Male homosexual mounting in the group-living feral cat (Felis catus)

Abstract

Male homosexual behaviour in the feral cat (Felis catus) living on a small island was investigated in order to test five possible hypotheses for male-male mounting; mistaken-identity, dominance-assertion, sexual play for practice, fighting, and outlet for sexual tension. During female estrus, 26 cases of male-male mounting by 14 male pairs were observed. No male homosexual behaviour was observed outside the estrous season. Males that mounted males (MM male) were heavier, older and more dominant, while males that were mounted (RM male) were lighter, younger and sexually immature. All MM males not only mounted males, but also copulated with receptive females during the estrous season. The sexual-play for practice hypothesis is not supported, since it is unlikely that practice for heterosexual copulation is necessary for elder and dominant males. The fighting hypothesis is also ruled out as an explanation, because young and sexually inactive RM males are unlikely to be serious competitors for heterosexual copulation. The three remaining explanations have strong supporting evidence, but dominance-assertion and mistaken-identity hypotheses also have counterevidence. It is concluded that the hypothesis of outlet for sexual tension is the most valid explanation for the male homosexual mounting observed in the population.