Some of these animals have very violent "customs" when it comes to their rank in the animal society, who gets to mate with who, etc.

I think one of the most violent and uncomfortable "rituals" I've seen between two animals is when giraffes go at it.

I can't imagine the sheer force of impact that occurs when a giraffe uses that long neck as a handle and his/her head as a sledgehammer.

All I can say is that the cracking sound it makes on impact is absolutely nauseating.