Ironically, then, some of the most aggressive interactions surrounding variant sexualities/genders in animals involve heterosexual individuals being attacked, harassed, or invaded by homosexual, bisexual, and transgendered individuals. Nevertheless, the converse situation is not unknown: there are a number of examples of homosexual animals being targeted by heterosexual ones. All such cases involve a male interfering with homosexual activity between two females, often in an attempt to gain sexual access to one of the females. Male Brown Capuchins, Rufous Rat Kangaroos, and Sage Grouse occasionally try to break up mating activity between females, while male Gorillas have been known to attack two females that are having sex together. A male Bonobo repeatedly tried to interfere in the sexual activity between females by screaming, jumping, and sometimes even hitting them; rather than preventing their sexual interactions, however, this simply caused the females to have sex with each other furtively until he gave up harassing them, after which they could do so openly. Male Canada Geese and Wapiti sometimes try to separate female pairs and mate with one member by driving the other away or isolating her from her companion (the females usually do manage to get back together), while female Japanese and Rhesus Macaques in homosexual consortships are occasionally threatened and charged by males. Jackdaw females who are bonded to each other as part of a bisexual trio may be hindered in their joint parenting efforts by their male partner, who sometimes prevents one of the females from having access to their nest. In some cases, this may lead to a loss of eggs or young.35 Notably, these reaction patterns are not typical for most of these species, since on other occasions animals usually have no adverse response to same-sex activity (e.g., in Bonobos, Gorillas, Rufous Rat Kangaroos, and Sage Grouse). And rarely do these attempts at interference (even when violent) force individuals to permanently cease homosexual activities: rather, they simply alter their patterns of relating or resume their activities once the interference has stopped.
In contrast, there is a consistent pattern among White-tailed Deer of highly aggressive attacks against the transgendered “velvet-horns” (individuals who combine both male and female characteristics). These animals are continually hounded by nontransgendered Deer of all ages and sexes, who drive them away and prevent them from approaching feeding grounds. Sometimes a “gang” of up to half a dozen bucks will attack a velvet-horn, charging, chasing, and severely wounding it with their antlers. Possibly as a result of this social ostracism, velvet-horns tend to associate only with other velvet-horns, forming their own groups and generally avoiding other Deer.36 Other than this example, though, it is rare to find animals with different sexualities or genders living separately because of persecution from members of their own species.
In many cases, animals that are involved in homosexual interactions do live in segregated groups, but their spatial and social separation from other individuals is based on factors other than their sexuality (since such groups typically also contain individuals who do not engage in homosexuality). Among such factors are age, sex, breeding status, social rank, activity patterns, and various combinations of these. For example, homosexual activity is characteristic of groups of younger, nonbreeding, and/or lower-ranking Northern Elephant Seals; of nonbreeding males in the sex-segregated “bachelor herds” characteristic of many hoofed and marine mammals; of groups of Cliff Swallows engaged in mud-gathering activities away from the nesting colonies; of older, solitary African Elephant males; of nonbreeding Pied Kingfishers who are not involved in helping heterosexual pairs; and of groups of male Gray Seals who gather together during the molting season. Physical disabilities can also isolate individuals into their own groups: in Greenshanks, for instance, flocks of one-legged birds have been observed socializing and migrating separately from other individuals. This is probably because they are unable to keep up with other birds rather than because of social ostracism, since two-legged birds are also sometimes found in such flocks.37 In contrast, although some Greenshanks participate in homosexual activity, no corresponding “flocks” of clearly homosexual or bisexual birds are known in this species.
Still other factors besides hostility from other animals may be involved in the occasional segregation of individuals that participate in homosexual activity. Among Ring-billed Gulls, for instance, female pairs are sometimes relegated to poorer-quality nesting sites or smaller territories, or they end up congregated together in the spaces between territories belonging to heterosexual pairs. Although this could be due to active hostility from neighboring birds, it is just as likely due to the fact that female pairs are generally not as aggressive as male-female pairs and consequently are unable to defend their nest sites from the encroachments that all pairs must endure in crowded colonies. In addition, heterosexual pairs of Ring-billed Gulls that are younger or less experienced also tend to end up in suboptimal locations, and in some colonies female pairs are fully integrated or randomly distributed rather than being peripheralized or clustered. This indicates that hostility toward female pairs is not ubiquitous and, if present at all, is not directed exclusively toward female pairs. In some species segregation is actively initiated by the individuals who are involved in homosexual activity. Female Japanese Macaques in homosexual consortships, for instance, isolate themselves physically and socially from other troop members, including their relatives, to spend time together. Likewise, Black Swan male pairs may end up physically separated from other individuals, but this is because their territories are the most expansive and also because they are aggressive toward other birds that approach them. Greylag gander pairs tend to occupy a peripheral position in their flocks, but it is unlikely that they have been “forced” to the edges, since male pairs are typically more domineering than any other birds in the flock. Some scientists have suggested that such homosexual pairs may actually be performing the role of “sentinels” or guards for the group as a whole, hence their position at the flock’s “border.” There is also evidence that homosexual Mallard Ducks prefer each other’s company and tend to congregate together: when large numbers of male pairs were brought together in captivity, for instance, they tended to form their own flocks and socialize with each other rather than with heterosexual birds. The reason such flocks are not often seen in the wild, then, may simply be a matter of numbers. Because same-sex pairs tend to make up a minority of the population in this species, it is unlikely that enough homosexual individuals would ever be present together in a wild flock to form their own large groups.38