While alligators are often confused with
crocodiles, they belong to two quite separate families, and are as distinct from one another as humans are from gorillas.
Alligators strongly prefer fresh water, while crocodiles live in both fresh and salt water. They can live in salt water because of a special gland to help filter the salt from the water.
Crocodiles tend to be more aggressive than alligators.
In regards to appearance, alligators differ from crocodiles principally in having wider and shorter heads, with blunt snouts; crocodiles have a longer, narrower snout, with eyes placed farther forward on their head. Alligators have U-shaped heads, while crocodiles are V-shaped.
In regard to their jaws, only the upper teeth are visible when an alligator's mouth is closed, while a crocodile's mouth will reveal both upper and lower teeth, as their fourth tooth sticks out from the lower jaw. An alligators' jaws are meant to crush bone, while in contrast, a crocodile jaw is much more narrow and are used to tear and grip prey.