Stock Photo - American alligator (A. mississippiensis) in the Florida Everglade. they are crocodilian and in the genus Alligator of the family Alligatoridae. An average adult American alligator´s weight and length is 360 kg (790 lb) and 4. 0 m (13. 1 ft), but they sometimes grow to 4. 4 m (14 ft) long and weigh over 450 kg. Alligators are native only to the United States and China. American alligators live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, and swamps, as well as in brackish environments. When they construct alligator holes in the wetlands, they increase plant diversity and provide habitat for other animals during droughts. They are, therefore, considered an important species for maintaining ecological diversity in wetlands. . . .