10 Differences Between Alligators and Crocodiles

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Many people are unaware that there’s a difference between alligators and crocodiles and use both terms interchangeably to describe any large water-dwelling lizard with big teeth. Coming face to face with a crocodile or an alligator, you’d see a mouth full of serrated teeth that would likely scare the bejeezus out of you. In this video we are lurking below the 10 differences between alligators and crocodiles.

10. Scientific Classification

The term “crocodile” refers to any species belonging to the Crocodilia order. However, true crocodiles belong to the Crocodylinae subfamily; other families in the order Crocodilia include Aligatoridae and Gavialidae. Alligators belong to the Aligatoridae family; consequently, they are only a family within the broader group of crocodiles, since this latter term can define a grouping of different species. In other words, alligators can be called crocodiles, but not all so-called crocodiles are alligators.

If you compare the specimens that belong to the Alligatoridae family with other species and families within the Crocodilia order, you can notice significant differences.

9. Behavior

Saltwater crocodile underwater opens mouth and teeth in Chinchorro Banco Mexico

In terms of aggression, an alligator might seem tame compared to a crocodile. Alligators, while definitely dangerous, are relatively timid compared to crocodiles. An alligator will generally try to escape if approached by humans, usually heading for the nearest water. The only time that wild alligators will attack humans is if they are unexpectedly disturbed, provoked, or defending their young. Alligators are instinctively afraid of humans but can lose some of that fear with regular contact. Except in controlled conditions, feeding them is almost always a bad idea as they will lose some of their fear and see humans as a source of food. They can also mistake small children and pet dogs for prey.

Crocodiles, on the other hand, are much more bad-tempered and far more likely to attack humans, even unprovoked. Australian saltwater crocodiles are generally considered the most dangerous in the world, followed by Nile crocodiles. American crocodiles, on the other hand, are one of the more timid types that you will find and rarely attack humans. In the US, you are more likely to be attacked by an alligator than a crocodile, although attacks by either are very rare.

8. Speed

Two crocodiles racing

On land and in water, crocodiles are usually slower than alligators. Both can move quickly on land, but only for short distances. They can both “gallop” or “sprint” but only do it when threatened, and not for long. A crocodile might reach almost 9 mph (14kph), while an alligator might reach a maximum speed of about 11 mph (18 kph).

In water they’re both much more agile and fast in water where they can use their long, muscular tails to propel their bodies forward. When crocodiles swim, they might reach speeds of about 9 mph (15 kph), while alligators might reach a maximum of 20 mph (32 kph).

7. Color

American Alligator

Crocodile hides tend to be more of a light tan or olive color, whereas alligators are usually a dark blackish grey. The exact shade of an alligator skin depends on the quality of the water it swims in. Tannic acid from overhanging trees will make them darker, algae will make them greener).

6. Size

Crocodile in Kenya River

A full-grown crocodile will likely be several feet longer than an adult alligator. An adult crocodile can grow up to roughly 19 feet long, whereas for alligators, the maximum length is around 14 feet.

Alligators can often reach at least 14 or 15 feet in length, which is larger than some crocodile species, but not others. The largest crocodile species is the saltwater crocodile, which can get to at least 17 or 18 feet – some rare individuals exceeding 20 feet after many years. The African dwarf crocodile, as a contrast, doesn’t grow larger than 4 or 5 feet.

5. Toothy grin

Alligator smiling

Crocodiles can’t hide their teeth, but alligators’ teeth are sometimes hidden when their mouths are closed. When their mouths are closed, the snouts of alligators and crocodiles are easy to tell apart, as the alligator will have none of its bottom teeth visible, whereas the crocodile’s lower fourth tooth can always be seen.

Crocodiles often have many visible teeth sticking out over their lips, giving them a very jagged “smile,” but since an alligator’s upper jaw is wider than its lower, it can hide all its teeth when its mouth is closed.

4.  Habitat

Crocodile swimming in the Gardens of The Queens Marine Park in Cuba

Crocodiles prefer water that is more saline or salty than the alligator’s preferred freshwater habitat. Crocodiles have special glands in their tongues which excrete excess salt from their bodies. This means that they are capable of spending days, or even weeks, at sea. Alligators also have these glands but they don’t work as well, so they usually stick to freshwater habitats, although they can sometimes be found in brackish water (a mixture of salt and freshwater). This difference explains why crocodiles have managed to spread across the islands of the Caribbean, and alligators haven’t.

3. Location

Map of crocodile habitats

Alligators live only in the southeastern US and eastern China, whereas crocodiles can be found across the world in Africa, Australia, Southeast Asia, North America, South America, and Central America.

If you are in the US, then you are far more likely to encounter an alligator than a crocodile. Although there is an American crocodile species, they only live in the southernmost tip of Florida, whereas alligators can be found across Florida and Louisiana, as well as in parts of Georgia, Alabama, Mississippi, North and South Carolina, Texas, Oklahoma, and Arkansas.

Alligators also heavily outnumber crocodiles in the US. There are over 3 million alligators, but fewer than 2,000 crocodiles. Southern Florida is the only place in the world where you will find crocodiles and alligators living side by side.

2. Shape of the Snout

One of the main differences between alligators and crocodiles is the snout. The alligator’s is broader and shaped like a U, whereas the crocodile’s is longer and narrower and more V-shaped. It’s very possible that the alligator’s snout shape is different because of diet, especially breaking open turtle shells, whereas the crocodile’s snout is more suited to hunting general prey including fish, reptiles, and mammals.

1. Bones

Researchers from Japan have identified what they believe to be another feature that sets the reptiles apart: Alligators tend to have shorter humerus bones in their forelimbs and shorter femurs in their hind limbs than crocodiles.

Masaya Iijima, a vertebrate paleontologist from Hokkaido University in Japan and lead author on the study, measured more than 120 alligator and crocodile skeletons from nearly a dozen museums across the world. Then he analyzed the results using a statistical model. The specimens mostly belonged to extinct crocodilians, which is the supergroup that encompasses both alligators and crocodiles, as well as caimans and gharials.

The differences are small, and not something you could easily spot in the wild. But the finding may provide insights into the ways in which the two reptiles move.

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