Biological Exuberance: Animal Homosexuality and Natural Diversity

Two male Gray Whales participating in homosexual activity off the coast of Vancouver Island. Only the erect penises of the whales are visible above the surface of the water, but this enabled scientists to verify the sex of the animals. Without this confirmation, observers would probably have mistaken this for heterosexual mating activity.

Moreover, many zoologists still routinely determine the sex of animals in the field based on their behavior during sexual activity—with the (often unstated) assumption that there must be both a male (the one doing the mounting) and a female (the one being mounted) in any such interaction. Of course, this automatically eliminates any “chance” of observing homosexual activity in the first place. A field study of Laughing Gulls, for example, utilized the following assumptions in determining the sex of birds: “(1) any bird copulating more than twice on top was presumed a male, and (2) the mate of a male was presumed to be a female.” Yet other studies of this species in both the wild and captivity have revealed that male homosexual mounting and pairing do in fact occur in Laughing Gulls. Scientists studying sexual behavior in Common Murres admitted that they probably underestimated the frequency of homosexual mounting because they assumed that sexual activity involved opposite-sex partners unless they had direct evidence to the contrary. Amazingly, this practice is even used in species where homosexual behavior is known to occur from previous studies of either captive or wild animals, such as Kittiwakes and Griffon Vultures.²⁸ True, some biologists have critiqued this method of sex determination—but only on the grounds that it can miss examples of reverse heterosexual mounting (where females mount males).²⁹ And in spite of its obvious shortcomings, behavioral sex determination continues to be employed in recent studies, some of which constitute the first and only documentation of little-known species. One can only guess at how many examples of homosexual activity have been and will continue to be overlooked because of this.³⁰

Even in captivity, the sex of animals is often mistaken, and the consequent “amending” of mating or courtship activity from heterosexual to homosexual sometimes results in elaborate retractions, revisions, and reinterpretations. Renowned German ornithologist Oskar Heinroth, for example, published one of the first descriptions of heterosexual mating in Emus—only to discover that the two birds he had been observing in captivity were in fact both males, prompting him to publish a “correction” to his earlier description three years later. In reviewing the earliest descriptions of courtship behavior in captive Regent Bowerbirds, scientists realized that what had previously been described as heterosexual activity was in fact display behavior performed between two males. This resulted in rather confusing citations of the earlier material such as the following, in which the true sex of the birds is indicated by the later author’s bracketed insertions (prefaced by the assertion “I make no apology for revising in brackets his text to make it meaningful”): “‘These love-parlours, each one built by a female [immature male] for her [his] sole use … were of the shape of a horseshoe … . The female would enter and squat in her [in the immature male’s] love-parlour, the tail remaining towards the entrance … the rejected females [immature males in adult female dress] … built or partly built three love-parlours in different spots.‘” The very first description of “heterosexual” courtship and mating in Dugongs (a marine mammal) was published, ironically, in a scientific article prefaced with lines of romantic verse about the “heaving bosoms” of mermaids and sea nymphs (creatures that the animal has historically been mistaken for). Ironic, because nearly a decade later biologists confirmed that both animals involved in this sexual activity were actually males.³¹