I think I've seen some of them eating. The other two, pain or sleep I'm not sure. It's a good theory though. Especially in this place, we really don't know how much technology they actually have and some of the stuff we do is pretty advanced and no one questions it.

[Like teleporting and pokeballs, etc.]

You'll like mystery books then. That's half the fun, trying to figure out the mystery as book goes along.