawara chimpanzees of Kibale Forest displayed a dedicated instrumental method, stick use, realized in their cultural knowledge and expressed by most members of the community, congruent with the largest engagement with the resource and suggestive of a general positive cultural attitude towards honey. By contrast, the two other communities appeared to lack a cultural attitude towards honey, with no attached tool technique overall. Nevertheless, there were also large inter-individual differences. Notably, Bugoma chimpanzees displayed undescribed behavioural flexibility, using a range of tool behaviours, including both stick and leaf tool use, a pattern never documented before. Cultural attitudes toward resources thus constitute an additional layer to culture in addition to instrumental knowledge and coexist with individual motivational traits in influencing the realization of cultural behaviour.