Most people have trouble telling the difference between a crocodile (of the crocodylidae family) and an alligator (of the alligatoridae family). At first glance, they look alike: long, with sharp teeth.
However, to the astute observer, the crocodile and the alligator have very different mouths. The crocodile’s snout is long, thinner and shaped like a “V.” The alligor’s mouth is wider and is shaped like a “U.” The shape of the mouth leads to other differences. Alligators can catch prey—like turtles—and crush the shells with their mouth. Crocodiles, on the other hand, are better designed to catch fish and other mammals.
And though the crocodile and the alligator both have sharp teeth, these are shaped differently. The crocodile’s symmetrical jaws have teeth that interlock, which are all exposed. The alligator’s upper jaw is wider than the lower jaw, so part of its teeth are hidden.
Crocodile skin is olive brown, which makes them practically undetectable in the brackish water they like to dwell in. Alligators have darker, black-like skin.
Experts also say that crocodiles and alligators have followed different evolutionary paths. One big difference is that crocodiles can stay in salt water for long periods, and alligators can’t. Alligators prefer fresh water. While both had ancestors that lived in the ocean, alligators are more “removed” from their sea-dwelling roots.
For example, crocodiles have glands that can remove salt from their bodies. They also have more sensory pits – located not just in the upper and lower jaw (like alligators) but all over their entire body. This enables crocodiles to react to levels of salinity, but also to every change in water pressure. That’s one reason why crocodiles are very efficient predators, and why alligators seem more “docile”.