Reduction of mortality due to fighting in a colony of rhesus monkeys (Macaca mulatta).

Mortality resulting from fighting in a breeding colony of rhesus monkeys living in groups was an important management problem. An attempt was made to understand the causes of such fighting and reduce it. It was found that the cause of the fighting was the social disruption resulting from a breeding protocol which required the regular removal of pregnant animals from groups and introduction of nonpregnant females. The basic protocol was not changed; however, social disruption was minimized, and a reduction in mortality was accomplished through alteration of group formation procedures, pregnancy palpation procedures and group composition.