Movements on land are awkward. Except for occasional basking by both sexes and egg-laying by females, turtles rarely come ashore.
Turtles are among the longest-lived vertebrates.
Although their age is often exaggerated, they probably live 50 to 100 years. The shell, or exoskeleton, of most turtles is composed of bony plates covered with horny shields. The shell of a few species is covered with smooth skin. The green turtle has a smooth, hard, olive or dark brown shell. The leatherback has a smooth leathery skin with prominent longitudinal ridges on its shell.