Sea Turtles 101

Find out about sea turtles' oldest known ancestor, how certain adaptations may have helped the reptiles survive, and the conservation efforts being made to save them.
Common Name:
Sea Turtles
Scientific Name:
Cheloniidae, Dermochelyidae
Diet:
Omnivore
Average Life Span:
unknown
Size:
2 feet to 7 feet long
Weight:
70 to 1500 pounds
Current Population Trend:
Decreasing

Six of the seven species of sea turtles that swim the planet’s waters—leatherback, loggerhead, Kemp’s ridley, green, olive ridley, and hawksbill—are found in every ocean except the Arctic and Antarctic. The seventh, the flatback, lives only in the waters around Australia.

The leatherback is the largest sea turtle and can weigh a whopping 2,000 pounds. It’s also the only sea turtle that doesn’t have a hard, bony shell. Its carapace is somewhat flexible and almost rubbery to the touch. The shells of other sea turtles are made of thick plates called scutes.

A critically endangered hawksbill sea turtle hatchling paddles away from shore in Cuba.
A critically endangered hawksbill sea turtle hatchling paddles away from shore in Cuba.
Photograph by David Doubilet, Nat Geo Image Collection

Turtle journeys

Sea turtles make incredibly long migrations between feeding and breeding areas. The leatherback travels an average of 3,700 miles each way. Sea turtles mate at sea, then come ashore on beaches to lay their eggs. Females dig a hole in the sand, then deposit their clutch of eggs (up to 100, in the leatherback’s case), cover it back up, then return to the sea.

After about 60 days, the eggs hatch and tiny hatchlings make their way from the nest to the water at night, often a deadly ordeal as seabirds, crabs, and other predators prey on the young turtles. Another threat comes from coastal development. Natural light at the horizon guides the hatchings to the ocean. Lights from hotels, homes, and other buildings can confuse the turtles into heading the wrong way.

Extreme threats

Six of the seven sea turtle species are classified as threatened, endangered, or critically endangered, due largely to human impact in the form of hunting, bycatch in fishing nets, pollution, and climate change. Climate change affects the turtles by warming the temperature of the sand that sea turtle eggs are laid in, which in turn affects the outcome of the hatchlings’ sex.

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet