The sleepiest animal in the world is the koala, who sleeps 22 hours a day.
Next is the sloth (20 hours), armadillo and opossum (tied at 19 hours each), lemur (16 hours), then hamster and squirrel (tied at 14 hours each).
How about cats? Though some cats can sleep up to 20 hours a day, the average cat sleeps 13 hours a day. In comparison to koalas, cats are downright energetic!