What is the difference between a turtle, tortoise, or a terrapin? There are common-use differences between them, and a specific scientific difference.

Science tells us that all shelled reptiles are chelonians, most commonly called turtles. Within the order of turtles, one family, Testudinidae, are the ‘true tortoises’- turtles that live, hunt, mate, and hide on land and usually have heavy shells.

Common usage varies by location. Here is a chart of the basic breakdowns by types of turtles and what they are called in various areas:

	United States	Europe, Australia
Completely terrestrial (tortoises)	tortoise	tortoise
Mostly terrestrial (box turtles)	turtle	tortoise
Semi-aquatic (pond turtles, sliders)	turtle	terrapin
Fully aquatic (fresh water) (snappers, softshells)	turtle	turtle
Fully aquatic (sea water)	turtle or sea turtle	turtle or sea turtle

Special cases: ’Terrapin’- brackish water species. Also used in the southern states for edible turtles. ’Tortoise’ is also used for native fresh-water species in Australia.

So… ALL turtles, terrapins, and turtles can be safely and accurately called ‘turtles’, although ‘chelonian’ is more accurate. When someone says your beloved tortoise is a ‘turtle’, they are technically correct.