I am interested in what you have said re homosexuality in the animal kingdom. Can you link me to any sources that have documented this in a study?
I don't think anyone has studied homosexual behavior in animals, because the phenomenon is virtually non-existant. However, there are some observations of males mounting other males that may have been reported as an aside comment in published articles. I would begin with the work of Frank A. Beach with Beagles. There is a doctoral dissertation that uses feminized male rats (made that way by castration on day one of birth then given, in adulthood, ovarian hormones) who will behave like females in estrous (Robert K. Orndoff: 1975 or '76 in Dissertation Abstracts). Then there is the frequently reported mounting and pelvic thrusting behavior by estrous females directed to other females and males (see F.A. Beach) in rats, dogs and cows.
One more thing: There are many reports where the males and females are put together in groups and their sexual behavior observed. Although not the purpose of these studies, information regarding tendency to homosexual behavior can be derived by its absence. Again, Beach would be a good place to start.