Is it a turtle, a terrapin, or a tortoise?

Recently, the National Marine Life Center welcomed Lindsay, a diamondback terrapin, to the family. Two Eastern box turtles, Daisy and Violet, are also NMLC residents in the Discovery Center. Next door in our hospital, Jedi, Nicky, and Gunst, our three Kemp’s ridley sea turtles, are in the recovery process and on their way to being released.

With all of these similar reptiles, it might be hard to see the differences between the name “turtle,” “tortoise,” and “terrapin.” They are all ectothermic, which means that their body temperature is based on the temperature of the air or water around them. All three lay eggs, breathe air, and have scales and shells. So, where do the differences lay? Let’s begin with turtles, which spend most of their lives in the water. Because of this, their feet are normally webbed, or in the case of sea turtles, are longer and form flippers. This helps them swim fast and strong. Also, their body is more streamlined than their tortoise and terrapin relatives. Turtles will leave the water to lay their eggs or to bask in the sun when they are cold. In the winter, they might even dig a hole into the mud of a river bank and sleep until spring comes! They eat jellyfish, sea sponges, and seaweed and kelp in the ocean. In freshwater, turtles will eat plants, insects, and even small fish.

Next is the term “terrapin,” which is given to turtles that live in the water less frequently and live near brackish, or a mixture of salt and freshwater such as a marsh, and swampy areas. They’re a ‘middle ground’ between a tortoise and a turtle, as they will spend about half of their time on land and half in the water. Their shells also reflect their similarities to the two, as they will be a mixture of the streamlined and dome-shaped shells of the turtle and tortoise, respectively.

Finally, we will look at the term “tortoise.” These reptiles live only on land and therefore do not have webbed feet. Instead, their feet are rounded and more stumpy, which allows them to walk on land and to dig burrows for themselves. They will sometimes go in the water to cool off or to drink  water, but they are really bad swimmers. Tortoises can eat low-growing shrubs, grasses, cacti, fruits, and other plants. Their shells have more of a dome shape, as well, since they do not need to have a streamlined shell to allow them to swim quickly! The largest tortoise in the world, the Galapagos tortoise, can weigh over 900 pounds!

These terms are even different depending on where you live! For example, in Australia, all of these animals, besides sea turtles, are called ‘tortoises.’ This makes things a little more confusing! But remember- the difference mainly depends on where the reptile lives, what it eats, and the shape of it’s shell!

Posted by Caroline R.
Caroline is a Summer, 2016 intern at the National Marine Life Center. She  is currently a student at Bristol Community College, where she studies Environmental Science.