Of the 21 crocodilian species known to science, only two are native to the U.S.A.: the American alligator and the American crocodile. Its broadly rounded snout distinguish the American alligator from the American crocodile, which has a sharper snout.

The American alligator inhabits coastal marshes and inland waters of the southeastern United States (usually in freshwater), from the southern Virginia-North Carolina border to the Rio Grande in Texas.

The young have bold yellowish crossbands on a black ground. They grow from about 23 cm long (9 in.) at hatching up to 5 m long (16.5 ft.). Adults are generally black, but they can retain some light markings of the young.

Breeding takes place in shallow waters during the night, in early May. A large nest of vegetation, 1 to 2 m in diameter (4 to 7 ft.) is built by the female, where she will lay 35 to 50 eggs in late June and early July. The eggs are covered with the vegetation nest and hatch at the end of August, once the female has removed the nesting vegetation from over the eggs.