You may notice that whilst dogs are sleeping they can moan, whimper, growl and also involuntary body gestures such as twitching, tail wagging and lip licking. In fact if you watch your dog sleep, it sleeps in very much the same way we sleep. Evidence supports that yes, dogs dream.
Dogs are similar to people with regard to their sleep patterns and their brainwave activity. Experiments testing dog brainwave activity during sleep have been reproduced and measured by researchers using an electroencephalogram (EEG). As they first fall asleep dogs are in a ‘lighter’ sleep mode where their breathing is very regular and they can be easily awakened. Once they enter deep sleep they are more difficult to awaken and their brain wave activity is greatly increased. Like people, once in deep sleep they enter a stage where their breathing becomes more irregular and they have rapid eye movements (REM) where actual dreaming takes place.
This rapid eye movement stage has this name because behind their closed eyelids, the dog’s eyes are moving rapidly back and forth. Presumably, they are watching the images that they are dreaming about. It is during this stage where they may also make noises and body movements occur. Even if it seems like they are having a bad dream it is best not to wake a sleeping dog. Dogs, like people, need uninterrupted sleep for healthy mental activity.