Dog and cats dream
Dogs have been found to experience periods of REM (rapid eye movement) sleep. REM sleep in humans is associated with dreaming. Therefore, it is assumed that dogs dream. Similar to humans, dogs that are in REM sleep exhibit eyeball and lip movements, twitching of the extremities, and vocalizations.
Sleeping cats have been studied with electroencephalograms (EEG), which read their brain activity. Cats were found to be in REM sleep or deep sleep for 30 percent of their sleeping time. The REM sleep or deep sleep periods were accompanied by changes in body posture, paw and claw movements, whisker twitching, ear flicking, and, in some cases, vocalization. It is therefore assumed that cats dream or at least have semiconscious experiences that are similar to human dreams.