Social Behavior in Wild Male Chimpanzees: Development and Maternal Relationships

In social mammals, individual social strategies have been directly linked to fitness outcomes. Socioecological factors, such as dispersal patterns, can play a key role in shaping these individual social strategies. Because the majority of species with sex biased dispersal are female philopatric, there is a bias in the literature towards the importance of social bonds for female survival and reproductive success. However, much less is known about male philopatric species. Exploring social relationships and behavior in male philopatric species can help us shed light on how dispersal patterns influences social behaviors. In this dissertation, I use long-term data on wild chimpanzees (Pan troglodytes) from Gombe National Park to consider social behavior in a typically male philopatric species, focusing on the development of male and female social strategies and the mother-son relationship. In Chapter 2, I used 26 years of data on the chimpanzees of Gombe National Park to explore how male and female social behavior and partner preferences vary by sex. While I found no sex differences in the overall likelihood of socializing, males were more likely to play with immediate kin, non-immediate kin, and adult males, all of which may be important social partners for males later in life. In Chapter 3, I tested whether maternal gregariousness during her sons’ infancy related to his social behavior later in life. Here, I found that maternal gregariousness during early and late infancy was positively correlated with male gregariousness during the transition period (12-15yrs). Furthermore, while male gregariousness varied at a population level with age, individual levels of male gregariousness remained consistent across adulthood, suggesting that social exposure early in life can have lasting effects throughout adulthood. Finally, in Chapter 4, I tested the hypothesis that mothers benefit from having adult sons in their natal community. In accordance with kin selection theory, mothers biased their associations with their adult sons during anestrous periods, and particularly during the first two months postpartum, when infants are at the highest risk of injury from aggression. Future work will investigate if sons are more likely to intervene on behalf of their mothers and whether mothers without adult sons receive more aggression than mothers with adult sons. Taken together, these results increase our understanding of male social behavior and relationships in a male philopatric primate species and set the stage for future studies relating individual male strategies directly to fitness.

Author

• Wellens, Kaitlin Rose

Language

• en

Keyword

• Males
• Development
• Mother-son associations
• Chimpanzees
• Social Behavior

Date created

• 2018

Type of Work

• Dissertation

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Hominid Paleobiology

Degree

• Ph.D.

Advisor

• Murray, Carson M

Committee Member(s)

• Mann, Janet
• Fairbanks, Lynn A
• McFarlin, Shannon C
• Sherwood, Chet C

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/1z40kt11s