A division of reptiles called chelonia includes turtles, tortoises and terrapins. For the most part, the difference between a turtle and a tortoise is more of a matter of semantics than a strict scientific separation. Colloquially, both biologists and laypeople use the word “turtle” to mean all chelonians. In general, the reptiles referred to as turtles live in or near the water and have adapted to swim by holding their breath underwater. The reptiles referred to as tortoises typically live primarily in arid regions and are built for storing their own water supply and walking on sandy ground.
From a biological perspective, a tortoise is a kind of a turtle, but not all turtles are tortoises. Tortoises occupy their own taxonomic family, called testudinidae. All types of land and aquatic turtles come in a wide range of sizes, colors and shapes. Sometimes, the name “terrapin” is used to refer to an animal that falls somewhere between a turtle and a tortoise. Terrapins live in swampy areas or begin life underwater and eventually move to dry land