The Shell Game

Ever wonder what the difference is between a turtle and a tortoise? They’re both shelled reptiles so is it all just a name? Not exactly. All tortoises are turtles, but not all turtles are tortoises.

Desert tortoise (NPS)

A tortoise is a turtle that lives exclusively on land, while most (but not all, remember there’s always an exception) turtles spend most of their time in the water. Because of the lifestyle differences, turtles have webbed feet and tortoises don’t. And of course sea turtles, who only come on land to lay eggs, have flippers instead of legs. Tortoise shells are generally taller, while turtles have a flatter, more aquadynamic shell design.

Box turtle (NPS)

Loggerhead sea turtle (USFWS)

Now that you have that down, let’s introduce the terrapin. Terrapins are mix of the landlubbing tortoise and seafaring turtle. They spend half their time on land, half in the water. They have a more streamlined shell than a tortoise, yet it’s taller and rounder than a turtle’s. 

Diamondback terrapin (USFWS)

This week's compare and contrast is from the National Marine Life Center.