Pacifying violent monkeys
But have you read about an experiment where they were placed with the calmer and more tolerant stumptail monkeys (M. arctoides). Being mixed with these calmer monkeys had a notable effect on the aggressive Rhesus monkeys, even after the calm stumptail monkeys were removed.
 Lindburg DG. (1971) "The rhesus monkey in north India : an ecological and behavioral study". In: Rosenblum LA, editor. Primate behavior: developments in field and laboratory research, Volume 2. New York : Academic Pr. pp 1-106.