Alligator Snapping Turtle vs Common Snapping Turtle: What Are The Differences?

Snapping Turtle with mouth open
© LA Dawson, CC BY-SA 2.5, via Wikimedia Commons

Written by Colby Maxwell

Updated: January 23, 2023

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Alligator and common snapping turtles look truly prehistoric. While both of these turtles share many similarities, they aren’t actually all that closely related. Still, many people confuse the two and don’t know what makes them unique. Today, we are going to remedy that. Let’s discover: Alligator Snapping Turtle vs Common Snapping Turtle; what are the differences?

Comparing an Alligator Snapping Turtle and a Common Snapping Turtle

Size is a major difference between both turtles.
Alligator snapping turtleCommon snapping turtle
TaxonomyFamily: Chelydridae
Genus: Macrochelys
Family: Chelydridae
Genus: Chelydra
SizeLargest: 249 lbs
Average: 20-175 lbs
Largest: 75 lbs
Average: 10-35 lbs
AppearanceHeavily ridged shells. Beaked mouth.Smooth, rounded shells. Highly mobile in the water. Long, serpentine neck.
DistributionFreshwater in the United States. Primarily in bodies of water leading to the Gulf of Mexico.Most of the United States, excluding the West Coast and desert regions.
TonguesUses lingual luring to attract fish.Fleshy tongues. No lures.

The 5 main differences between an Alligator Snapping Turtle and a Common Snapping Turtle

The main differences between alligator and common snapping turtles are that alligator snappers are larger, have heavy ridges on their shells, and have a smaller distribution. Common snappers are smaller, have smooth shells, and have a wider distribution.

Alligator snapping turtles and common snapping turtles are both famous for their strong jaws and “aggressive” nature, but these turtles aren’t the same species. While both belong to the Chelydridae family, they split into their own genus and have their own associated species. Despite both being referred to as “snapping turtles”, they aren’t that closely related.

The easiest way to tell the difference between these two turtles is through their size and their shells. Alligator snappers are extremely large, often weighing hundreds of pounds. Additionally, they have heavily ridged shells that resemble something you would see in a Jurassic Park movie. Common snappers are large, just a lot smaller than alligator snappers. They also have smoother, rounder shells.

Additionally, the location where these turtles are found is slightly different. Although they do have significant overlap, common snappers have a much wider distribution, whereas the alligator snapper is only found in the southern regions of the United States.

Let’s take a closer look at alligator snapping turtle and common snapping turtle and see what makes them so unique!

Alligator Snapping Turtle vs Common Snapping Turtle: Taxonomy

Alligator Snapping Turtle vs Common Snapping Turtle

Both species are related but belong to different genera.

©Sista Vongjintanaruks/

The alligator snapping turtle belongs to the Chelydridae family, a group of turtles that contains all living snapping turtles. Within that family, alligator snappers are classified within the Macrochelys genus. The Macrochelys genus is home to the largest freshwater turtles in the world, all of which live in the Southeastern United States.

Common snappers also belong to the Chelydridae family and are among the two extant genera within the family. The Chelydra genus is the only other genera within the family and is the category that common snappers fit into. Chelydra contains three species, all of which live in the Americas.

Alligator Snapping Turtle vs Common Snapping Turtle: Size

Alligator Snapping Turtle vs Common Snapping Turtle

Common snapping turtles are significantly smaller than alligator snapping turtles.

©Willy Logan / Creative Commons – Original

The alligator snapping turtle isn’t just large; it’s the largest freshwater turtle in the world. These massive creatures sit on the bottom of slow-moving water, rarely moving except to breathe. On average, the alligator snapper grows to 20-175 lbs in the wild, although they can get much, much larger.

The common snapping turtle is large, just not as large as an alligator snapper. The common snapper averages 10-35 lbs and never stops growing through life. The largest common snapper to have ever been found in the wild is listed at 75 lbs.

Alligator Snapping Turtle vs Common Snapping Turtle: Appearance

Alligator Snapping Turtle vs Common Snapping Turtle

Alligator snapping turtles have ridged shells, while common snapping turtles have smooth ones.


You can tell the difference between the two species in two ways. The primary visible difference is the shell. Alligator snappers have large shells with three distinct dorsal ridges across them. These ridges stick out and make the turtle look like a prehistoric dinosaur and less like a turtle. Additionally, they have distinct beaks with sharp points.

Common snappers have large rounded shells with smooth tops. If trying to differentiate the two, a smoother shell means you are likely looking at a common snapper. Additionally, their beaks don’t appear as pointed as the alligator snappers, although they can have a sharp bite. Most of the time, their mouths appear more receded than their distant cousins, however.

Alligator Snapping Turtle vs Common Snapping Turtle: Distribution

Alligator Snapping Turtle vs Common Snapping Turtle

Common snappers live across most of the United States.

©Tyler Clemons/

The only place that alligator snappers can be found is in the American Southeast. They almost exclusively live in waters that connect to the Mississippi and head towards the Gulf of Mexico and don’t occur in isolated ponds or wetlands all that often. They prefer regions with overhang, canopy, and beaver dens.

As their name suggests, common snapping turtles are a lot more common. They can be found through most of the range of alligator snappers, but with the addition of the entire east coast up to Maine, the Midwest, and west of the Mississippi, all the way to Idaho.

Alligator Snapping Turtle vs Common Snapping Turtle: Tongue

An interesting trait of the alligator snapper is its tongue. They use lingual luring, a tactic where they wiggle their worm-like tongue in order to attract fish to eat. Since alligator snappers don’t move very much, their passive hunting works well for them.

Common snapping turtles don’t have the ability to lure fish in with their tongues. Since they are significantly more mobile than alligator snappers, it isn’t as much of a need.

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About the Author

Colby is a writer at A-Z Animals primarily covering outdoors, unique animal stories, and science news. Colby has been writing about science news and animals for five years and holds a bachelor's degree from SEU. A resident of NYC, you can find him camping, exploring, and telling everyone about what birds he saw at his local birdfeeder.

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