Abstract # 187:

Scheduled for Friday, June 21, 2013 07:00 PM-09:00 PM: Session 21 (SG Foyer ABC) Poster Presentation


CHANGES IN WESTERN LOWLAND GORILLA (GORILLA GORILLA GORILLA) GROUP COHESION FOLLOWING THE BIRTH OF A BABY

L. M. Kurtycz, M. A. Shender and S. R. Ross
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL 60614, USA
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     Changes in group composition can alter the behavior of social animals such as gorillas. Although gorilla births are presumed to affect group spacing patterns, there is relatively little data about how these events affect gorilla group cohesion. We investigated how members of a western lowland gorilla group (n=5) at Lincoln Park Zoo (Chicago, IL) spaced themselves prior to and after the birth of a baby, to investigate changes in group cohesion. Gorillas were housed in an indoor-outdoor enclosure in which access to the outdoors was permitted when temperatures exceeded 40 F. We recorded spatial locations of each group member using 30-minute group scans on tablet computers with an electronic map interface, as well as noting their access to outdoor areas. Data from the four months following the birth was compared to a control period corresponding to early pregnancy. We measured distances between all possible group dyads for each scan and subsequently calculated a mean distance between all group members. An ANOVA revealed that access to the outdoors had no effect on group spacing (F(1,56)=0.066, p=0.799). However, the presence of a baby resulted in a significant reduction in inter-individual distance (F(1,56)=23.988, p=0.000), decreasing inter-individual spacing by 12.5%. This information helps characterize the behavioral impact of a new birth on captive gorilla social structure and could potentially inform future management of breeding gorilla groups.