How are they different?

Alligators have a wide U shaped jaw, whereas crocodiles have a longer V shaped nose. The gator's upper jaw tends to be wider. Both gators and crocs have salivary glands..however the crocs' glands actually function making them more tolerant to living in salt water. Certain types of gators also tend to be more docile than most crocs.

Well their only one way to tell the difference between alligator and crocodile is by looking at their snouts.Alligators and their close relative, the caiman, have broad, rounded snouts. Crocodile have longer, sharper snouts that are shapes like triangles. Crocodile have a tooth on each side of their lower jaw that sticks up when tehir mouth is closed.Alligators do not show any teeth when their mouth are closed.