April 21, 2010|By Keith Farquhar
Q: Last night, my dog, Mandy, was wailing and crying in her sleep for several minutes. I had to wake her up and comfort her. Is there scientific evidence that dogs dream? She’s done this a few times, so I’m curious about what the experts have to say about dogs dreaming.
A: Dreams are subjective experiences, and while we can’t get our canine companions to tell us whether or not they have them, there is good evidence to suggest they do.
In humans, dreams are directly linked to a part of the sleep cycle called REM (rapid eye movement) or active sleep. Changes in the electrical activity of the brain can be measured with an electroencephalogram (EEG) during this phase. People awakened while in this sleep pattern often recall very vivid experiences, while people awakened in other phases of EEG activity rarely recall any dreams.
The pattern of brain activity during REM sleep in humans is also found very consistently in dogs. Outward indications of dreaming in dogs can include “paddling” of the paws, twitching of the facial muscles, whining, growling and rapid movement of the eyes. Many people describe their dog’s motions as “chasing rabbits.” In some instances, owners have described their dogs as being aggressive, fearful or confused if awakened during this type of sleep behavior. Most of the time these events last less than one or two minutes, though the physical activity may be much shorter than the actual EEG changes.
On average, 25 percent of the sleep cycle in dogs is spent in REM sleep. I have seen my own dogs showing this type of behavior, and there is no doubt in my mind that they are dreaming. I can only hope they are dreams of chasing balls in the field and not of chewing up my shoes!
Keith Farquhar, D.V.M., Sonoma Humane Society, www.sonomahumane.org.