Biological Exuberance: Animal Homosexuality and Natural Diversity

Juveniles.” In D. M. Taub, ed., Primate Paternalism, pp. 113–26. New York: Van Nostrand Reinhold.

*Weiss, G., R. F. Weick, E. Knobil, S. R. Wolman, and F. Gorstein (1973) “An X-O Anomaly and Ovarian Dysgenesis in a Rhesus Monkey.” Folia Primatologica 19:24–7.

IDENTIFICATION: A medium-sized (2-foot-long) monkey with dark or reddish brown fur, a short, almost hairless tail, and mottled black-and-red skin on the face. DISTRIBUTION: Southeast Asia and south-central China; vulnerable. HABITAT: Dense forests, including mountainous regions. STUDY AREAS: Semiwild: island of Toto-gochillo, Lake Catemaco, Mexico; captivity: Stanford University; University of Helsinki; the Netherlands Primate Center; Yerkes and Wisconsin Regional Primate Research Centers; Calcutta and Paris Zoos.

Social Organization

Few field studies of Stumptail Macaques have been conducted, so little is known of their social organization in the wild. They generally appear to live in cosexual groups of 20–50 individuals with a matrilineal organization. The mating system is probably polygamous or promiscuous, involving copulations with multiple partners and little male parental involvement.

Description

Behavioral Expression: Male Stumptails form intense sexual “friendships” with each other, within which an extraordinary variety of homosexual activities are expressed. One male may develop strong affectionate bonds with another male, as shown by their embracing, gently nibbling at each other’s mouth, and huddling together. The two partners may even sleep together, one closely hugging the other from behind while holding his partner’s penis. The affection between these males is also expressed through sexual activity, ranging from mounting to oral sex to mutual masturbation. Mounting occurs in the typical front-to- back position found in heterosexual mating; pelvic thrusting, anal penetration, and occasionally ejaculation can all be components of this activity. Fellatio or oral-genital activity involves one male licking or sucking on the penis of the other for up to two minutes at a time. This is done in a variety of positions, for example with one male behind the other or mounted on him, sucking his genitals between his legs. The males may even perform mutual fellatio in a 69 position. Males also fondle one another’s scrotum and penis, rubbing the hand up and down the shaft; again, a number of positions are used—one male may stand sideways in front of another who is sitting down, spreading his thighs to allow the seated male to masturbate him, or they may engage in mutual masturbation by backing up toward each other and fondling each other’s genitals between their legs. Sometimes male Stumptails also sit together and masturbate themselves, stimulated by the sight of one another or of a nearby heterosexual mating. The partners in a sexual friendship may be of the same age, or one may be considerably younger than the other, perhaps even an infant.

Two male Stumptail Macaques in mutual fellatio

Female Stumptails also form sexual friendships with one another. These relationships, which involve a considerable amount of affectionate behavior as well, may be a stable association between just two females, or they may be more fluid, involving a network of three females, for example, or more short-lived pairings. Sexual behavior involves mounting with intense genital stimulation and orgasm. One female will climb onto the back of her favorite partner, using a position slightly different from heterosexual mating that allows her to rub her genitals against the rump of the other female. This may also be accomplished in a front-to-back sitting position, one female pulling the other up against her belly, and the two may even end up lying or leaning back together in this configuration. Lesbian interactions are prolonged, lasting up to two minutes (a duration similar to heterosexual mating), and the females usually make numerous pelvic thrusts comparable to the amount performed by a male in a heterosexual mounting. Orgasm is striking: the mounting female tenses up, first pausing and then showing a number of body spasms; her fur stands on end, and this is combined with a characteristic frowning and round- mouthed facial expression (also found in ejaculating males) and rapid breathing sounds. She also experiences a number of intense uterine contractions lasting for nearly a minute. The female being mounted does not, apparently, have the same sort of orgasmic response, although she is in a state of high sexual arousal, and will often reach back to clutch the mounting female and even kiss her during the climax. Following orgasm, the females usually hug one another and make teeth-chattering or squeaking sounds. In some cases females can apparently reach orgasm without direct genital stimulation, particularly when they are hugging their favorite female partner in great excitement after being reunited.

A female Stumptail Macaque kissing her female partner at the climax of mounting

Frequency: Homosexual activity is common in Stumptail Macaques, accounting for as much as 25–40 percent of all sexual encounters in some captive and semi-wild groups. In one study, nearly two-thirds of this same-sex activity was between females, while in another population, all same-sex mounting was between males.

Orientation: Most Stumptail females are probably simultaneously bisexual, interspersing heterosexual activity with homosexual activity. In fact, females have been known to participate in lesbian activities when they are lactating (and possibly even during pregnancy), indicating an easy compatibility between motherhood and homosexuality in this species. Some males show a decrease in the intensity of their same-sex friendships as they get older and may begin engaging in a larger proportion of heterosexual activity as they mature. Nevertheless, most males probably continue to have some homosexual contact throughout their lives.

Nonreproductive and Alternative Heterosexualities

Male Stumptails engage in both masturbation and nonreproductive heterosexual mating. In the latter case, males have been observed mounting females without full penetration, mating with menstruating females, rubbing their genitals on the female (sometimes to ejaculation), and even stimulating the penis with their own foot while mounted on the female. Both male and female orgasm can be a component of heterosexual mating. Sometimes, however, mating is distinctly less pleasurable—especially for the female, who may collapse under the weight of the male during copulation (he may be up to twice as heavy as she is). Females are also sometimes bitten by males during mounting, resulting in shallow cuts on her shoulders and upper arms (this occurs in about 15–18 percent of copulations). More than half of all matings involve male aggression (including chasing the female, pushing or pulling her, and fighting or biting her) and/or female resistance (including running away from the male, screaming, trying to dislodge him, and fighting with him). In addition, heterosexual copulations are often harassed by other individuals (of both sexes), sometimes in spectacular outbursts of activity that involve an entire social group. This often occurs following ejaculation while the two mating animals remain attached in a “copulatory tie,” similar to that of mating Dogs.

Sources

*asterisked references discuss homosexuality/transgender

*Bernstein, I. S. (1980) “Activity Patterns in a Stumptail Macaque Group (Macaca arctoides).” Folia Primatologica 33:20–45.

*Bertrand, M. (1969) The Behavioral Repertoire of the Stumptail Macaque: A Descriptive and Comparative Study. Bibliotheca Primatologica 11. Basel: S. Karger.

*Chevalier-Skolnikoff, S. (1976) “Homosexual Behavior in a Laboratory Group of Stumptail Monkeys