The eastern indigo snake (Drymarchon couperi, the genus name "Drymarchon" means "Lord of the forest") is the longest snake in North America, with the longest specimen ever found being over 9 feet long. They're native to the extreme southwestern United states, including most of Florida, as well as some bordering states. They're known for hunting venomous snakes, being immune to the venom of rattlesnakes. Rattlesnakes will even retreat from indigo snakes, instead of standing their ground and threatening to bite like they do with other predators. They don't specialize in hunting other snakes though, they're active predators that'll eat just about anything they can overpower.
They can also solve puzzles:
https://www.youtube.com/watch?v=UroBQsFecSQ 
