Why do werewolves hate vampires?

They just do, no-one really knows why, I guess werewolves and vampies are just born enimes...apart from if lycans are involved. (Because they are half vampire-half werewolf...)
because werewolves think that vampires are going to suck their blood.

I have absolutely no idea, but there is a sort of repellent between the two. Just inborn or instinct I guess. Werewolves are just greedy anyhow; steal things from vampires