do pets dream? dr. kim smyth on what happens when the lights go out
For pet owners, the issue of whether or not their pets dream is easily settled by observing their furry friend while sleeping. I think it is safe to say we all, at one time or another, have witnessed our cat or dog stalking and chasing imaginary prey while sleeping .
Researchers have confirmed what pet owners have known to be true for decades – our pets do, in fact, dream. While we will never know for sure what they dream about, we do know that because their brains are wired similarly to ours, their dreams probably act out events of the day, much like ours do. A study done in 2001 took a look at the brain activity of rats as they ran through a maze and then again later while they were sleeping. The results were remarkably similar, suggesting that the rats were replaying their maze running experiences in their dreams. Fascinating!
Just like humans, dogs and cats go through alternating phases of brain activity while sleeping. The first stage of sleep is characterized by low frequency electrical activity in the brain and is called slow wave sleep. Slow wave sleep gives way to rapid eye movement (REM) sleep, characterized by higher frequency electrical activity and, as its name suggests, rapid eye movement.
Slow wave sleep alternates with REM sleep in 20 minute cycles in our pets, and it’s during REM sleep that pets may display the telltale signs of dreaming. For some dogs, it shows up as limb paddling, and we can easily imagine them chasing a rabbit or fox through a field. Some dogs whimper or produce stifled barks—maybe they are dreaming of a particularly fun romp with a friend. My dog used to curl her lips to show all of her teeth, protecting me from some dreamland prowler, I’m sure.
Cats, too, dream when they are in REM sleep. I’ve often heard my cat “chirping” at dream birds and twitching his whiskers in his sleep. Cats occasionally vocalize, too, and we are only left to wonder what they are saying and to whom they are saying it. While pets are dreaming, you may notice changes in their breathing, too, ranging from short rapid breaths, to exaggerated deep breaths as they replay the events of their day.
Pets can suffer from REM sleep disorders similar to humans, in which the brain center that turns off movement during REM is dysfunctional. These pets have abnormally excessive and sometimes violent movements while dreaming. Pets with this disorder swipe at their dream prey and sometimes launch themselves from their sleeping position to catch it. Obviously, this kind of behavior is unsafe for pets who may suffer injury when they fall off the bed or couch. It’s also unsafe for unsuspecting owners, who may become an unintended target if sitting too close. Medications may lessen the signs, but having these pets sleep in a padded crate is wise.
While it doesn’t take a scientist’s word to convince us that our pets dream, it is nice to know that we’re all in agreement. I, for one, would love a glimpse into our pet’s dream worlds, but I guess I’ll just have to settle for my own interpretations of their twitches and growls.