Dog owners know that dogs dream, as evidenced by their occasional twitching and whimpering while asleep. Do cats dream? Most deﬁnitely. During deep sleep, a cat’s eyes move rapidly at times, even though the eyelids are shut.
The scientists refer to this as “rapid eye movement,” or REM, and deep sleep is often called REM sleep. While in REM sleep, cats may move their paws and claws, twitch their whiskers, change their posture and make sounds—in short, show that they are responding to something going on inside their heads, not outside.