Lacassagne has also noted among young fowls and puppies, etc., that, before ever having had relations with the opposite sex, and while in complete liberty, they make hesitating attempts at intercourse with their own sex.[5] This, indeed, together with similar perversions, may often be observed, especially in puppies, who afterward become perfectly normal.

Among white rats, which are very sexual animals, Steinach found that, when deprived of females, the males practise homosexuality, though only with males with whom they have long associated; the weaker rats play the passive part.

But when a female is introduced they immediately turn to her; although they are occasionally altogether indifferent to sex, they never actually prefer their own sex.[6] With regard to the playing of the female part by the weaker rats it is interesting to observe that Fere found among insects that the passive part in homosexual relations is favored by fatigue; among cockchafers it was the male just separated from the female who would take the passive part (on the rare occasions when homosexual relations occurred) with a fresh male.[7] Homosexuality appears to be specially common among birds.

It was among birds that it attracted the attention of the ancients, and numerous interesting observations have been made in more recent times.

Thus Selous, a careful bird-watcher, finds that the ruff, the male of the _Machetes pugnax_, suffers from sexual repression owing to the coyness of the female (the reeve), and consequently the males often resort to homosexual intercourse.