Scientists perceive homosexual behavior in animals to different degrees. A 2019 paper states that same-sex sexual behavior has been observed in over 1,500 species.[4] 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.[5] The motivations for and implications of these behaviors are lensed through anthropocentric thinking; Bagemihl notes that any hypothesis is "necessarily an account of human interpretations of these phenomena".[6]: 2
One species in which exclusive homosexual orientation occurs is the domesticated sheep (Ovis aries).[7][8] "About 10% of rams (males), refuse to mate with ewes (females) but do readily mate with other rams."[8]
In October 2023, biologists reported studies of animals (over 1,500 different species) that found same-sex behavior (not necessarily related to human orientation) may help improve social stability by reducing conflict within the groups studied.[9][10]
^Braithwaite, L. W. (1981). "Ecological studies of the Black Swan III – Behaviour and social organization". Wildlife Research. 8. Canberra, Australia: CSIRO: 134–146. doi:10.1071/WR9810135.