Biological Exuberance: Animal Homosexuality and Natural Diversity

Considering the wide range of evidence against a dominance analysis of animal homosexuality—as well as a number of explicit statements by zoologists questioning or entirely discounting dominance as a factor in same-sex activities⁹⁵—it is surprising that this “explanation” keeps reappearing in the scientific literature whenever homosexual behavior is discussed. Yet reappear it does, even in several studies published in the 1990s. As recently as 1995, in fact, dominance was invoked in a discussion of mounting between male Zebras, and this explanation still has enough currency that scientists felt compelled to refute it in a 1994 account of homosexual copulation in Tree Swallows. In looking through the many examples of the way that this “explanation” has been used, it becomes apparent that the relevance of dominance is often asserted without any supporting evidence, then cited and re-cited in subsequent studies to create a chain of misconstrual, as it were, extending across many decades of scientific investigation. Again and again, early characterizations of homosexual activity as dominance behavior—often hastily proposed on the initial (and unexpected) discovery of this behavior in a species—have been refuted by later, more careful investigations of the phenomenon.⁹⁶ Yet frequently only the earlier studies are cited by researchers, perpetuating the myth that this is a valid characterization of the behavior. For example, in a 1974 report that described same-sex mounting in Whiptail Wallabies, a zoologist referred to dominance interpretations of Rhesus Macaque homosexuality even though more recent studies had invalidated—or at the very least, called into question—such an analysis for this species.⁹⁷

At times, the very word dominance itself becomes simply code for “homosexual mounting,” repeated mantralike until it finally loses what little meaning it had to begin with. “Dominance” interpretations have in fact been applied to same-sex mounting regardless of how overtly sexual it is. The relatively “perfunctory” mounts between female Tree Kangaroos or male Bonnet Macaques, as well as interactions involving direct clitoral stimulation to orgasm between female Rhesus Macaques, and full anal penetration and ejaculation in Giraffes, have all been categorized as nonsexual “dominance” activities at one time or another. Even though many scientists have gone on record against a dominance interpretation—thereby challenging the stronghold of this analytic framework—information that contradicts a dominance analysis is sometimes troublesomely discounted or omitted from studies. For example, in several reports on dominance in Bighorn rams, same-sex mounting and courtship activities (as well as certain aggressive interactions) were deliberately excluded from statistical calculations because they frequently involved “subordinates” acting as “dominants,” i.e., they did not conform to the dominance hierarchy. One scientist even classified some instances of same-sex mounting in Crested Black Macaques as “dysfunctional” because they failed to reflect the dominance system or exhibit any other “useful” properties.⁹⁸

Nor is this merely a question of relevance to scientists, or simply a matter of esoteric academic interpretation. The assertions made by zoologists about the “functions” of homosexual behavior are often picked up and repeated, unsubstantiated, in popular works on animals, becoming part of our “common knowledge” of these creatures. In a detailed survey of primate homosexuality published in 1995, zoologist and anthropologist Paul L. Vasey finally and definitively put the dominance interpretation of homosexuality in its proper perspective, stating that “while dominance is probably an important component of some primate homosexual behavior, it can only partially account for these complex interactions.”⁹⁹ We can only hope that his colleagues—and ultimately, those who convey the wonders of animal behavior to all of us—will take these words to heart once and for all.

The Desexing of Homosexual Behavior

… two males (Dinding and Durian) regularly mouthed the penis of the other on a reciprocal basis. This behavior, however, may be nutritively rather than sexually motivated.

—T. L. MAPLE, Orang-utan Behavior¹⁰⁰