Alligators vs Crocodiles (12 Key Differences)

Modern day dinosaurs, alligators and crocodiles are some of the most notable apex predators in the animal kingdom. These giant, lizard-like animals are known for their fierce jaws, tough skin and prowess as hunters.

Alligators and crocodiles are closely related and are often mistaken for one another. So in this article we will be discussing the similarities, and more importantly the differences between alligators and crocodiles.

Alligators and crocodiles belong to a taxonomic group called an order. They are in the order Crocodilia, which consists of 24 different species of crocodilians. In the crocodilian order, there are the caiman and gharial, as well as several species of crocodile and two species of alligator.

You likely are familiar with some of the more well-known species of crocodilians, such as the American alligator, the American crocodile, the Nile crocodile and the Saltwater crocodile, but there are actually 14 different species of crocodile.

To keep things simple, we won’t go into great detail about all crocodilians- just some of the ones you may be familiar with.

Alligators vs crocodiles – 12 key differences

While there are many similarities shared between alligators and crocodiles, there are luckily some key differences that can help you tell them apart. These differences include aspects of their appearance, their behavior, and habitat.

However, there are also differences that are not visible to the eye that make these creatures unique from one another.

If you are in the United States, then the first thing to consider is where you are. American alligators are widely spread in the Southeastern United States, while the American crocodile can only be found in Southern Florida.

However, if you are in Southern Florida and you are unsure if the giant reptile you are looking at is a croc or a gator- then you will have to consider where you are on a finer scale. In other words, what habitat is the animal in?

Alligators are almost always found in freshwater habitats- swamps, lakes, wetlands, ponds, etc. while American crocodiles are associated with saltwater and are commonly found in bays, along shore lines, in saltwater canals, etc.

In other parts of the world, crocodiles may be more associated with fresh water, like the Nile crocodile, or both saltwater and freshwater like the Saltwater Crocodile. That being said, there is always an exception to every rule! Alligators, while uncommon, have been known to venture into the ocean.

If you are somewhere else in the world, then telling the difference between a crocodile and an alligator is easy! This is because there is only one other species of alligator, the Chinese alligator, while there are several species of crocodiles.

Alligator Crocodile
Average size 8-12 feet (American alligator)

5 feet (Chinese alligator)

9-20 feet
Distribution Southern United States, Eastern China Southern United States, Central and South America, Africa, Asia and Australia
Habitat Freshwater Saltwater, freshwater, brackish water
Color Very dark brown, almost black. Mostly uniform in color. Brown/tan, olive green with dark spots along the body and tail
Jaw shape U-Shaped V-Shaped
# of species 2 14

1. Distribution

As mentioned earlier, where you are in the world can help you decipher whether or not you are looking at an alligator or crocodile! There are American alligators, which are found in the Southeastern United States.

The only other species of alligator, the Chinese Alligator, has a restricted distribution and can only be found in a handful of freshwater bodies in a small part of Eastern China.

Any other crocodilian in the world is either a crocodile, a gharial, or a caiman. Crocodiles can be found in Asia, Australia, Africa, North and South America.

In the United States however, there are both American Alligators and American Crocodiles. American Crocodiles are only found in very Southern Florida.

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American Alligator

2. Habitat

In the United States, American Alligators stick to freshwater systems. They can be found in wetlands, ponds, lakes, and canals. American Crocodiles, however, live in saltwater systems and can be found along shorelines throughout Southern Florida.

Crocodiles have special salt excreting glands on their tongues that allows them to tolerate these saltier environments. Alligators have these glands as well, however they do not work the same way. Alligators may venture into salt-water based environments from time to time, but they won’t spend long there.

In other parts of the world, different species of crocodiles prefer different habitats. For example, the Nile crocodile is found throughout much of Sub-Saharan Africa in freshwater and brackish water bodies. The Saltwater crocodile is a marine crocodile found in saltwater in Australia and parts of Asia but they can also be found near the mouth of rivers.

3. Color

Alligators and crocodiles are actually quite different in color, despite many people confusing them. Alligators tend to be very dark, almost black and uniform in color. While crocodiles tend to be lighter in color and are more of an olive color or grayish brown, with dark splotches on their tail.

The coloration of a crocodilian species can almost mirror their environment. For example, American alligators can be found in swamps with dark, murky water and their darker coloration helps them blend in.

American crocodile

In contrast, the American crocodile can be found in brackish or salt water which is often clearer and lighter and their coloration can help them to blend in against sandy bottoms and brackish water canals.

4. Snout Shape

The snout or jaw shape is perhaps the best way to tell an alligator apart from a crocodile. The jaws of an alligator tend to be more broad, with the end of their snout in the shape of a U if you are looking at the jaws from above. Crocodiles have much more narrow snouts, almost in the shape of a V.

However, if you are in Southern Florida you may also encounter the invasive Spectacled Caiman- a close relative of the alligator. They also have a broad, U shaped snout, but their snout is typically shorter than that of an American alligator.

5. Jawline

Both alligators and crocodiles have large, powerful jaws with many teeth. When an alligator’s jaw is shut, you can typically only see the teeth on their top jaw poking out. However, crocodiles have a much toothier grin, and when their mouth is closed you can see both their top and bottom teeth protruding from their mouth.

6. Size

While both alligators and crocodiles have the ability to grow to be huge, generally speaking, adult crocodiles are larger than alligators by several feet. Adult American alligators grow to be 8.5 – 12 feet, with males growing larger than females. American crocodiles grow to lengths of 9 – 15 feet.

Nile crocodiles grow to be a similar size to the American Crocodile. However, the Saltwater crocodile out measures all other crocodiles, and is actually the largest living reptile. These modern day dinosaurs can grow to incredible lengths of 10 – 20 feet.

Nile crocodile

That being said, these are average lengths of wild alligators and crocodiles. When kept in captivity, crocodilians are known to grow several feet larger!

7. Temperament

While you certainly never want to get close enough to experience the temperament of a crocodile or alligator, alligators are known for being a little bit more laid back than their relatives.

Both crocs and gators are fierce predators that are capable of causing bodily harm or death to humans. However most of the crocodilian attacks on humans in the world are caused by crocodiles like the Saltwater crocodile or the Nile crocodile.

Alligators are more likely to go their own way or stay put when approached. Crocodiles will also flee, but are more likely to react defensively if they are cornered. When agitated, crocodiles and alligators may let out a deep growl or a loud hiss.

8. Sensory Organs

If you look closely at a picture of an alligator or crocodile, you may notice small, black dots covering their jaws. These are not just specks, but are actually integumentary sensory organs or ISOs.

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ISOs give crocodilians almost like a sixth sense. These small organs help to pick up minute pressure changes in the water around them, which can help them detect potential prey near them.

Alligators have ISOs all over their head and jaws, however crocodiles have ISOs that cover their entire body.

9. Jaw Strength

While the jaws of a crocodile or an alligator are undoubtedly very powerful, crocodiles have a bit of an edge when it comes to bite force.

Saltwater crocs have among the strongest bite force of any animal with a whopping 3,700 pounds per square inch. While American alligators can slam their jaws shut using 2,980 pounds per square inch of force.

To put things in perspective, lions have a bite force of approximately 1,000 pounds per square inch.

10. Cold water tolerance

Crocodilians are associated with warmer temperatures, with all species found in the tropics and sub-tropics. However, Alligators are able to withstand cooler temperatures than crocodiles.

Alligators can be found as far north in the United States as North Carolina whereas American crocodiles are only found in the very Southern tip of Florida and central and South America where the temps do not drop nearly as low.

In fact, Alligators can even survive sudden cold snaps when ponds and lakes freeze over. Alligators will brumate, which is the reptilian version of hibernation. During brumation, Alligators will submerge their bodies in the water, sticking their snout up so that their nostrils are out of the water. In these cold snaps, Alligators have actually been seen with their snouts protruding from an icy pond.

American alligator resting on grass

11. Evolutionary history

Both alligators and crocodiles look like modern day dinosaurs. And it’s no wonder because the ancestors of these reptilian giants have been around for hundreds of millions of years!

Crocodilian ancestors have been dated back to approximately 230 million years ago. However, our modern day crocodiles can be traced back to the late cretaceous period, approximately 70 million years ago. Their slightly younger relatives, the alligatoridae family (including alligators and caiman) is traced back to the early Tertiary or late cretaceous period- about 54-65 million years ago.

There has been little evolution of crocodilians over the past several million years and they still strongly resemble their prehistoric predecessors.

12. Species diversity

When it comes to the number of species, the crocodiles have outnumbered the alligators. There are only two species of alligators, as previously mentioned. However, there are 14 different species of crocodiles. But the alligators do have six different species of very close relatives; the caiman.


The other types of crocodilians

In addition to alligators and crocodiles, the crocodilian order also includes several other species such as caiman and gharials. They are closely related to alligators and crocodiles and some may even be confused for their crocodilian relatives.

Caiman

black caiman | image by Bernard DUPONT via Flickr | CC BY-SA 2.0

Family: Alligatoridae
Number of species: Six
Distribution: Mexico, Central and South America

Caiman are more closely related to Alligators than some of their other relatives. What makes caiman unique is their size as the average caiman is only between six to eight feet long at maturity. The smallest crocodilian in the world is the Cuvier’s dwarf caiman and does not exceed lengths of 5 feet. However, the Black Caiman can grow to be as large as 13 feet long.

Caiman are considered “new world” species, and are only found throughout Latin America. They are associated with freshwater bodies and can be found in marshes, swamps, rivers and lakes. The Spectacled caiman has also been introduced to South Florida where it is thought to have established and sustained a small population in the Greater Everglades.

Gharial

gharial | Image by Petr Stěhule from Pixabay

Family: Gavialidae
Number of species: Two
Distribution: India, Bangladesh, Malaysia, Borneo and Indonesia.

Perhaps the strangest looking of the crocodilians are the Gharials. There are only two species on Gharials, the Gharial and the False Gharial. What makes these species distinct from other crocodilians is their incredibly long and narrow snout. They almost look like something out of a cartoon with their slender yet toothy grin.

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These crocodilians are exclusively found in freshwater bodies, mainly rivers and streams. Their long jaws are perfect for catching smaller prey items like fish, as this is their main source of food. The gharials lack the same jaw strength as their crocodilian cousins and therefore have a more limited diet.


Alligator and crocodile FAQs

Do alligators and crocodiles live together?

Generally, no. But South Florida is a very unique place in the sense that it is actually the only place where you can find both Alligators and Crocodiles in the same place! They can be found sharing canals and even shorelines.

However, everywhere else, you will only find alligators or crocodiles. Despite this, alligators and crocodiles are capable of being kept together in captivity in the right conditions.

Are alligators or crocodiles more dangerous?

Both alligators and crocodiles have the potential to be dangerous to humans. With a bite force of 3,000+ pounds per square inch, you certainly would not want to find yourself in between the jaws of an alligator or crocodile.

Not only do crocs and gators have an incredible bite, but they use their strength and agility in the water to grab their victim, take hold and continuously roll them in the water- also known as the death roll. Neither crocs or gators are an animal you want to mess with!

That being said, crocodiles are responsible for the most crocodilian attacks in the world. An estimated thousand people per year are thought to be killed by crocodiles, with the Saltwater and Nile crocodiles responsible for the most deaths.

Nile crocodile | Image by mkraucht from Pixabay

In contrast, alligators are rarely associated with fatal human attacks. On average, there may be approximately one deadly alligator attack per year.

Are alligators and crocodiles endangered?

Nearly half of the species of alligators or crocodiles are listed as critically endangered or vulnerable to extinction by the International Union for Conservation of Nature (IUCN) redlist.

Crocodilians face numerous threats that make them vulnerable, such as being poached and hunted for their skin, killed out of fear or retaliation, habitat destruction and degradation, and climate change.

The American crocodile is listed as endangered, while the American alligator, Nile Crocodile and Saltwater crocodile are all listed as least concern.

What do alligators and crocodiles eat?

Despite their differences, alligators and crocodiles share similar diets. They are both generalist carnivores, meaning they will eat most vertebrates like birds, fish, and mammals that venture too close to the water’s edge.

They are opportunistic hunters that ambush their prey. This is one of their traits that can lead them to attacking humans and/or their pets that walk near the water.


Conclusion

In reality, there are more similarities between alligators and crocodiles than differences. However, as we discussed in this article, there are several differences that distinguish a crocodile from an alligator.

The text-book way to tell the difference between the two is the jaw or snout shape. If the crocodilian has a broad, U shaped snout, then you can assume it is an alligator. If it has a more narrow, V shaped snout, then you are looking at a crocodile!

Coloration is also a great way to identify a gator from a croc. Crocodiles tend to have lighter scales and come in light shades of brown, olive green, and can even have a yellow tinge. They also tend to have dark spots on their tails. Alligators on the other hand are very dark brown, and even look black in certain lights.

American Alligator

And lastly, where you are in the world can also be a key factor in determining what type of crocodilian you are looking at. If you are anywhere but Southern Florida in the United States, then it is most likely an alligator. If you are anywhere but the United States, then it is most often a crocodile!

That being said, the absolute best way to tell an alligator or crocodile is to really familiarize yourself with the subtle differences between them or ask an expert!