Turtles apply to chelonians that live in or around water. Sea turtles, for example, never leave the ocean except to lay their eggs. Other turtles are more or less aquatic, depending on their species.

The sliders, mud, bog, and leaf turtles are all found close to fresh water. Terrapins are aquatic turtles that people frequently eat. Many terrapins live in and close to brackish salt water. Box turtles are primarily terrestrial (land roving) but are almost always found within walking distance of water.

The term tortoise refers to chelonians that live on land and rarely venture into water except to drink or bathe. Tortoises range in size from tiny little guys weighing less than 1 pound to gigantic, weighing over 600 (or more) pounds.

Size aside, tortoises have many things in common. They are primarily herbivores (plant eaters), although many will scavenge, given the chance. Tortoises also usually have hard shells, often with high domes, to help protect against predators.