When dogs are sleeping, with twitching legs, muffled woofs, and a wagging tale, are they actually dreaming? If so, what are they dreaming about? Furthermore, what’s the point of them dreaming at all?
Through the power of scientific rigor and viral videos of dogs sleepwalking, let’s find out.
Unfortunately, there’s the issue of language barriers with dogs meaning we can’t simply lay them down on a psychoanalyst's leather couch and let them bare their soul to us. However, there are a few clues which allow us to make comparisons with the sleep and dreaming of other mammals.
Human dreaming mainly occurs during rapid eye movement (REM) sleep. Although you can also dream in non-REM sleep, the content of the dream is typically much more boring. REM sleep accounts for less than a quarter of your total night’s nap, experienced in multiple cycles of about 90 to 20 minutes throughout the night. It’s typically associated with more vivid dreams, rapid eye movements, muscle atonia, faster pulse, and increased breathing rate.
Our canine companions sleep considerably more than humans but do also experience REM sleep and have a similar structure of sleep cycles to humans. On the other hand, scientists believe that reptiles and fish don’t have the REM sleep cycles, so they probably do not dream (as you can tell by their cold, dead eyes).
During a 2001 study in the journal Neuron, scientists at MIT's Neuroscience Research Center recorded the brain activity of rats when they were sleeping and went about their day-to-day life as a lab rat walking through a maze. Essentially, they found that the rats displayed similar brain activity during REM sleep as they did when they were performing a previous task awake. This suggests they were simply “replaying” the memories of the task they just performed.