Research confirms what pretty much every dog owner knows: dogs dream when they sleep, just like people do. I can attest that my dog Tika, the golden retriever has a very active dream life. It appears that she runs, woofs, squeaks, wiggles, and eats while asleep.
Dogs have different phases of sleep, just like humans do. The only difference is in the length of time. Our sleep cycles tend to be longer, but like people, dogs go through slow wave sleep (SWS) and rapid eye movement (REM) sleep. All that dreaming happens in the REM sleep cycle.
When your dog is still and breathing deeply, he’s probably in the SWS sleep phase. Although he seems to be doing a great imitation of a rug, he’s actually much more likely to wake up during this sleep phase than during REM sleep. Once the dog starts "running" or twitching, he’s in the REM cycle, which is extremely deep sleep and when tests have shown there is the most brain activity.
Apparently a dog’s sleep position also indicates how they sleep. A dog curled up in a tight ball may look like he’s sleeping hard, but may not be. To enter the deepest REM sleep a dog has to be completely relaxed. But he can’t be completely relaxed when all his muscles are tensed to keep him curled up. So that compact hound may be more awake than you thought.
Along the same lines, a dog sleeping on his back with his feet in the air isn’t doing it just to be weird. Dogs have less fur on their tummies, so when they are hot, they tend to sleep upside-down, since it cools them off.
And here’s one I always suspected. Dogs who lie back to back are bonding with one another. When they lie with their back resting on you, they are bonding with you. This contact shows a desire to be with the other dog or human. It’s a way of showing affection.
Interestingly, puppies and old dogs dream more than middle aged dogs. So as your dog ages, you can expect more dream activity. This change also may be part of why older dogs may seem to be more irritable. Dogs that are awakened from deep REM sleep may respond in much the same way you do: grouchily. In fact, it’s important to instill in kids that old adage: "let sleeping dogs lie."
Statistically, 60 percent of dog bites happen to children and 70 percent of dog bites occur on the owner’s property. In other words, the family dog can and will bite the kid if the kid hasn’t been taught how to behave around the family pet. People always seem to think that their child or their dog "would never do that," but annually 4.7 million people in the US are bitten by dogs, so dog bites are hardly uncommon.
Although it’s fun to watch the antics of dreaming dogs, it’s best to let them dream their happy dreams of chasing squirrels uninterrupted.