AGGRESSIVE INTERACTIONS OF CAPTIVE CHIMPANZEES LIVING IN A SEMI-FREE-RANGING ENVIRONMENT.
CALIFORNIA UNIV LOS ANGELES
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Captive chimpanzees living in a 30-acre desert environment were observed for 2-12 months during the summer of 1967. Postures, gestures, facial expressions, and to some degree vocalizations, as related to threat, attack, submission, and appeasement were identified and are described in this paper. The occurrence of protection and the use of sticks and rocks is also discussed. A preliminary study was conducted to determine the frequency of aggression and which animals were most often aggressors andor victims of attack. It was found that threatening and attacking animals generally have a closed, tight-lipped mouth or open mouth with teeth but not gums showing. Brows are down, eyes are wide open, the body is stiff and straight, and vocalizations are frequently absent. In contrast, victims usually have the corners of the mouth drawn back exposing teeth and gums, have brows up, vocalize frequently, and assume a body posture which is crouched and low to the ground. The preliminary study revealed that aggression appears to be much more common in this captive situation than in the natural habitat. Author
- Anatomy and Physiology