@Dagger yeah and animals don't care about fighting dirty. they are fighting to survive and breed. That is why there are a couple species where the males try to bite each others balls off, which seems a lot worse then attacking a different species genitalia
@TrueGoddessReincarnation you won't necessarily bleed to death, but the skin around there is fairly thin which makes it another prime spot to attack to gain entrance to more vital meat. If some predator was able to kill a hippo the only places they'd really be able to start eating at is the tongue, eyes, and genital region, same thing for elephants. In fact I think there was at night vision video showing hyenas going at a freshly dead elephant or something like that