Can you spot the differences between an alligator and a crocodile? Here's how to tell.

See ya later, alligator! After a while, crocodile!

Aside from the silly farewell, could you spot the differences between a crocodile and an alligator if asked? They may look similar, but there are a few key physical and behavioral distinctions that divide the two.

One notable difference is their population size in the U.S. – American alligators are significantly more numerous in Florida than crocodiles. Florida American crocodiles are classified as a threatened species by the U.S. Fish and Wildlife Service but have been making a comeback in recent years.

What's the difference between an alligator and a crocodile?

Alligators and crocodiles both belong to the reptile suborder Eusuchia of the crocodilians, which also includes caimans and gharials. The differences between alligators and crocodiles became pronounced about 80 million years ago and continued as they survived the mass extinction of the dinosaurs, The New York Times reports.

The biggest difference between alligators and crocodiles is their snout shape – according to Britannica, alligators have a broad, U-shaped snout while crocodiles have a narrow, V-shaped one.

The two animals also have different teeth. Alligators have an overbite so their lower teeth are not visible when their mouths are shut. Crocodiles, in contrast, show some bottom teeth when their mouths are closed, especially their fourth largest tooth (think of the green monster from “Peter Pan”).

Other notable differences include:

• Color: Alligators are often gray or black, crocodiles are olive or tan

• Habitat: Alligators prefer freshwater, crocodiles saltwater

• Behavior: Alligators are less aggressive than crocodiles

A 2018 study published in the Royal Society Open Science journal also found crocodiles usually have longer humerus and femur bones than alligators.

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What is the size difference between a crocodile and an alligator?

According to the National Park Service, adult male alligators can reach 13 to 15 feet in length while adult females only reach 10 feet. Gators are often smaller in South Florida, the only place in the U.S. where both crocodiles and alligators exist.

Male crocodiles can reach up to 20 feet but often are only about 14 feet in the wild, and females are typically 8 to 12 feet long, NPS says.

Which is more aggressive, crocodile or alligator?

Crocodiles in general are often more aggressive than alligators, though American crocodiles are considered “shy and reclusive” compared to their international peers. Saltwater crocodiles are the more frequent attackers.

According to New Orleans Kayak Swamp Tours, alligators are “relatively timid” compared to crocodiles and will try to escape if approached by humans, only attacking if they’re provoked or defending their young. Unprovoked attacks are rare, though American alligator attacks are more common than American crocodile attacks. This may be because there are fewer crocodiles than alligators in the U.S.

Nile crocodiles and saltwater crocodiles, found in Sub-Saharan Africa and India, Southeast Asia and Australia, have the strongest bite force of any animal. American alligators have an impressive bite as well, though their 2,125 pounds per square inch (psi) bite pales in comparison to the Nile crocodile’s 5,000 psi. For comparison, a human’s bite force is about 162 psi.

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This article originally appeared on USA TODAY: What's the difference between an alligator and a crocodile? We unpack.