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

van Leeuwen, Edwin J.C.; Staes, Nicky; Brooker, Jake S.; Kordon, Stephanie; Nolte, Suska; Clay, Zanna; Eens, Marcel; Stevens, Jeroen M.G.

Abstract

Bonobos are typically portrayed as more socially tolerant than chimpanzees, yet the current evidence supporting such a species-level categorization is equivocal. Here, we used validated group-level co-feeding assays to systematically test expressions of social tolerance in sixteen groups of zoo- and sanctuary-housed bonobos and chimpanzees. We found that co-feeding tolerance substantially overlaps between the species, thus precluding categorical inference at the species level. Instead, marked differences were observed between groups, with some bonobo communities exhibiting higher social tolerance than chimpanzee communities, and vice versa. Moreover, considerable intergroup variation was found within species living in the same environment, which attests to Pan’s behavioural flexibility. Lastly, chimpanzees showed more tolerance in male-skewed communities, whereas bonobos responded less pronounced to sex-ratio variation. We conclude that the pervasive dichotomy between the tolerant bonobo and the belligerent chimpanzee requires quantitative nuance, and that accurate phylogenetic tracing of (human) social behaviour warrants estimations of intraspecific group variation.

Citation

van Leeuwen, E. J., Staes, N., Brooker, J. S., Kordon, S., Nolte, S., Clay, Z., …Stevens, J. M. (2023). Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations. iScience, 26(12), Article 108528. https://doi.org/10.1016/j.isci.2023.108528

• Journal Article Type: Article
• Acceptance Date: Nov 20, 2023
• Online Publication Date: Nov 23, 2023
• Publication Date: Dec 15, 2023
• Deposit Date: Dec 4, 2023
• Publicly Available Date: Jan 15, 2024
• Journal: iScience
• Publisher: Cell Press
• Peer Reviewed: Peer Reviewed
• Volume: 26
• Issue: 12
• Article Number: 108528
• DOI: https://doi.org/10.1016/j.isci.2023.108528
• Public URL: https://durham-repository.worktribe.com/output/1965594