Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours. Some cats can sleep as much as 20 hours. While asleep, cats experience short periods of rapid eye movement sleep often accompanied by muscle twitches, which suggests they are dreaming. But what can a cat dream about? Maybe he dreams of becoming a fish so he can swim in the Ocean with other fish!