Is it normal my cat is the boss of my dog?

I have a large cat (boy) and a smallish dog (girl). They grew up together, played together, and slept together. Now, ten years later, they hardly interact.

The cat always makes the dog move out of whatever warm spot she happens to be enjoying, just so that he can have the nice spot for himself. And the dog moves! Although, sometimes she does growl at him in protest if she's extra sleepy, but more often than not, she usually gives in and finds somewhere else to get comfy.

I discourage this whenever I see it, but it doesn't help. They don't fight, but the cat is obviously the boss. Is this normal? Anyone else out there with a dog/cat relationship story to share?