Snakes need to be kept warm, along with an area with higher temperatures to allow for proper digestion. Ken, I don't know if I agree with your idea of being a 'god' so to say. In nature, these snakes don't always have to find a body of water when they need to cool down, nor should they have to. I don't know about that.
Evidence? I'm not too sure about that, but go take a look at snakes in the wild. I will guarantee they do not live in an environment in which the temperature is the same everywhere. They are built to survive in nature, the way things are. You can't just go changing that and expect things to be fine.