Abstract
Understanding intraspecific variation in sociality is essential for characterizing the flexibility and evolution of social systems, yet its study in nonhuman animals is rare. Here, we investigated whether chimpanzees exhibit population-level differences in sociality that cannot be easily explained by differences in genetics or ecology. We compared social proximity and grooming tendencies across four semiwild populations of chimpanzees living in the same ecological environment over three consecutive years, using both linear mixed models and social network analysis. Results indicated temporally stable, population-level differences in dyadic-level sociality. Moreover, group cohesion measures capturing network characteristics beyond dyadic interactions (clustering, modularity, and social differentiation) showed population-level differences consistent with the dyadic indices. Subsequently, we explored whether the observed intraspecific variation in sociality could be attributed to cultural processes by ruling out alternative sources of variation including the influences of ecology, genetics, and differences in population demographics. We conclude that substantial variation in social behavior exists across neighboring populations of chimpanzees and that this variation is in part shaped by cultural processes.
| Original language | English |
|---|---|
| Pages (from-to) | 11393-11400 |
| Number of pages | 8 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 115 |
| Issue number | 45 |
| DOIs | |
| Publication status | Published - 6 Nov 2018 |
| Externally published | Yes |
Bibliographical note
Funding Information:ACKNOWLEDGMENTS. We thank the Social Climate Coding Team led by Vivian Vreeman, including Maddalena Tacchetti, Karoline Kneist, Marjolein van Ginneken, Marloes van der Goot, Lisa-Marie Bossen, Clara Dubois, and Becky Koomen; Innocent Mulenga for facilitating the research; the Zambian research team, including Patrick Chambatu, Thomson Mbilishi, Albert Mulembo, Goodson Muletele, Felix Chinyama, Patrick Mwika, Mumba Kawele, Misheck Kasongo, John Kayuya, and Joseph Kasongo; the Zambia Wildlife Authority; the Chimfunshi Board of Trustees; and the Chimfunshi Research Advisory Board. E.J.C.v.L. was supported by the European Research Council (Grant Agreement 609819, project Constructing Social Minds: Coordination, Communication, and Cultural Transmission) and the Research Foundation Flanders (FWO).
Publisher Copyright:
© 2018 National Academy of Sciences. All rights reserved.
Funding
ACKNOWLEDGMENTS. We thank the Social Climate Coding Team led by Vivian Vreeman, including Maddalena Tacchetti, Karoline Kneist, Marjolein van Ginneken, Marloes van der Goot, Lisa-Marie Bossen, Clara Dubois, and Becky Koomen; Innocent Mulenga for facilitating the research; the Zambian research team, including Patrick Chambatu, Thomson Mbilishi, Albert Mulembo, Goodson Muletele, Felix Chinyama, Patrick Mwika, Mumba Kawele, Misheck Kasongo, John Kayuya, and Joseph Kasongo; the Zambia Wildlife Authority; the Chimfunshi Board of Trustees; and the Chimfunshi Research Advisory Board. E.J.C.v.L. was supported by the European Research Council (Grant Agreement 609819, project Constructing Social Minds: Coordination, Communication, and Cultural Transmission) and the Research Foundation Flanders (FWO).
Keywords
- Animal culture
- Behavioral diversity
- Chimpanzees
- Social learning
- Sociality