Animals engaging in homosexual behavior, from LiveScience.com. It’s long been a myth that homosexuality is a sentient choice of human beings alone.
Copulation could be used for alliance and protection among animals of the same sex. In situations when a species is mostly bisexual, homosexual relationships allow an animal to join a pack.
Petter Bockman of the University of Oslo‘s Natural History Museum:
“In bonobos for instance, strict heterosexual individuals would not be able to make friends in the flock and thus never be able to breed.”
Top ten animals with same sex behavior here.