Biological Exuberance: Animal Homosexuality and Natural Diversity

To specifically address the question of “pseudoheterosexual” roles, scientists studying homosexual pairing in Western Gulls made detailed observations regarding whether one partner is more “feminine” and the other more “masculine,” in terms of which courtship, sexual, and territorial behaviors they exhibit. They found that most females employ a mixture of typically male and typically female patterns, although pair-bonds vary in the extent to which there is role differentiation between the partners. In some pairs, one bird performs the majority of mounting and courtship feeding (typically “male” activities) and less “head-tossing” (a typically “female” courtship behavior). In others, there is less of a distinction between the two partners, while in still others the two females participate nearly equally in gendered behaviors. Overall, however, scientists found that both partners in homosexual pairs are more similar to heterosexual females than to males in terms of the amount of time they spend on their nesting territories and their aggressive responses to intruders.²⁶

Another pattern of gender mixing involves role-differentiated combinations, in which same-sex interactions are largely gendered or separated into “male” and “female” roles, yet each individual still combines elements of both to varying degrees. This is a crossing or intermixing of “masculine” and “feminine” traits—in the domains of sexual, courtship, or parenting and pair-bonding behaviors—set against an overall pattern of polarity between the two. For example, male couples in Hooded Warblers often divide up their parenting duties into typically male and female roles: one male builds the nest and incubates the eggs (“female” duties) while the other defends the territory and sings (“male” activities). Yet layered on top of this are more subtle meldings of gender roles: the more “feminine” partner may also engage in the typically male activity of singing (although with a distinctive song type), while the more “masculine” partner may also feed his mate during incubation (an activity rarely exhibited by either partner in heterosexual pairs).²⁷

Other examples related to pair-bonding and parenting activities abound. The “masculine” partner in some Canada Goose (and Chiloe Wigeon) lesbian couples still carries out the quintessentially female activities of egg laying, incubation, and nest-building (the latter usually done only by females in these species). One female in Orange-fronted Parakeet homosexual pairs typically performs the “male” activity of nest-tunnel excavation, yet both partners may initiate courtship feeding (characteristic of males in opposite-sex pairs). And in Mute Swan female pairs, one partner stands guard and defends the territory (like a male), yet both females lay eggs (and both build the nest, typical also of both partners in heterosexual pairs). Some Lovebirds in same-sex pairs are role-differentiated, while others engage in combinations of “male” and “female” courtship and sexual activities. In either case, though, if two females are involved, they both perform the typically “female” roles of nest-building, egg laying, and incubation, while neither of two paired males shows any interest in nest-building (which is not characteristic of either heterosexual role). Some “feminine” partners in Chaffinch lesbian couples also exhibit characteristically male behavioral patterns such as singing, while both partners in role-differentiated Jackdaw homosexual couples (or trios) preen each other—a behavior typical only of females in heterosexual pairs. Similar patterns are to be found where sexual and courtship activities are concerned as well. In Long-eared Hedgehog lesbian interactions, for example, one female may be more “malelike” in initiating and carrying out various courtship and sexual behaviors, yet both partners may perform characteristically “female” invitation postures or typically “male” mounting attempts. Likewise, in courtship interactions between male Victoria’s Riflebirds or Blue-backed Manakins, the more “femalelike” partner that is being courted often responds with his own distinctly male display patterns.²⁸