Effects of management methods, social organization, and physical space on primate behavior and health

The incidence of clinical treatment in a large colony of pigtailed macaques (Macaca, nemestrina) was studied retrospectively to assess the effectiveness of three sequential housing and management protocols. In the initial standard protocol, groups were housed in single rooms, with each room occupied by a different group after daily cleaning. In the experimental protocol, animals were housed in two-room suites dedicated exclusively to the resident group. This protocol was meant to reduce enteritis due to communication of Shigella flexneri across groups. Isolation of groups was coupled with the doubling of available space in an attempt to reduce stress. Under a final compromise protocol, a two-room suite was dedicated to each group, but the group occupied only one room at a time. The compromise protocol maximized isolation and reduced the available space to the level under the standard protocol. Thus, the study involved two main factors, the degree of group isolation and the amount and configuration of physical space available to each group. Under the experimental conditions enteritis increased, other communicable diseases did not decrease, and trauma from fighting increased by over 45% even though more space was available. Under the compromise conditions, trauma, enteritis, respiratory disorders, and inflammation all decreased markedly. Behavioral studies identified beneficial social behavior patterns associated with spatial reduction as the basis of the decrease in aggression, trauma, and disease under the compromise conditions.