Have you seen your dog lying on a pillow? I heard that dogs like to hide their bodies but their faces to watch the surroundings. And the pillow is a useful object for supporting their heads. It’s an interesting theory. However, it still doesn’t explain why they sleep on it. I wonder if wild dogs or wolfs have access to something similar to pillows, would they use it? I think this kind of mysteries makes us anthropomorphize dogs. Sometimes when I look at Dingo’s face, I don’t see a dog but a baby.