Homosexual behavior in a laboratory group of stumptail monkeys (Macaca arctoides): forms, contexts, and possible social functions.

Observations of stumptail monkeys revealed frequent prolonged, intensive genital stimulation between individuals of the same sex, both males and females, adults and infants. These homosexual interactions occurred in positive emotional contexts, were accompanied by positive emotional facial expressions, and often were evidently elictied by the observation of heterosexual behavior. Infants' first copulations were performed with adults of the same or opposite sex who actively aided them. This suggests that homosexual and heterosexual encounters function as training for adult sexual roles, and that homosexual behavior is a basic primate pattern not exclusive to man.