Male-Female, Female-Female, and Male-Male sexual behavior in the stumptail monkey, with special attention to the female orgasm
Mating behavior in Macaca arctoides has several features unique to the macaques. Observations of laboratory groups of stumptail monkeys revealed that their single-mount copulations are exceptionally long, that male orgasm is unusually salient (being characterized by body rigidity followed by body spasms and a characteristic facial expression and vocalization), and that the couple generally remains united, or “tied,” in a genital lock after ejaculation. This pattern behaviorally accentuates some of the physiological aspects of coitus. Consequently, they can be more easily observed than in any of the other macaques. Homosexual encounters were numerous. They always involved sexual inversions (that is, the assumption of the coital role generally assumed by the opposite sex). Orgasms were observed in females during homosexual interactions—they were easily distinguished by all the features enumerated above as characterizing masculine orgasms. Examination of the behavior of females during heterosexual coitus suggests that female orgasms also occur during heterosexual interactions. The female potential for orgasm and ability to assume inversed sex roles offer a new view of nonhuman primate sexuality. Females are evidently capable of taking active roles in coitus, and their potential for orgasm is much more similar to that of males than previously thought.