Abstract # 6113 Poster # 79:

Scheduled for Thursday, June 18, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


S. J. Hankerson, D. Glad and M. Kracht
University of St. Thomas, Department of Psychology, St. Paul, MN 55105, USA
     An overabundance of male gorillas in zoos has led to a push to house male gorillas in “bachelor” groups, a state rare in the wild. Researchers are concerned that these housing conditions may lead to high aggression, particularly while establishing dominance hierarchies, and may result in unstable long-term relationships. As a result of the genetic importance of these males, a viable, yet safe, housing option is essential for the long-term survival of the species. This project observed an established group of three male Western Lowland Gorillas, Gorilla gorilla gorilla, at the Como Park Zoo in St. Paul, MN. We examined behavior from 94.7 hours of data, collected March-August 2014. A total of 237 aggressive encounters were observed. The majority, 60.3% of these encounters involved displacement events or displays. Only 13.9% of encounters included hitting or biting, with the remainder comprising directed pursuits. Given the vast difference between indoor and outdoor conditions, we also compared aggression and activity budgets between these two locations. Randomization tests found no differences between locations for aggression rate (p = .950), or any of the aggression categories (p > .05). The bachelor group at the Como Zoo is relatively stable and non-aggressive. However, the three males included in this group are relatives (half-brothers and cousin). Future research should explore whether or not relatedness of individuals impacts relationship stability.