Birds of a Feather

Abstract

It is a widely held assumption that animals in their natural environment do not engage in homosexual behaviour and that, when it occurs in captivity, it is an aberrant by-product of being kept in same-sex groups. However, recent scientific findings show that these beliefs are incorrect. A growing body of evidence has been quietly accumulating suggesting that homosexual behaviour occurs in a wide range of mammals, birds, reptiles, amphibians and fish. More than 450 species of animals worldwide are known to engage in homosexual activity. In fact, such is the current fascination with homosexual behaviour in animals that a museum exhibition in Oslo, Norway, has been "mounted" to bring the topic to public attention. In the main, though, it seems that homosexual behaviour has been underreported in the literature, ignored, dismissed or misinterpreted by scientists due to moral, religious or biological bias. When homosexual acts are described in the literature, they are often anecdotal in nature or passed off as being "abnormal", dysfunctional or maladaptive. Homosexual behaviour has often been concealed by more socially acceptable explanations, such as mistaken sexual identity, play, or practice for later heterosexual encounters. Much debate surrounds what types of behaviour constitute homosexual activity. This is not surprising since, in the context of human sexuality, the term "homosexual" is loaded with social and cultural significance. However, by defining homosexual behaviour in animals on the basis of observable motor patterns alone, we can refer conservatively to any interaction among individuals of the same sex (male-male or female-female) within a sexual context as "homosexual". Thus homosexual behaviour in animals may be defined as any behaviour related to mating in heterosexual situations but exhibited by individuals of the same sex towards each other. Homosexual courtship behaviour, for example, refers to behavioural patterns that may lead to mounting or copulation. Homosexual mounting or copulatory behaviour describes attempted and/or achieved intercourse. Our own research, recently published in Behavioral Ecology, has focused on homosexual activity in birds. We surveyed the literature and found over 80 species in which homosexual behaviour has been observed and reported in the wild.