Oklahoma’s two largest turtles, the alligator snapping and common snapping turtles, may share many features but a wild double take can reveal differences in the scales on the top shell, the hooked beak, and smoothness of the tail. 

Find tips for identifying Oklahoma’s look-alike species in our video series on YouTube.

Similarities: The alligator snapping and common snapping turtles are both large, water-dwelling turtles. They have large heads and long tails that, because of their small bottom shell, cannot be fully pulled into the safety of their shells. Though both species are closely tied to aquatic habitats, their eggs must be laid in a nest on dry land. The young have three prominent ridges on the top of the shell. These ridges are retained by adult alligator snapping turtles but become less apparent in adult common snapping turtles. Both species have hooked beaks and eat a variety of prey items, essentially eating anything they can catch.  

Differences: Despite their similarities, these snapping turtles can be identified by a few key features. As mentioned above, alligator snapping turtles retain the three prominent ridges on their top shell into adulthood. They also have an added row of scales, or scutes, near the edge of the shell and a smooth tail. Alligator snapping turtles have a much more prominently hooked beak than common snapping turtles and have a unique, worm-like “lure” that can be seen when the mouth is opened. These turtles are sit-and-wait predators and may use the lure to attract prey into their open mouths. Alligator snapping turtles can grow to be quite large – weighing up to 250 pounds – and have been documented in deep rivers, oxbow lakes, and sloughs in eastern Oklahoma. They are considered a species of greatest conservation need in Oklahoma and have a closed season.  

In contrast, common snapping turtles have fewer rows of scales on the top shell, a less pronounced beak, and a tail with saw-tooth projections. Though there is a lot of overlap in the size and weight of the two species, full-sized common snapping turtles are generally smaller than full-sized alligator snapping turtles. (The maximum weight of a common snapping turtle is thought to be around 85 pounds.) These turtles can be found statewide and are more active on land than alligator snapping turtles. Snapping turtles found moving in the spring and summer are by-and-large common snapping turtles.  

If you encounter a turtle while exploring Outdoor Oklahoma, consider sharing the sighting on free nature platforms like iNaturalist. Adding a photo to your observation can allow others to help confirm the identification. 

These Oklahoma look-alikes are included in the Wildlife Department’s “A Field Guide to Oklahoma’s Amphibians and Reptiles.” Tips for identification, a map of the Oklahoma range and information about the diet and preferred habitats are provided for 135 of the species that can be found in our state. The book’s spiral binding makes it easy to flip through and make comparisons of different species when identifying animals at home or in the field. Copies are available at GoOutdoorsOklahoma.com.