What’s the difference between an alligator vs a crocodile, and how do I remember which is which?

Both are members of the order Crocodilia, but they have different habitats, physical attributes, and levels of aggression.

Alligator– A reptile from the family Alligatoridae that has a broader, U-shaped snout, a darker coloration, and lives in freshwater.

Crocodile– A reptile from the family Crocodylidae that has a narrower, V-shaped snout, a lighter coloration, and lives in saltwater.

The quickest way to tell the difference between the two is to look at their snout shapes and body coloration.

Alligator vs Crocodile Classification

Alligators and crocodiles are reptiles which are vertebrate animals (they have backbones) that have scales, breathe air, and lay their eggs on land.

Both alligators and crocodiles belong to the order Crocodilia (sometimes spelled Crocodylia) which is an order of large, predatory reptiles that are semi-aquatic and spend part of their time in the water. These reptiles are called crocodilians.

The order Crocodilia has three families: Alligatoridae, Crocodylidae, and Gavialidae.

The family Alligatoridae includes alligators and caimans, the family Crocodylidae includes “true” crocodiles, and the family Gavialidae includes gharials.

The term crocodile refers to any crocodilian, so this means that technically all alligators are crocodiles, but not all crocodiles are alligators.

Location and Habitat

Alligators and Crocodiles live in very different locations.

Alligators are only found in the US and China, and crocodiles can be found all around the world.

In the US, alligators are the more common of the two (there are 3 million alligators and less than 2,000 crocodiles in the US).

Fun Fact: Florida is the only place in the world where alligators and crocodiles live together.

Alligators and crocodiles also have different habitats.

Alligators live in freshwater, but crocodiles live in saltwater or brackish water (water that is a mix of freshwater and saltwater).

Their preference for fresh or salt water may be in part to their lingual salt glands (glands that secrete excess salt from their bodies). While both alligators and crocodiles have these glands, alligators’ glands are non-functioning, and they cannot excrete enough excess salt to live in salt water.

Their habitats also affect their coloration.

Alligator vs Crocodile Coloration

Alligators and Crocodiles have different colorations that can vary based on their habitats.

Alligators are typically blackish gray, and crocodiles are typically olive green or tan.

Also, their coloration can vary depending on their water quality.

For example, if there is a lot of algae, then they are greener in appearance, and if there are a lot of hanging trees (or leaves in the water), they are darker in appearance due to higher amounts of tannic acid being in the water.

Algae makes me green!

Alligator vs Crocodile Snout Shape

One of the easiest ways to tell the difference between an alligator vs a crocodile is to look at the shape of its snout.

Alligator snouts are shorter, broader and U-shaped, while crocodile snouts are longer, narrower, and V-shaped.

These snout differences between the two may be due to their different diets.

Alligators typically eat a lot of turtles and crustaceans, but they are opportunistic feeders that will eat whatever is available to them. Their shorter, broader jaws are well-suited to breaking and crushing shells.

Crocodiles typically eat a lot of fish and reptiles, but they are also opportunistic feeders that will eat almost anything. Their longer, narrower jaws are well-suited to catching fish.

Both alligators and crocodiles also have sensory pits (called dermal pressure receptors) on their upper and lower jaws which help them detect pressure changes in the water (to help them to catch their prey).

However, alligators only have sensory pits on their jaws and crocodiles have them all over their bodies.

Also, even though their snouts are narrower, crocodiles have a more lethal bite.

Crocodiles’ bite pressure is 3,700 lbs. per square inch, and alligators’ bite pressure is 2,900 lbs. per square inch.

Fun Fact:  Crocodiles have the strongest bite force of any animal!

Their snout width also affects how visible their teeth are.

Alligator vs Crocodile Teeth

Another way to tell the difference between an alligator vs a crocodile is to look at its teeth.

When its mouth is closed an alligator’s bottom teeth are hidden, and a crocodile’s bottom teeth are not.

Crocodiles have two bottom teeth (the fourth ones from the front) that are always visible (they fit over their upper jaws when closed), and often you can see many of their other lower teeth as well. This gives crocodiles the appearance that they are “smiling.”

Alligators, on the other hand, have broad upper jaws that go over their bottom teeth, so this makes their teeth hidden when they close their jaws.

Fun Fact: Alligators can stick their tongues out, but crocodiles can’t! This is because the membrane that holds their tongue in place is on the roof of their mouth instead of the bottom of their mouth.

Tails, Legs, and Feet

Alligators and crocodiles have other physical differences as well such as their tails, legs, and feet.

Both alligators and crocodiles have scutes which are bony, external scales. But crocodiles’ scutes are longer and more pronounced than alligators’ scutes.

Crocodiles also have a jagged “fringe” on their hind feet and legs, but alligators do not.

And alligators have webbed front feet, but crocodiles do not (both have webbed back feet though).

Alligator Vs Crocodile 2

Alligator vs Crocodile Size and Weight

Alligators and Crocodiles also differ in size and weight.

Alligators are typically shorter and smaller than crocodiles.

Alligators can grow up to 14 ft long and weight up to 1,000 lbs. Crocodiles can grow up to 23 ft long and weigh up to 2,000 lbs.

Fun Fact: The largest crocodile is the saltwater crocodile and the second largest is the Nile crocodile.

Their size and weight also affect their speed.

Alligator vs Crocodile Speed

While both alligators and crocodiles can move quickly, they are much quicker in the water. On land, they can only run quickly for short distances.

Since they are smaller and lighter, alligators are faster than crocodiles on both land and water.

On land, alligators can run about 11mph, and crocodiles can run about 9 mph. However, in water, alligators can swim about 20 mph, and crocodiles can swim about 9 mph. That’s a big difference!

Alligator vs Crocodile Aggression

Alligators and crocodiles have different levels of aggression.

Crocodiles are more aggressive than alligators.

Alligators have an instinctive fear of humans and are timid when it comes to them. If approached by humans, they will often try and escape into the water to avoid confrontation. They will only attack if startled, provoked, or they are protecting their young.

However, it is important to note that they can lose their fear of humans if they are around them all the time or if they start to be fed by them. The lesson of the day: don’t feed alligators!

Crocodiles, on the other hand, are much more aggressive will attack humans even if unprovoked. The good news is that American crocodiles are timid compared to other species of crocodiles!

Fun Fact: The fatality rate for death by an alligator in the US is one every three years. You are more likely to be killed by a dog, a spider, or a shark than an alligator!

Final Thoughts on Alligator vs Crocodile

The quickest way to tell the difference between the two is to look at their snout shape and coloration.

Alligators have broader, U-shaped snouts and are typically darker in color, while crocodiles have narrower, V-shaped snouts and are typically lighter in color.

Alligators also only have sensory pits on their jaws and crocodiles have them all over their bodies.

Alligators and crocodiles also differ in habitat, have different physical attributes, and different temperaments.

Alligators live in freshwater, and crocodiles live in saltwater.

Alligators can hide their bottom teeth, but crocodiles cannot.

Alligators have shorter and less pronounced scutes, have webbed front feet, and do not have a jagged “fringe” on their hind legs and feet.

Alligators are typically smaller, shorter, and faster than crocodiles.

Alligators are less aggressive than crocodiles and are inherently scared of humans.

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