Although same-sex interactions involving genital contact have been reported in hundreds of animal species, they are routinely manifested in only a few, including humans. According to Bruce Bagemihl, same-sex behavior (comprising courtship, sexual, pair-bonding, and parental activities) has been documented in over 450 species of animals worldwide. Scientists perceive homosexual behavior in animals to different degrees. The sexual behavior of non-human animals takes many different forms, even within the same species, though homosexual behavior is best known from social species. Various forms of this are found in every major geographic region and every major animal group.
This may include same-sex sexual activity, courtship, affection, pair bonding, and parenting among same-sex animal pairs. Various non-human animal species exhibit behavior that can be interpreted as homosexual or bisexual.