Biological Exuberance: Animal Homosexuality and Natural Diversity

Wild animals often form significant pair-bonds with animals of the same sex. Homosexual pair-bonding takes many different forms, but two broad categories can be recognized: “partners,” who engage in sexual or courtship activities with each other, and “companions,” who are bonded to each other but do not necessarily engage in overt sexual activity with one another. More than a third of the mammals and birds in which homosexual activity occurs have at least one of these types of same-sex bonding. The archetypal example of a “partnership” is the mated pair: two individuals who are strongly bonded to one another in a way that is equivalent to heterosexually paired animals of the same species. Partners engage directly in courtship, sexual, and/or parenting behaviors; they usually spend a significant amount of time with each other; and they do similar activities together. This is found primarily in birds (more than 70 different species)—not surprisingly, since heterosexual pairing is typical of feathered creatures (but generally rare in other animal groups). Examples of homosexual mates are found in male Black Swans and Black-headed Gulls, and female Black-winged Stilts and Silver Gulls (among many others). In mammals, partnerships take many different forms, including “consortships” in female Rhesus and Japanese Macaques, “sexual friendships” in Stumptail and Crab-eating Macaques, “tending bonds” between male Bison, and “coalitions” between male Bonnet Macaques, Savanna Baboons, and Cheetahs. Some animals, while not necessarily forming same-sex bonds, do have “preferred” or “favorite” sexual and affectionate partners with whom they tend to interact more often than with others: this is true for Bonobos, Gorillas, Killer Whales, and Dwarf Cavies, among others.

A mated pair of female Canada Geese

Many forms of same-sex partnership are exclusive or monogamous, and partners may even actively defend their pair-bond against the intrusion of outside individuals (for instance in male Gorillas, female Japanese Macaques, and male Lions). Animals of the same sex sometimes also compete with each other for the attentions of homosexual partners, as in male Gorillas and Blue-winged Teals; female Orang-utans, Japanese Macaques, and Orange-fronted Parakeets may even compete with males for “preferred” female partners. Some partnerships, however, are “open” or nonmonogamous: female Bonobos and Rhesus Macaques, for instance, may have sexual relations with several different “favorite” partners or consorts (of both sexes). Males in homosexual pairs of Greylag Geese, Laughing Gulls, Humboldt Penguins, and Flamingos sometimes engage in “promiscuous” copulations with birds (male or female) other than their mate (heterosexual pairs in these species are also sometimes nonmonogamous). Another form of nonmonogamy occurs among lesbian pairs in a number of Gulls and other birds: one or both females sometimes mate with a male (while still maintaining their same-sex bond) and are thereby able to fertilize their eggs and become parents.

The second main type of homosexual pairing is the “companionship.” Two animals of the same sex may bond with each other, often spending most of their time together exclusive of the opposite sex, but they do not necessarily engage in recognizable courtship or sexual activities with each other. For example, older African Elephant bulls sometimes form long-lasting associations with a younger “attendant” male: these animals are loners, spending all their time with each other rather than with other Elephants, helping each other, and never engaging in heterosexual activity. Male Calfbird companions display and travel together and also sometimes share a “home” with one another (a special perch known as a retreat where they spend time away from the display court). Similar same-sex associations are found in many other species, including Orang-utans, Gray Whales, Grizzly Bears, Vampire Bats, and Superb Lyrebirds. Younger same-sex attendants are known as satellites in male Moose and shadows in male Walruses, while companions are called duos in male Hanuman Langurs and spinsters in female Warthogs—the latter is something of a misnomer, though, since Warthog companions do occasionally participate in sexual activity with males or females, but not necessarily with their companions.