I know I read online somewhere that male manatees have been seen performing fellatio on eachother. I'll see if I can find the site. It was accidental when I found it to begin with, so, I'm not sure if I can find it again. I'm pretty sure chimps can be homosexual, too. They're supposedly one of (if not the) only species besides humans that have sex in the missionary position, facing eachother. Crazy, interesting stuff.