1. Lack of security: When cats are in a relatively unfamiliar environment or are frightened, they are prone to feeling insecure. The litter box, filled with the cat's own scent, makes them feel more at ease, so they choose to sleep in it. Pet owners can prepare a semi-enclosed cat bed for their cats and place some items with the cat's scent inside for them to sleep in. 
2. If your cat is urinating incontinent or constipated, and stays in the litter box for a long time without coming out, and frequently makes defecation postures, it may be urinating incontinent or constipated. Because it doesn't want to keep going back and forth to the litter box, the cat may sleep directly in the litter box. If you find that the litter balls in the litter box are getting smaller and smaller, or even often there are none, it is recommended to take your cat to the vet for a check-up.
