These crocodylia share a common evolutionary ancestor, but about 80 million years ago – during the Late Cretaceous period the Alligatoridae and Crocodylidae diverged and continued their own evolutionary journey. Over millions of years of evolution, crocodiles and alligators have remained relatively similar in appearance, but there are some easily recognizable differences.
Physical Difference
At first glance, crocodiles and alligators look very similar, but on closer inspection, they both have very different snouts. There is one quick way to tell crocodiles from alligators, look at their jaws. (Read also; Get to know 13 types of pythons in Indonesia )
According to Biology and Evolution of Crocodylians, crocodiles have an overbite, so the teeth in the lower jaw go into the upper jaw and are hidden. The teeth in the lower row of the crocodile’s jaw, on the other hand, are located on the outside of the mouth and fit into a groove along the upper jaw.
The shape of their head is also a key identifier. Crocodiles have a broad, short round U-shaped snout, while alligators have a more pointed V-shaped snout. According to the San Diego Zoo Wildlife Alliance, there are some exceptions to the rule, such as the robber crocodile (Crocodylus palustris), which also has a rounded snout.
Then, both of these reptiles have small black spots called integumentary sense organs (ISOs) on their heads. These sensory organs allow predators to detect changes in pressure in the water caused by their potential prey.
According to the Journal of Experimental Biology ISO can only be found on the head and around the mouth of crocodiles. While the alligator has ISO in almost every part of its body. The difference between the two reptiles is also more than the structure of the skin.
In a study published in 2018 in the journal Royal Society Open Science, researchers found that, compared to crocodiles, the alligator’s forelegs have a shorter humerus and the hind legs have a shorter femur.
Where do crocodiles and alligators live
According to a study published in the Journal of Comparative Physiology, one of the main differences between alligators and crocodiles is where they live. Crocodiles have lingual salt glands – on the tongue – which allow them to remove excess salt from the body.
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