Biological Exuberance: Animal Homosexuality and Natural Diversity

In spite of apparently unabated popularity in scientific circles, a “pseudoheterosexuality” interpretation imposes a restrictive and often erroneous framework on animal homosexuality, and there are numerous arguments against it.¹⁰ To begin with, in an overwhelming number of cases homosexual behavior cannot possibly be construed as mimicking heterosexuality. In a number of species, unique sexual or courtship behaviors occur between animals of the same sex that are not found in heterosexual interactions. For example, homosexual but not heterosexual interactions in Bonobos, Gibbons, Stumptail Macaques, Crested Black Macaques, West Indian Manatees, and Gray Whales often involve mutual genital rubbing or manual and oral stimulation of the genitals.¹¹ The actions of both partners are often identical or reciprocal, and therefore neither animal can be construed as adopting a stereotypically “male” or “female” role.¹² In species such as Bottlenose Dolphins, Cheetahs, and Grizzly Bears (among others), same-sex pair-bonding occurs to the exclusion of opposite-sex pairing; thus, the “roles” of individuals in homosexual pairs cannot be modeled after male-female (heterosexual) “roles” because there simply are no such models in these species.

Even for animals where identical or similar behaviors occur in both homosexual and heterosexual interactions, the same-sex activities often do not fall neatly into the gendered patterns expected under a “pseudoheterosexual” interpretation. For example, homosexual mounting is often reciprocal, which means that the animals take turns in the mounter/mountee positions, with neither preferring exclusively “male” or “female” roles. Various forms of reciprocal mounting have been documented in at least 30 species (and probably occur in many more): simultaneous reciprocity, in which the partners exchange roles during the same mounting bout (as in Pukeko or Black-rumped Flamebacks); and sequential reciprocity, in which partners trade roles at different points in time—the latter can involve frequent alternation over an extended period as in Japanese Macaques, or perhaps a onetime switch as has been reported for some Bottlenose Dolphins. Moreover, in many species heterosexual mounting can be “reversed” or “inverted,” in that the female mounts her male partner. Thus, the “mounter” and “mountee” positions cannot be absolutely equated with fixed “male” and “female” roles even in opposite-sex interactions. Most “pseudoheterosexual” interpretations of homosexuality, therefore, involve stereotyped views not only of same-sex activity but also of male-female relations.¹³

Reciprocal, mutual, or non-“inverted” homosexual activities also characterize many other behavior categories besides mounting and sexual activity. In Laughing Gulls and Antbirds, for example, courtship feeding occurs in both heterosexual and homosexual contexts; between two males, however, this activity has a number of distinctive features owing to the fact that neither male is playing a “female” role. Males often engage in reciprocal courtship feeding by passing the food gift back and forth between them, and either partner may initiate the exchange (in heterosexual courtship feeding, typically the male initiates the activity and the female does not reciprocate). In a number of other bird species, including Greylag Geese, Mallard Ducks, Greenshanks, and Humboldt Penguins, both males in homosexual pairs exhibit typically male sexual, courtship, and pair-bonding behaviors, i.e., neither partner adopts a “feminine” role.¹⁴ Likewise, both females in homosexual pairs of Snow Geese, Mute Swans, Lovebirds, Red-backed Shrikes, and Blue Tits incubate eggs—an activity typical only for females in heterosexual pairs of these species—while both males in Emu and Greater Rhea same-sex associations incubate the eggs and raise the chicks (an activity performed only by males in heterosexual associations).

Male West Indian Manatees employ a wide variety of positions and forms of genital stimulation during their homosexual encounters, including manual, oral, and mutual genital contact. These are not characteristic of heterosexual interactions in this species and are a good example of homosexual behavior not being modeled on stereotypical “male” and “female” roles.