Tokuda, K. & Jensen, G.D. Primates (1968) 9: 319. doi:10.1007/BF01730874
An established group of pigtailed monkeys (Macaca nemestrina) was evaluated for aggressive behavior. The four highest ranking members of the group were removed one-by-one. Aggression was higher during all periods when the leader was absent and it decreased when he was returned. The leader male of aM. nemestrina group plays the major role in the control of aggression within the group.