Most scientists recognize eight species of these marine reptiles. Males and females are about the same size. Sea turtles are found in tropical and temperate seas throughout the world. Adults of most species inhabit shallow coastal waters.
Some species migrate great distances form winter feeding grounds to summer nesting areas.
Sea turtles are strong swimmers and divers. Green sea turtles can stay under water as long as five hours. To conserve oxygen, their hearts can slow to one beat every nine minutes. Diets vary greatly among sea turtle species. Green and black sea turtles feed on seagrasses and algae.