Abstract # 910 Poster # 55:

Scheduled for Thursday, August 18, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

A Search for Probable Cause: Self-Wounding in a Zoo Chimpanzee (Pan troglodytes)

V. James-Aldridge1,2
1University of Texas - Pan American, Dept. of Psychology & Anthropology, Edinburg, TX 78541, USA, 2Gladys Porter Zoo
     The deep wounds that appeared on the arms of an adult male chimpanzee in early 2000, originally attributed to aggressive behavior by his female cagemate, were eventually found to be self-inflicted. When both a January 2001 radiograph and February 2003 cervical and cranial MRIs failed to suggest any structural or circulatory abnormalities, however, attention turned to possible behavioral causes. A series of behavioral studies, however, indicated that the subject’s self-wounding was not related to being indoors or outdoors or to production of “high arousal” behaviors, such as displaying, swaggering, and cage rattling, suggesting that episodes were not triggered by stress. Further, the subject’s biting behavior was not typical of compulsive SIB, in that it occurred only infrequently and resulted in serious wounding rather than the mock biting usually described in the literature. Having largely eliminated psychological bases for the behavior, we returned to searching for an orthopedic or neurological cause. A repeat MRI of the chimpanzee’s cervical spine revealed posterior disc herniations at C3-4 and C4-5, accompanied by central spinal stenosis. On June 1, 2004 local neurosurgeons performed a diskectomy and reduced the stenosis. No instances of self-biting have occurred since the surgery. Without behavioral evidence to the contrary, however, the earlier apparent lack of a physiological basis for the problem could have led to an inappropriate assumption of underlying psychological pathology with serious implications for the animal’s future.