Does your dog twitch and bark softly when she snoozes? These seemingly random movements and vocalizations are perfectly normal, and experts argue that they're proof of the fact that dogs do dream when they're deep in sleep.
REM Sleep, Dogs and Dreams
Mammals all sleep, and as far as scientists can tell, they all also experience the state of deep rest known as REM sleep. It's during this part of the sleep cycle that dreams tend to occur, and that's when your pooch is most likely to vocalize and act out during naptime. In fact, REM stands for rapid eye movement, and if you look at your dog's face while he's fast asleep and barking or flailing his paws, you'll most likely be able to see his eyes darting around underneath his lids. The frenetic movement can seem eerie, but it's perfectly normal. It's actually a sign that your dog is dreaming while he gets much-needed deep sleep.
Researchers from respected institutions like Harvard and MIT have been studying animal dreams for decades, and in fact, animal behavior scientists have been studying dreams in lab rats, cats, and other mammals since the mid-1900s. In one of the more controversial sleep experiments known to pet science, the French researcher Michel Jouvet altered the brains of cats in his lab to allow for full movement during sleep. These cats acted out hunting behaviors on phantom dream rats, pouncing, chasing, and batting at unseen foes while fully asleep. Subsequent studies on animals like rats revealed brain wave patterns that are similar to those seen in humans during sleep, and in fact, these experiments showed that rats might even be recalling memories from their day while they sleep.
Human Dreams vs. Dog Dreams
There's one recurring theme in the discussion of dog dreams: statements like "there's no reason to assume animals are any different" paired with a comparison to human dreams. Because there's no way to read minds at this point, sleep researchers have to take a few logic-based leaps in their findings about animal dreams. Though researchers can't physically see what dogs and other intelligent mammals dream about, there's plenty of evidence to suggest that the brain acts similarly during REM sleep in all mammals.
Humans experience their own dreams firsthand, so similarities between our brain function and that of other mammals during REM sleep supports a logical conclusion that dogs do in fact dream. We can't necessarily tell exactly what dogs are dreaming about, though scientists, like Harvard's Dr. Dierdre Barrett, suggest that dogs' strong bonds with humans may mean they're dreaming about their favorite people while they snooze.