I am male.
Human to human relationships, I am technically heterosexual, the caveat being that I have engaged in activities with men, but with the permission and urging of the girls I was with at the time.
Human to animal relationships I would have to say that it would be homosexual, mainly because the one time I tried ti mate with one of our female horses (mares), I was too short to "do the deed." ( I tried getting on her back and sliding down her rump to get inside of her and her tail was not cooperating.)