It is not known for certain whether dogs dream, as it is difficult to study the mental processes of animals. However, many scientists believe that dogs, like humans and other mammals, do experience a form of dreaming. This is based on the observation that dogs, like humans, go through rapid eye movement (REM) sleep, which is the stage of sleep when most dreaming occurs. During REM sleep, the brain becomes more active, and the muscles become relaxed, which is similar to what happens in humans during dreaming. While we cannot know for sure what a dog is dreaming about, it is likely that they experience something similar to a human dream.