Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations

The human species exhibits a remarkable level of social tolerance which has propelled a plethora of behavioural expressions pivotal to our biological success. To date, the evolutionary origins of humans’ “ultra-sociality” remain unclear, despite a substantial research focus on our closest living evolutionary relatives, the great apes. Bonobos are typically portrayed as more socially tolerant than chimpanzees and consequentially (sometimes) presented as a better model to study the evolutionary roots of human sociality. Yet, the current evidence supporting such a species-level categorization is equivocal. Here, we used validated group-level co-feeding tasks to test 16 independent Pan groups living in zoo (n=9) and sanctuary (n=7) settings, representing 225 individuals. We found that the expressions of social tolerance substantially overlapped between species, thus precluding categorical inference at the species level. Instead, marked differences were observed among groups, with some bonob..., ,