One of my beagles is sound asleep on the floor behind me, and all of sudden, his tail starts wagging. Thump, thump, thump on the side of the wall....and he just keeps sleeping away!
What is he doing? Chasing squirrels in his sleep? Dreaming? Smiling in his sleep?
Sometimes, when my little beagle sleeps, her little front paws will move like she's running in her sleep. And she lets out the tiniest little "boofs" (teeny barks!)