Alligators and Crocodiles (Order Crocodylia) are the modern representatives of an ancient lineage of reptiles, dating back to the time of the dinosaurs. Amazingly, these animals have remained virtually unchanged over millions of years. Crocodilians are found throughout the warmer parts of the world, with 21 species present worldwide. Only two species, the American Alligator and American Crocodile are native to the United States. While the American Crocodile is restricted to brackish habitats in Southern Florida and the Caribbean, the American Alligator is restricted to fresh water and ranges throughout the Southeastern United States.