Abstract # 143:

Scheduled for Saturday, June 19, 2010 03:30 PM-03:40 PM: Session 25 (Medallion Ballroom A) Oral Presentation


BEHAVIORAL EFFECTS OF FEMALE IMMIGRATION ON SOLITARY AND BACHELOR GROUP MALE GORILLAS (GORILLA GORILLA GORILLA) IN CAPTIVITY

T. E. Fenn1,2, S. Ross3 and K. Wagner3
1Jacksonville Zoo and Gardens, 370 Zoo Parkway, Jacksonville, FL 32218, USA, 2Endangered Primate Foundation, 3Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo
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The introduction of new individuals to a great ape social group may exert significant behavioral effects on both the resident and emigrant apes. Monitoring behavior throughout the introduction process allows captive managers to address potential changes in animal welfare and in general informs the interaction between ape sociality and the captive experience. Per recommendation by the Gorilla Species Survival Plan, two female western lowland gorillas were physically introduced to a previously solitary male silverback and had visual and olfactory contact with a separate two-member bachelor group of gorillas, all housed at the Jacksonville Zoo and Gardens (Jacksonville, Florida).   During baseline, introduction and post-introduction phases, caretakers collected behavioral and proximity data using a handheld computer with focal animal sampling at 30-second intervals.  Preliminary results indicated that the previously solitary silverback expressed no change in behavior [F(20,72)=0.547, P=0.93] or proximity [F(6,86)=1.619, P=0.15] in response to the females arrival. However, the silverbacks in the separated bachelor group exhibited both behavioral and proximity effects associated with the post-introduction period, including decreased aggressive behavior [F(2,41)=8.48, P=0.001], and increased inactivity [F(2,41)=4.40, P=0.02] by one male, while both showed a progressive increase in inter-individual distance following the females’ arrival [F(2,85)=11.43, P<0.001].  Patterns suggest that management changes in a captive facility may extend beyond the immediate social group.  Further results will serve to inform decision making in captive gorilla management, specifically related to socialization and welfare.