Heterosexual experience and isosexual behavior in laboratory-housed male stump-tailed macaques (M. arctoides).

Three feral-born male stump-tailed macaques were housed together for 9 years from prepubertal age. The animals were then transferred to another laboratory and housed individually. They were pair-tested with each other (isosexual tests) and with females (heterosexual tests) for the first time in their adult lives. The study revealed that these males preferred females as sexual partners. They preferred each other as groom partner. The heterosexual experience did not drastically alter sociosexual behavior between the males.