There are examples of homosexual tendancies amongst other species. It has been documented in rats, primates (other than humans), lambs and other species. My friend has two pet rats, they are both male. One of them LOVES to try and hump the other. The other likes female rats only because he starts screaming, lol. And no, I'm not joking.

As for necrophiliac tendencies, wow, that's just whack.