Biological Exuberance: Animal Homosexuality and Natural Diversity

In “pseudoheterosexual” explanations of homosexuality, it is usually assumed that a same-sex interaction is initiated by the animal who is adopting behavior patterns of the opposite sex. That is, a sexual or courtship episode between males is triggered by one male performing typically female “invitations” to the other male, while an analogous interaction between females is initiated by one female making typically “male” advances toward the other. While the initiation of homosexual activities sometimes does follow this pattern, exactly the opposite is seen in as many—if not more—cases. Sexual activity between females is often initiated by the mountee making typically female solicitations or overtures toward another female—this is true for species as diverse as Lions, Squirrel Monkeys, Rhesus Macaques, Hanuman Langurs, and Sage Grouse. Conversely, it is also common for sexual interactions between males to be initiated by the mounter making a typically “male” approach to another male. Even in courtship activities, the “roles” of the participating animals often do not fall into the patterns predicted by a “pseudoheterosexual” interpretation. In Ostriches, for example, homosexual courtships are not prompted by “female” behavior on the part of a male, but rather are initiated by one male approaching another using behaviors unique to same-sex interactions. Similarly, male Musk Ducks perform their courtship displays without being “triggered” by female behaviors on the part of either males or females; rather, Ducks of both sexes are attracted to males who are already displaying.

A Greylag gander pair performing a synchronized duet of “rolling” calls. In this and other species, both males in a homosexual pair perform mutual or typically “male” activities rather than one bird adopting a “male” role and the other a “female” role.

Often only one animal in a same-sex interaction is classified by scientists as truly “homosexual”—the one engaging in the putative “gender-atypical” behaviors. Thus, a male animal that solicits and is mounted by another male is considered to be the “true” homosexual, while the male who mounts him is a “normal” heterosexual male who is reacting to “opposite-sex” mimicry. This kind of logic frequently leads to absurd and contradictory classifications of animals. We’ve already discussed cases of reciprocal mounting, where the exchange of “roles” between animals necessitates a corresponding switch in which one is considered to be engaging in “homosexual” behavior for the moment. Sometimes an animal is actually both mounter and mountee simultaneously: in Wolves, Laughing Gulls, Little Blue Herons, Sage Grouse, and other species, an animal mounting another individual (of the same or opposite sex) is sometimes itself mounted by an animal of the same sex. Thus, an individual can exhibit gender “typical” and “atypical” mounting behavior at the same time and can perform concurrent “homosexual” and “heterosexual” acts with same-sex partners. In other cases, these behaviors occur in the same individual but separated in time, and in ways that do not conform to a “pseudoheterosexual” interpretation. Typically, the “true” homosexual animal is thought to be limited to opposite-sex behavior patterns and hence incapable of actual heterosexual relations (e.g., a male playing the “female role” with a male partner is considered incapable of playing the “male role” with a female partner). However, bisexual animals who successfully mate and breed with opposite-sex partners often perform the “gender-atypical” role during their homosexual interactions, while strictly heterosexual animals may perform the “gender-atypical” role during their heterosexual interactions—showing that there is no necessary connection between homosexual and heterosexual “roles.”¹⁵