Biological Exuberance: Animal Homosexuality and Natural Diversity

It should also be pointed out that something of a double standard exists regarding what is interpreted as “natural” as opposed to “captivity-induced” behavior. It is common zoological practice, for example, to study mate choice in pair-bonding species (such as birds) by setting up captive situations where individuals are only given a “choice” of opposite-sex partners. It is also standard practice to keep zoo animals strictly in heterosexual pairs for breeding purposes. Thus, a sizable portion of reported “heterosexual” behavior is in fact based on situations that would be considered “artificial” if they were used to study homosexual behavior. In other words, if animals are kept only with members of their own sex and then subsequently exhibit homosexual activity, this is overwhelmingly interpreted as “situational” behavior that would not otherwise happen. In contrast, if they are only given access to opposite-sex partners and subsequently exhibit heterosexual behavior, this is without exception interpreted as an expression of their “natural” tendencies. Although researchers readily regard homosexuality to be the result of external or artificial factors operating on otherwise heterosexual animals, no one has dared suggest that the reverse situation might also sometimes occur—that heterosexuality could be “forced” on otherwise homosexual (or largely same-sex-oriented) animals. In fact, zoos and other captive breeding programs offer countless reports of animals “failing” to breed in captivity for no apparent reason when placed with opposite-sex partners. Even after exhausting the long list of factors that could be involved, animal breeders uniformly overlook the possibility that some of these individuals may simply have a preference for same-sex activities and/or partners.

In the majority of species where homosexuality has only been observed in captive or semi-wild conditions, researchers have confirmed that other aspects of behavior or social organization in captivity—including sexual behaviors—are comparable to those of wild animals. In some instances, behaviors once considered to be “abnormal,” “artificial,” or “unusual” products of captivity have also been documented in the wild. For example, Botos frequently play with man-made objects in aquariums (carrying and manipulating rings, brushes, and so on) and also interact playfully with animals of other species kept in their tanks. Wild Botos have also been observed in similar behaviors, playing with sticks, logs, fruit pods, and even fishermen’s paddles, as well as with other species such as river turtles. Tool use and manufacture by Orang-utans had long been known from studies of captive and semi-wild animals, but until the behavior was documented in wild Orang-utans in 1993, it was considered typical only of “artificial” situations. One researcher, studying captive Savanna Baboons, asserted that “certain types of behavior such as copulation during pregnancy or lactation may be related to caged life, and not be the norm in natural populations,” yet later studies of wild populations revealed that these behaviors do in fact occur regularly. Likewise, until it was documented in the wild, cross-species herding behavior by male Thomson’s Gazelles was thought to be caused by the unavailability of same-species groupings in captivity. Parenting trios, mate-switching, promiscuous copulations, and egg stealing were all initially observed in captive King Penguins and considered to be “unusual” (if not “abnormal”) behaviors. Yet detailed study of this species in the wild nearly thirty years later verified the occurrence of each one of these activities, as well as many other “unexpected” behavioral patterns. In a few cases, a more “unusual” behavior has only been documented in wild populations, or else is more prevalent in the field than in captivity: for example, reverse mounting in Black-headed Gulls and divorce in Flamingos.¹⁰³ Thus, while homosexuality has not yet been observed in many of these species in the wild, it is probably only a matter of time before it is.