Whats the difference between an alligator and a crocodile?
Both alligators and crocodiles are members of the reptilian order Crocodylia. But the families they belong to, Alligatoridae and Crocodylidae respectively, differ. Often, when people use the word “crocodile” what they really mean is “crocodilian.” This term encompasses not just the common alligators and crocodiles you might already know, but also the lesser known Gavialidae family that contains the lone gavial, or gharial. All told, there are 23 species of crocodilians.
Well the commonly used difference (which is kinda illustrated here) is the snout shape. Alligators generally have wider and smoother snouts, while crocodiles have more triangular and thin snouts. But this isn’t always true and some fossil crocodylians have snouts that can get confusings. For instance there is a species of now extinct caiman with a snout nearly as thin as Tomistoma schlegelii (the false gharial). So how does one really tell the difference? It’s all in the teeth. Alligator and caiman bottom teeth fit snuggly in the roof of the mouth in special pits. In crocodiles these teeth fit into special grooves on the outside and thus end up showing when the mouth is closed. For more on this head to thecrocodylians section.
