Do you know what the difference is between turtles and tortoises? What about terrapins? They do look somewhat similar, but the three also have distinct differences that make them unique. 

Before we get into those differences, though, let's take a look at what makes turtles, tortoises, and terrapins so similar. For starters, they are all reptiles. That means that they all have scales, lay eggs, and are ectothermic (meaning that they need an external heat source such as the sun or a heated rock to regulate their body temperature.) 

Turtles, tortoises, and terrapins all belong to the taxonomic order called Chelonia (from the Greek word for tortoise). So they are often referred to as chelonians by ecologists. They also all have shells which are actually fused bone consisting of the rib cage and spinal cord.

What makes these three species unique depends a lot upon where each animal lives and how they use their habitat. 

Here's a closer look at each:

1. Turtles

Turtles spend most of their lives in the water. Sea turtles, like the one pictured above, spend almost their whole lives in the water aside from a brief period in which the females come ashore to lay their eggs.

If you look closely, you will notice that turtles bodies are made for life in the water. They have webbed feet to help them swim. They are also streamlined to help them glide through the water. 

Turtles live in oceans, rivers, lakes, and ponds. They may occasionally come out of the water onto reefs, banks, or logs to bask in the sun. They may also burrow in the mud where they will go through torpor to wait out colder temperatures.

Turtles eat small fish, jellyfish, and insects.

Green sea turtles, box turtles, and alligator snapping turtles are all types of turtle species.

2. Tortoises

While turtles love to spend their days and nights in the water, tortoises live completely on land. Rather than webbed feet, tortoises have round and stumpy feet that are perfect for walking on land. They typically have long claws that are used for digging. 

Tortoises eat small shrubs, grasses, and and other low-growing plants. On hot days, tortoises will dig burrows into the ground to escape the sun's heat.

Unlike turtles and terrapins, tortoises can also completely retract their heads into their shells.

Desert tortoise, Egyptian tortoise, and leopard tortoises are all types of tortoises species.

3. Terrapins

And last but not least, we have the terrapins. Terrapins, often called 'diamondbacks,' because of the angular rings on their shells. Terrapins spend some time in both land and water. They tend to live along rivers, lakes, and ponds in swampy or brackish waters. 

They are good swimmers, but they don't have webbed feet or fins. And while they are streamlined like turtles, they have a hard shell like tortoises. The word “terrapin” actually comes from an Algonquian word for turtle.  

Terrapins eat shrimp, clams, crabs, mussels, and other marine invertebrates, especially periwinkle snails.

In the U.S., there are seven subspecies of terrapin: northern, Carolina, tequesta, mangrove, ornate, Texas, and Mississippi.

Turtles, Tortoises, and Terrapins, Oh My!

Now that you know the difference between these three reptiles - turtles, tortoises, and terrapins, you can learn more about the issues that face and sometimes threatened these species and their habitats.Ecologists estimate that almost half of the world’s chelonians are at risk due to habitat degradation, hunting, climate change, and environmental pollution.