It's true that you'll hear both sides. Some claim 'more aggressive', some claim 'no difference'. Others, like myself, share an opinion that they don't notice the snakes being more aggressive, but notice a better feeding response.

With one rat, I'd doubt you'd notice any difference. When you start increasing your numbers and they really start putting off a noticeable scent, then you'll be able to get a better idea.

When I first moved my rats in the same room as my snakes so many years ago, I thought that I'd at least notice a touch more cage aggression from the snakes, but so far, so good.

You need to get your little dude rat a buddy, by the way. They get lonely.