Cat Tails

I have observed dog tails in action - they more or less wag.


Cat tails are entirely different - they can do all sorts of things.  Tiger, the wonder cat, as he falls asleep, which he does often, the last 2 inches of his tail still wags up and down, while the main part doesn't move.


What the heck are in these things?  And where does the motor control come from?


I think I just scared myself.