Date of Award

Summer 7-29-2015

Degree Type


Degree Name

Master of Science in Integrative Biology (MSIB)



Major Professor

Jared P. Taglialatela, PhD

First Committee Member

Antonio Golubski, PhD

Second Committee Member

Troy Mutchler, PhD


Chimpanzees and gorillas are sympatric in most of their range in Central Africa, however, bonobos do not overlap with either of the other two species. This difference has been hypothesized to be the main factor leading to the socio-ecological traits of each species. Access to, and competition for, terrestrial herbaceous vegetation (THV) in each of the three species in thought to be linked to the social relationships and female-female bonds of each species. This study sought to provide a direct comparison of the social relationships of each of the three African Great Apes in captivity in order to elucidate similarities and differences in terms of their social tolerance. We hypothesized that bonobos and gorillas would both me more tolerant of conspecifics in close proximity across multiple behavioral contexts than chimpanzees. Our results did not support this hypothesis, in fact gorillas were the least tolerant of the three species whereas bonobos were the most tolerant. Theoretical modeling was also used to investigate the impact of changing environmental conditions on the behaviors of the three African Great Apes. Here, we hypothesized that high quality, clumped food would select for aggressive behaviors (characteristic of chimpanzees) and low quality, dispersed food would select for affiliative behaviors. Our results indicate that in these kinds of environmental conditions, these types of behaviors did emerge as stable. Moreover, environmental conditions mirroring those reported for gorillas and bonobos suggested the emergence of stable strategies that parallel social characteristics documented for those two species (such as gregariousness within groups).