Cats sleep for an average of about 15 hours per day, although kittens and older cats might sleep for as many as 20 hours a day. About two-thirds of their lives are spent asleep. They generally sleep for only short bursts of time, which is thought to be because they are natural predators and need to conserve energy for hunting while simultaneously being ready to pounce or run at the first sign of noise. Cats are genetically crepuscular, meaning that they are most active when light is low, such as at dawn and dusk. Those who live indoors are able to adjust their sleep cycles to sleep through the night like their owners. When cats are awake, they spend about one-third of their time grooming themselves.
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