How to Tell the Difference Between a Tortoise, Terrapin and Turtle

Co-authored by Anthony Menendez

Last Updated: July 7, 2024 Approved

Turtles, tortoises and terrapins are closely related reptiles of the order Testudines. These terms are often confused because of regional differences in English, and because the individual species look similar. Scientific taxonomy uses precise terminology to distinguish different species, but they can also be commonly classified on the basis of habitat, body type, and behavior: turtles dwell both in water (either saltwater or freshwater, depending on the species) and on land, terrapins dwell both in freshwater and on land, and tortoises are land-dwellers.

Method 1

Method 1 of 3:

Checking the Body Type

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1
Examine the feet. Turtles and terrapins tend to have flattened, webbed feet for swimming.^{[1]
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Research source} Sea turtles are especially adapted for life in the water, with streamlined bodies and long, flipper-like feet.^{[2]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} Tortoises, however, don't swim—they have blunt, stumpy feet for walking on land. Their rear legs are elephantine, while their front legs are shovel-like for digging.
- Top photo: Tortoise
- Bottom Photo: Terrapin and turtle
2
Determine the shell type. Tortoises, terrapins, and turtles have scaly skin and protective shells. With a few exceptions (like leatherback sea turtles), the shells of turtles are hard and bony.^{[4]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} Tortoise shells tend to be rounded and domed, while turtle and terrapin shells are flatter.^{[5]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt}
- Top photo: Terrapin and turtle
- Bottom Photo: Tortoise
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3
Look for any distinguishing marks. If you suspect that you are observing a particular species of turtle, terrapin, or tortoise, look for markings on its shell or body that can help you determine this. For instance:
- The Diamondback Terrapin may be identified by the diamond-shape pattern on its shell.
- The Red-eared Terrapin may be identified by the distinctive red stripe on each side of its head.
- The Alligator Snapping Turtle may be identified by the pointed, peaked ridges on its shell.

Method 2

Method 2 of 3:

Observing the Reptile’s Behavior

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1
Watch for periods of reduced activity. Turtles will burrow into mud during cold seasons and go into a state called torpor (similar to hibernation).^{[6]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} During this time, the turtles’ activity is minimal. They will remain in this state until warmer weather returns.
- Limited evidence shows that terrapins may also spend some time hibernating in mud, or in periods of reduced activity.
Eating habits of turtles will vary greatly by species and environment, but can include plants, insects, and other small animals. Since they are land dwellers, tortoises tend to eat low-lying plants such as grasses, shrubs, and even cacti.^{[7]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} The diet of terrapins has not been thoroughly studied.
Land-dwelling tortoises will build nesting burrows and lay eggs. Species of turtles and terrapins that spend time both on land and in water, as well as sea-dwelling turtles, will all leave the water to lay their eggs.

Method 3

Method 3 of 3:

Examining the Environment

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Turtles spend most of their lives in water. Depending on its species, a turtle may inhabit fresh water (ponds and lakes) or the sea.^{[9]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt}
Tortoises are land dwellers. Some tortoises live far from major sources of water, such as in deserts.
Terrapins spend time both on land and in water. However, they inhabit brackish waters such as marshes. Often the term “terrapin” is only used to refer to certain species living in marshes of the Eastern and Southern United States, such as the Diamondback Terrapin, or the Red-eared Terrapin (also called the Red-eared slider; this is a common pond and pet turtle).^{[11]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt}^{[12]
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www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt}
Turtles and terrapins will leave the water to bask in the sun on logs, sand, rocks, and other surfaces.^{[13]
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Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} Sea turtles typically spend more time in water, but will leave to bask in the sun on beaches, reefs, and similar areas.

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In Australia, only sea turtles may be called “turtles,” while other species of turtles, tortoises, and terrapins called tortoises.^{[14]
X
Research source
www.acsu.buffalo.edu/.../TURTLES%20AND%20TORTOISES.ppt} In British English, “turtle” may refer to species living primarily in water, with “tortoise” used for those living primarily on land. American English may follow the same distinction, or refer to all as “turtles.” In all cases, these non-scientific terms are highly variable and inconsistent.

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Size is not a reliable indicator of whether a species is a turtle, tortoise, or terrapin, as there is variation within each category.

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If you already have a pet reptile and cannot determine if it is a turtle, tortoise, or terrapin, ask your veterinarian for advice.

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