ENDOCRINE COORDINATION IN MONKEYS - MALE SEXUAL RESPONSES TO FEMALE

Free-ranging rhesus monkeys on island colonies near Puerto Rico breed with a distinct seasonal rhythm. Observations on adult monkeys in one such colony, La Parguera, during the non-breeding season showed that sexually quiescent male monkeys can be returned to a sexually active state by exposure to females artificially brought into estrus. Males responded both behaviorally by showing copulatory activities and by increased duration of grooming, and physiologically by showing evidence of increased testicular activity. Such behavioral and endocrine coordination points out: (1) the control hormones exert over primate sexual behavior, (2) that females communicate their endocrine state to males, and (3) the existence of a system for the synchronization of mating activities between the sexes, especially at the onset of the breeding season. © 1969.