How many species of sea turtles exist today? Seven species exist today: the flatback, green, hawksbill, leatherback, loggerhead, Kemp's ridley, and olive ridley turtles.
Six of these species belong to the family Cheloniidae, which includes the hard-shelled turtles. The leatherback is the exception: it is the only living member of the family Dermochelyidae and has a flexible, leathery shell rather than the hard shell typical of other sea turtles.
Sea turtles are reptiles, so they must breathe air even though they spend most of their lives in the ocean. Females return to land to lay eggs, often nesting on or near the beaches where they hatched. Hatchlings then cross the beach and enter the sea, facing heavy losses to predators and environmental hazards.
The seven species occupy different ranges and habitats. The flatback is concentrated around Australia and nearby waters, while the leatherback has the broadest oceanic range. The number seven refers to living species, not the many extinct marine turtles known from the fossil record.