The Resident Rodent

I was at the computer. It was late and suddenly there was a commotion in the kitchen and, like every head of a multiple member family, I did a fast head check. Three mutts sleeping on the carpet in the hall, two missing. And since I had to get another cup of coffee anyway, I went to the kitchen to check.
It was not the two missing mutts however. They were schnoozing on the couch
it was the resident rodent who brazenly had chewed a hole in a new bag of doggie biscuits that I had left on the kitchen counter and had noisily been dragging biscuits to its lair.
And the worthless mutts, you might ask, what were they doing?
Being worthless is what they were doing. This was not a quiet operation, gnawing and hauling biscuits.
And when I heard some noise in the oven and opened the door, there was the culprit, not about to give up on the biscuit he had worked so hard for.
And now I know. It is not a mouse, it is a rat, but fortunately not of the slithery kind. My resident rat is light brown, fluffy and round ( no wonder, with all the doggie biscuits and other missing items ) and more a Disney type rodent, sort of hamster like and obviously not going away, and since the mutts don't seem to care, and I cannot kill it, we had better come to some arrangement. So.... NO hanky panky. I can, maybe, deal with this one, but a whole family...
NO WAY.
Now the problem remains, how do I explain this to the rodent ?