One of my cats can't keep his head still. If he's sitting or standing still, his head will waver slightly. If he runs in circles, it gets much more noticeable as he gets dizzy. I'm pretty sure it's nothing serious and it's actually a lot better now than when he was a kitten - to the point that I don't even notice it most of the time, but the vet doesn't know what's wrong with him and I was just curious if anyone had any idea what this was. He's had his distemper and rabies shots.