[Salamander]

Yep.

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

God knew what He was doing.

[DCBryan1]

Yep. God is perfect. You need to acquire a handful of either one of these, preferably the kingsnake since it has the propensity to kill everything but other kingsnakes, esp. poisonous snakes.

Speckled king snake (Lampropetus g. Holbrooki)

OR

...if you don't have a snake problem like we do in AR (copperheads and cottonmouths)...get a

P. Obseleta obseleta (black rat snake). The problem with them, though is that if you have bats, eastern bluebirds, purple martins, swifts, or swallows, or chickens/ducks they have a propensity to raid those nests for chicks and eggs.