[MrEdd]

I used to catch speckled kingsnakes in the woods and release them under the house for this type of problem. Obviously that only works with a pier and beam home.

[Salamander]

Yep.

All the other suggestions will fail with any but the dumbest rats.

God knew what He was doing.

[DCBryan1]

Yep. A 4-5 ft kingsnake or ratsnake (P. obseleta) thrown into the attic or crawl space will massacre your pest problem. I carry a pillowcase with me in my truck. If I see one, I'll grab it and take it home and throw it behind the barn or shed.

Kingsnakes, esp. L. G. Holbrooki subspecies are murderous little bastards that will keep killing chipmunks, rats, mice, moles, voles, and snakes ESPECIALLY poisonous snakes) until it finds itself in the open and a hawk or eagle gets it.