Cats need between 12 and 16 hours of sleep per day, so with all that practice it's no great mystery why cats are experts in the sleep department. Take a look at this list compiled by Bored Panda for example. As you can see, there is literally no place and no position in which a cat cannot sleep. Sink? No problem. Shoe? You got it. In a box? Bring it on! In a wine glass? Sure!