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van Leeuwen EJ, Staes N, Brooker JS, Kordon S, Nolte S, Clay Z, Eens M, Stevens JM. Group-specific expressions of co-feeding tolerance in bonobos and chimpanzees preclude dichotomous species generalizations. iScience 2023; 26:108528. [PMID: 38144453 PMCID: PMC10746535 DOI: 10.1016/j.isci.2023.108528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/21/2023] [Accepted: 11/20/2023] [Indexed: 12/26/2023] Open
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 behavioral 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 behavior warrants estimations of intraspecific group variation.
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Affiliation(s)
- Edwin J.C. van Leeuwen
- Animal Behaviour and Cognition, Department of Biology, Utrecht University, Padualaan 8, Utrecht 3584 CA, the Netherlands
- Behavioural Ecology and Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
- Centre for Research and Conservation, Royal Zoological Society of Antwerp, Koningin Astridplein 26, 2018 Antwerp, Belgium
- Department for Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Nicky Staes
- Behavioural Ecology and Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
- Centre for Research and Conservation, Royal Zoological Society of Antwerp, Koningin Astridplein 26, 2018 Antwerp, Belgium
| | - Jake S. Brooker
- Psychology Department, Durham University, South Road, Durham DH1 3LE, UK
| | - Stephanie Kordon
- Psychology Department, Durham University, South Road, Durham DH1 3LE, UK
| | - Suska Nolte
- Animal Behaviour and Cognition, Department of Biology, Utrecht University, Padualaan 8, Utrecht 3584 CA, the Netherlands
| | - Zanna Clay
- Psychology Department, Durham University, South Road, Durham DH1 3LE, UK
| | - Marcel Eens
- Behavioural Ecology and Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Jeroen M.G. Stevens
- Behavioural Ecology and Ecophysiology Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
- Centre for Research and Conservation, Royal Zoological Society of Antwerp, Koningin Astridplein 26, 2018 Antwerp, Belgium
- SALTO Agro- and Biotechnology, Odisee University College, Hospitaalstraat 23, 9100 Sint Niklaas, Belgium
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Bhattacharjee D, Cousin E, Pflüger LS, Massen JJ. Prosociality in a despotic society. iScience 2023; 26:106587. [PMID: 37124413 PMCID: PMC10134446 DOI: 10.1016/j.isci.2023.106587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/22/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
Prosociality is the intent to improve others' well-being. Existing hypotheses postulate that enhanced social tolerance and inter-individual dependence may facilitate prosocial preferences, which may favor the evolution of altruism. While most studies are restricted to "tolerant" (cooperatively breeding and self-domesticated) species, despotic societies provide an alternative opportunity to investigate prosociality due to nepotism and ample inter-individual dependencies. Japanese macaques live in hierarchical matrilineal societies, with strong kin bonds. Besides, tolerance among non-kin may persist through reciprocity. Using a group service food-provision paradigm, we found prosocial preferences in a semi free-ranging group of Japanese macaques. The extent of provisioning was at levels comparable to tolerant species. Dyadic tolerance predicted the likelihood and magnitude of provisioning, while kinship predicted the magnitude. We emphasize the role of a complex socio-ecology fostering individual prosocial tendencies through kinship and tolerance. These findings necessitate a framework including different forms of interdependence beyond the generally tolerant species.
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Affiliation(s)
- Debottam Bhattacharjee
- Animal Behavior & Cognition, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- Corresponding author
| | - Eythan Cousin
- Animal Behavior & Cognition, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- Department of Ecology, Physiology & Ethology, Faculty of Life Sciences, University of Strasbourg, 67000 Strasbourg, France
| | - Lena S. Pflüger
- Department of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
- Austrian Research Center for Primatology, Ossiach 16, 9570 Ossiach, Austria
| | - Jorg J.M. Massen
- Animal Behavior & Cognition, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- Austrian Research Center for Primatology, Ossiach 16, 9570 Ossiach, Austria
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