Why is the natural enemy of the werewolf a vampire? Why not a werecat?

I had a wicked dream last night. I was being hunted in this massive library by a bunch of guys (all guys) from school, and they were WEREWOLVES.

I'm not sure exactly why they were hunting me, but the intent was to turn me into a werewolf.

I was running between the bookshelves when Apple of all people finally gets me. Haha, you know how vampires bite people's necks to suck their blood/change them? Apparently, werewolves do too!

Anyway. Apparently, the enemy of the werewolves were not vampires, but wereCATS. And I could be bitten by both and subsequentially turn into both, or else a strange combination of the two. If one of them bit the other IN MOST SITUATIONS, the other would die.

That's about when I woke up.

But I think that's pretty damn awesome.