Many investigators may feel that studies involving group manipulations involving older animals are untenable, fearing that such manipulations may harm or over-stress aged subjects. The present study demonstrates the safety of a technique which not only introduced aged rhesus monkeys into two groups, but resulted in their attaining planned dominance rank positions in each of the groups: one set of 4 as the highest ranking and the other set of 4 as the lowest ranking. The manipulation also effected the social behavior of the old animals isolating the high ranking males from social activity in their group.