Crocodilians include alligators, caymans, crocodiles, and gavials. There are more than 20 species of crocodilians, all of which live in or near water. These reptiles have a long snout, strong jaws, and webbed hind feet. They use their long, powerful tail to swim. All except a few crocodilians dwell in the fresh waters and lowlands of the tropics. Alligators live in the Southeastern United States and in Southern China.