Alligator Skull - American alligators are found in the southeastern United States from Virginia along the Atlantic coast to Florida and into the Gulf of Mexico Texas. This large freshwater alligator generally resides in swamps, rivers and lakes but can tolerate some salinity and brackish environments. This species can burrow and hibernate during cold seasons. Alligators can reach a length nearly 15 feet (4.5 M) and, historically, have been recorded at lengths up to 20 feet (6 M). Alligators are carnivores, feeding on small vertebrates including fish, turtles, mammals, birds and carrion.