You can distinguish an alligator from a crocodile is by looking at the teeth. The large fourth tooth in the lower jaw of an alligator fits into a socket in the upper jaw and is not visible when the mouth is closed. A crocodile’s fourth tooth is always exposed.
Spanish sailors visiting the New World thought the unfamiliar alligator was a huge lizard. In Spanish, ‘el lagarto’ means the lizard. English sailors took the name as ‘allagarter’ and in time it has become alligator.
Alligators have been around since the time of dinosaurs. The Chinese alligator of Eastern Asia and the American alligator of the southeastern United States are the only two species to have survived evolution.