Kittens, like our babies, need a lot of sleep to help them grow. Their daily routine consists predominantly of sleeping, and when they’re not sleeping, they’re probably feeding. When kittens cry after waking up, it usually means that their bellies are empty and it’s time for nursing, so I imagine that the Munchkin kitten in this video definitely has a full belly because she’s not waking up for anything!
Once they have grown into adult kitties they still have a the ability to sleep a lot, anything between 13 to 18 hours a day and they manage to fall asleep anywhere! Oh to be a cat!