I'm convinced that they dream. I've seen too many human-like actions from sleeping dogs that I think were dreaming not to believe it.
Little yelps, moans, legs twitching, mouths moving, etc. I just don't see how they couldn't be dreaming.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf
An Unhappy German is a Sour Kraut!