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.
Other situations involving homosexuality in captive animals also occur. Often same-sex activity in one species has only been observed in captivity (e.g., Siamangs, Mute Swans, Sociable Weavers), yet a closely related animal does exhibit similar or identical behavior in the wild (e.g., White-handed Gibbons, Black Swans, and Gray-capped Social Weavers, respectively). In other cases, one form of homosexuality is seen in captivity and another form in the wild. In Griffon Vultures, for example, homosexual pairs and sexual activity have been observed in captivity while same-sex courtship and pair-bonding display flights have been seen in the wild. In Emus, sexual activity between males has been documented in captivity and male coparenting in the wild. In Galahs, homosexual pairs have been observed extensively in captivity but not in the wild, although “supernormal clutches”—nests with double the number of eggs, typical of female pairs in other birds—have been verified in the field. And in Cheetahs, same-sex courtship and sexual activity have been seen in captivity while male pair-bonds have been observed in both wild and captive animals. This suggests that the absence of certain behaviors in studies of wild animals are probably accidental “gaps” that will be filled once more extensive field studies are conducted. This is particularly likely when one considers that the proper observational techniques for identifying homosexual activity are often not employed, even in species where same-sex activity has previously been verified in captivity. In the most recent ongoing field studies of Griffon Vultures, for example, the sex of birds is determined “behaviorally” by their position during mounting (top bird = male, bottom bird = female), or not verified at all, thereby precluding the possibility of detecting homosexual pairs. “Behavioral” sexing has also been employed in the major long-running studies of large populations of wild King Penguins, Gentoo Penguins, and Flamingos—in some cases combined with “morphological” sexing, i.e., the larger bird in a pair is assumed to be male and the smaller female, without actual verification of sex—all species in which same-sex pairs have been observed in captivity but not yet documented in the wild. And the sex of wild Dugongs participating in mating behavior has never been unequivocally determined in nearly two decades of field observations; researchers invariably assume that the interactions are heterosexual, even though same-sex activity has been observed in captivity (and in the wild in the related West Indian Manatee).104
It must also be remembered that it is often extremely difficult to observe some species in the wild or obtain detailed information about their behavior. Many animals in which homosexuality has only been seen in captivity present formidable challenges to field study. Some are nocturnal (active only at night) or crepuscular (active at dusk or dawn), such as Lesser Bushbabies (and other Lemurs), Wolves, Rufous Bettongs, and Black-crowned Night Herons. Others are diurnal (active in the daytime) but engage in sexual behavior mostly at night (e.g., Red Deer). This can greatly hamper efforts to observe sexual activity: homosexual mounting in Red Foxes, for example, was only discovered by setting up remote-control infrared video cameras to continuously monitor nighttime activities in a captive population—virtually impossible to do under field conditions. Other species are highly elusive: Bush Dogs, for example, have rarely even been sighted in the wild, let alone studied, and the most complete analysis of their social organization in captivity was only published in 1996. Likewise, the elusiveness of Pig-tailed Macaques precluded detailed field observations until the early 1990s, while the first in-depth behavioral studies of wild Crested Black Macaques were published in 1997. Sometimes the inaccessibility of the animal’s habitat poses nearly insurmountable hurdles: Siamang Gibbons, for example, frequent the jungle canopy as much as 120 feet above the ground, and homosexuality in the closely related, and equally arboreal, White-handed Gibbon was not discovered in the wild until 1991. Whales and Dolphins spend less than 20 percent of their time at the surface of the water, and underwater observation (where sexual activity often occurs) is frequently impractical.105 This is compounded by the fact that recognition of individual animals and determination of their sex—essential for obtaining detailed behavioral data—is also usually extremely difficult. An animal’s size can also be a factor: few behavioral observations of wild Apereas have been made because they are so small and their social activities are often hidden in dense grass and brush. Small size (among other factors) also hampers field observations of Squirrel Monkeys, Rufous-naped Tamarins, and Rufous Bettongs. The latter species is also largely asocial or solitary, a problem encountered as well in Bears and numerous other carnivores, where many thousands of hours of observation in the field often yield precious little information about social or sexual interactions.