I think dogs sleep more than cats and cats sleep a LOT! lol Probably best described as a dognap.
But, a dog can be sound asleep snoring and dreaming in lala land... if the doorbell rings or if the ice cream man, postman, UPS truck, FedEx truck, water meter reader goes by... guess who is up and yapping at the window.
It's amazing how dogs can quickly be 'on guard'. Once the 'emergency' is over, back to lala land. Until the next episode!