Our dog sleeps on her back from time to time. I think it works out like that because of her bed. She likes to be up against the sides of it, and apparently this is the best way for her to do it. When she was just a tiny puppy, she would sleep on her back everywhere. On her bed, on the top of the couch, on me, etc. She doesn’t do it as often now though, but I would say at least a couple nights a week.
She really likes it when we put her on her back between my wife and I on the bed, and pull the quilt up to her neck. I know, I know…
And, when they’re awake, petting. My little female corgi, Corky, loves this: She’ll flop on her back, look at you, and just wiggle until you bend over (or sit on the floor) and pet her. Then her little mind becomes an eggtimer: “Oooh pet me pet me I love the hand hand is good hand is good HAND MUST DIE! ATTACK!”
She doesn’t use the full force of her jaws because she’s just playing, of course, but suddenly having to play tug for one of your own appendages is a great way to increase your general awareness of the world and its inhabitants.
She most likes to sleep with her butt up against someone. Her head has teeth and her paws have claws, but her butt needs to be protected by a monkey. This can lead to a very small dog taking up 2/3rds of a reasonably large bed simply by forming a horizontal line from you to the other edge.
My dog would do this when sitting by the fire. He was a collie/shepherd mix and he’d lie on his back and sit by the fire and get roasting hot. Then again so would the cat but she wasn’t on her back.
My dog would also “sunbathe” like that in the sun during the summer. Maybe it’s a heat thing like maximizing warmth?
Simone the pit bull occasionally sleeps like that. I have cell phone pics of her sleeping on her back in a red sweater, but I would have to sign up for a pay service to download them (phone has no hardware port), so you’ll just have to imagine.
Her more typical sleeping position is the famous “pit ball.”
One of my PWDs sleeps on her back. Gotta’ admit it’s cuter to see it from stubby-legged breeds like the Corgi, though. Do Basset Hounds and Old English Bulldogs often sleep on their backs?
All my pets, from greyhounds to cats to rats, slept on their backs from time to time. The greyhounds mainly did it when sleeping on the couch- they used to back of the couch to support their position. Rats, especially, look dead when they sleep on their backs, with their little back feets sticking straight up in the air. My cat sometimes sleeps completely spread-eagled, which makes me have to come over and KISS KISS KISS his tummy.