The crocodile's skull and jaws are longer and narrower than the alligator's. In both alligators and crocodiles, the fourth tooth on either side of the lower jaw is exceptionally long. When an alligator closes its mouth, those long teeth slip into sockets in the upper jaw and disappear. When a crocodile closes its mouth, the long teeth remain visible, protruding outside the upper jaw. In general, if you can still see a lot of teeth even when the animal's mouth is closed, you are looking at a crocodile.
Alligators have plenty of teeth, but fewer show until the mouth is open.
The American alligator , Alligator mississippiensis , resides primarily in the rivers and wetlands in the southeastern region of North Carolina, but can also be found as far north as the Albemarle Sound. Coastal North Carolina is the northern most range for the American alligator. Like sharks, crocodilians never run out of teeth, for sharp new ones grow in as old dull ones are shed throughout the animals' lives. Numerous as they are, crocodilian teeth serve only for grasping, not chewing. These animals gulp their food in large chunks and rely on powerful stomach acids to break it down.