Crocodiles, alligators, and caimans all look very similar. They all look like huge lizards with tons of sharp teeth, so what are their differences and how can we tell them apart?
These are some of the few living descendants of the dinosaurs that look the same as they did 65 million years ago. They are all semi-aquatic and are found only in warmer climates.
They all belong to the order Crocodilia. Alligators and caimans both belong to the Alligatoridae family, so they are more closely related to each other than crocodiles, which belong to the Crocodylidae family.
There are 14 species of crocodiles, 2 species of alligators, and 6 species of caiman. How do we tell them all apart?
Where they live
Caimans live in Central and South America. Crocodiles can be found in the Americas, Asia, Africa, and Australia. Alligators are only found in the Southeast United States and Eastern China. The only place in the world where crocodiles and alligators can be found living together is Florida.
Alligators live only in freshwater. Crocodiles can live in freshwater and saltwater as they have salt glands on their tongue to get rid of excess salt.
Alligators have U-shaped snouts and many crocodiles have a V-shape, but not all. Caimans come in a variety of snout shapes, both U-shaped and V-shaped. Snout shape is not always the best way to tell the difference. You can use snout shape to tell the difference between an American Alligator and American Crocodile.
A better way to tell the difference between alligators and crocodiles is their teeth. Alligators and caimans upper jaw overlaps the lower jaw and teeth are not as visible with the mouth closed and you will just see their upper teeth.
Crocodiles upper and lower jaws are the same width. Crocodiles have interlocking teeth so when the mouth is closed, you will see both upper and lower teeth.
Integumentary sense organs
Another way to tell the difference is by the integumentary sense organs (ISOs), which are the dots you see all over the heads of both alligators and crocodiles. Crocodiles also have them all over their body, where alligators do not have them.
Here is an excellent video that shows what these look like:
Crocodiles have stronger bites than alligators. According to this National Geographic article, saltwater crocodiles may have the strongest bite of any animal.
Crocodiles have more webbing on the toes of the hind feet, which allow them to make fast turns and sudden moves in water.
Crocodiles are known to be more aggressive and likely to attack a human than an alligator. Australian saltwater crocodiles are believed to be the most dangerous followed by the Nile crocodile.
In the United States, you are actually more likely to be attacked by an alligator than a crocodile, but attacks by either is very rare.
Alligators and Caimans
You now know how to tell the difference between crocodiles and alligators/caiman, but how do you tell the difference between an alligator and caiman?
As mentioned above, alligators and caimans are from different parts of the world, so if you know where they are from you can determine which one they are.
Caimans are usually smaller than alligators with the exception of the black caiman, which can get up to 16 feet long.
Caimans lack of bony septum between nostrils (seen in the skull). They have longer and more slender/sharper teeth. Caimans have proportionally larger eyes located higher on the head.
Caiman scales are stiffer due to calcium deposits in the center of each scale. The scales on the bellies of caimans are made up of composite osteoderms, which are 2 or 3 plates that are sutured together, whereas alligators and crocodiles have single bone osteoderms
You now know the differences between crocodiles, alligators, and caimans! To tell them apart, look at how their jaws overlap with their teeth and look at whether they have ISOs on their bodies. If you are trying to determine whether it is an American Alligator or American Crocodile, you can use the snout shape method.