Biological Exuberance: Animal Homosexuality and Natural Diversity

not identities (it was designed expressly to bypass the often problematic issue of people’s “self-identification”), and certainly no animal studies purport to assess anything as subjective as sexual “identity.” In its intended usage, though, the Kinsey scale (or a comparable measure of sexual gradations) in fact appears to be particularly apt for Bonobos. The figures cited above are based on the work of Dr. Gen’ichi Idani in Congo (Zaire), who studied a troop consisting of (coincidentally) exactly ten female Bonobos and tabulated all their homosexual genital rubbings versus heterosexual copulations over a three-month period. The percentages of homosexual activity in these individuals were 33, 36, 47, 68, 68, 70, 75, 75, 82, and 88 percent. Idani also tabulated the number of different male and female partners of each female (another possible measure of degree of bisexuality or behavioral “preference”). Again, the percentage of partners that were same-sex exhibits a range across all females: 36, 50, 50, 54, 67, 67, 67, 69, 71, and 80 percent. Clearly these individuals fall into a spectrum in terms of their sexual behavior and thus exhibit different degrees of bisexuality in terms of their sexual orientation (although none are in fact exclusively heterosexual or homosexual).²³

“Preference” for same-sex activity is, admittedly, a rather elusive concept to measure when dealing with nonhumans (though not nearly as slippery as “identity”). Although we cannot access their internal motivations or “desires,” animals do offer a number of other clues as to their individual “preferences” in addition to the proportion of their behaviors or partners that are same-sex. These include homosexual activity being performed in (spite of) the presence of members of the opposite sex, individuals actively competing for the attentions of same-sex partners (rather than “resorting” to such activity), advances of opposite-sex partners being ignored and/or refused, and “widowed” or “divorced” individuals continuing to pair with same-sex partners after the loss of a homosexual mate (even when opposite-sex partners are available). These types of behaviors have in fact been reported in more than 50 mammals and birds (see the profiles for some examples), indicating that for at least some individuals in these species, same-sex activity has “priority” over opposite-sex activity in some contexts. The converse is also true for species such as Canada Geese, Silver Gulls, Bicolored Antbirds, Jackdaws, and Galahs: in situations where opposite-sex partners are not available, only a fraction of the population engages in same-sex activity, indicating more of a heterosexual “preference” in the remainder of the population.²⁴ Animals who do participate in same-sex activity in such a situational context could perhaps be said to exhibit a “latent” bisexuality; i.e., a predominantly heterosexual orientation with the potential to relate homosexually under certain circumstances. Another factor to be considered when evaluating individual “preferences” or degrees of bisexuality is the consensuality of the sexual interaction. Female Canada Geese and Silver Gulls in homosexual pairs, for example, may engage in occasional heterosexual copulations under duress; i.e., they are sometimes forcibly mated or raped by males. Likewise, heterosexually paired males in Common Murres, Laysan Albatrosses, Cliff Swallows, and several Gull species may be forcibly mounted by other males. Technically, all such individuals are “bisexual” because they engage in both homosexual and heterosexual activity, but the sort of bisexuality they exhibit is far different from that of a female Bonobo or a male Walrus, for instance, who willingly mates with animals of both sexes.

Broad patterns of sexual orientation across individuals show almost as much variation as that within individuals. In some species, the majority of animals are exclusively heterosexual, but a small proportion engage in bisexual activities (e.g., Mule Deer) or exclusively homosexual activities (e.g., male Ostriches). In others, the vast majority of individuals are bisexual and few if any are exclusively heterosexual or homosexual (e.g., Bonobos). Other species combine a pattern of nearly universal bisexuality with some exclusive homosexuality (e.g., male Mountain Sheep). In still other cases, the proportions are more equally distributed, but still vary considerably. In Silver Gulls, for instance, 10 percent of females are exclusively homosexual during their lives, 11 percent are bisexual, and 79 percent are heterosexual. Homosexual-bisexual-heterosexual splits for specific populations of other species include: 22-15-63 percent for Black-headed Gulls; 9-56-35 percent for Japanese Macaques; and 44-11-44 percent for Galahs.²⁵

Thus, sexual orientation has multiple dimensions—social, behavioral, chronological, and individual—which must all be taken into account when assessing patterns of heterosexual and homosexual involvement. It is true that exclusive homosexuality in animals is less common than bisexuality—but it is not a uniquely human phenomenon, for it occurs in many more species than previously supposed. Moreover, because of the wide prevalence of bisexuality—both within and across species—exclusive heterosexuality is also certainly less than ubiquitous. Animals, like people, have complex life histories that involve a wide spectrum of sexual orientations, with many different degrees of participation in both same- and opposite-sex activities. To the question “Do animals engage in bisexuality or exclusive homosexuality?” we must therefore answer “both and neither.” There is no such thing as a single type of “bisexuality” nor a uniform pattern of “exclusive homosexuality.” Multiple shades of sexual orientation are found throughout the animal world—sometimes coexisting in the same species or even the same individual—forming part of a much larger spectrum of sexual variance.

Nonchalant Onlookers and Gay Ghettos: Social and Spatial Responses

While homosexual behavior is widespread among our primate relatives, aggression specifically directed toward individuals that engage in it appears to be a uniquely human invention.

—PAUL L. VASEY²⁶

An aspect of animal homosexuality that has received little attention in both popular and scientific discussions is the position or “status” of homosexual, bisexual, and transgendered individuals in the larger society. What kind of social response do they evoke from the animals around them? What is their spatial relation to the rest of the population—are they segregated, fully integrated, or somewhere in between? Primatologist Paul L. Vasey suggests that homosexual behavior in primates is characterized by a noticeable lack of hostility and segregation from the animals around them, and by and large this does appear to be true—not only for primates, but also for the vast majority of other species in which homosexual activity occurs. Almost without exception, animals with “different” sexualities and/or genders are completely integrated into the social fabric of the species, eliciting little of the attention, hostility, segregation, or secrecy that we are accustomed to associating with homosexuality in our society. Observer after scientific observer has commented on how homosexual behavior in animals is greeted with nonchalance from nearby animals. Individuals move effortlessly between their homosexual activities and other social interactions or behaviors without eliciting so much as a second glance from the animals around them.²⁷

Where individuals engaging in homosexual activity do attract attention, it is usually out of simple curiosity (e.g., African Buffalo, Musk-oxen), or else because other animals want to participate.²⁸ In a number of species such as Bonobos, Killer Whales, West Indian Manatees, Giraffes, Pronghorns, Common Murres, and Sage Grouse, homosexual interactions between two animals often develop into group sessions as more and more animals are drawn to the activity and join in. This is also true for heterosexual interactions in many of these species, and sometimes homosexual and heterosexual activity are part of the same group interaction. This illustrates an important point concerning the integration of homosexual activity within the larger social framework: when bisexuality is prevalent in a species, or when a large proportion of the population engages in homosexual activity (as is often the case), the distinction between “homosexual” and “heterosexual” animals melts away, as does the potential for aggressive responses based on those categories. An “observer” of homosexual activity could just as easily be a participant at some other time, and any separation between animals that engage in same-sex activity and those that don’t becomes essentially arbitrary.

Even in species where homosexuality, bisexuality, or transgender are not widespread, animals that participate in same-sex behaviors (or transgendered individuals) are not generally treated to adverse reactions from the majority around them. Rather, homosexual activity is regarded as routinely as heterosexual activity is. In fact, in many species it is heterosexual, not homosexual, behaviors that draw a negative response. In numerous primates and other animals, for example, male-female copulations are regularly harassed and interrupted by surrounding animals. Same-sex activity in these species is either disregarded altogether (e.g., Stumptail Macaques), or else is subject to a much lower rate of harassment and interruption than opposite-sex matings (e.g., Hanuman Langurs, Japanese Macaques).²⁹ Adult male Bonobos interfere with the heterosexual pursuits of younger males while ignoring (or even participating in) their homosexual activities, while heterosexual breeding pairs of Jackdaws, rather than same-sex pairs, are sometimes terrorized by nonbreeding heterosexual pairs (who may even kill their young). And in Guianan Cock-of-the-Rock, heterosexual courtship interactions are routinely interrupted and harassed by other males while homosexual activities are not. In fact, females defer to males engaging in same-sex courtship or copulation (by leaving or avoiding the display grounds while this activity is going on), and males may