Alligators are large reptiles, members of the order Crocodylia. Alligators and crocodiles are, therefore, closely related, and people often confuse one with the other; however, these two reptiles are very different.
An alligator is distinguished by its wide, rounded snout and black color. Also, all of its upper teeth can still be seen when its mouth is closed. Crocodiles, on the other hand, have narrow, pointed snouts, a grey-green color and only the fourth tooth on the lower jaw can be seen when the animal's mouth is closed.