Get to know the ocean's master navigator

Order: Testudines 

Family: Cheloniidae

GenusChelonia

SpeciesC. mydas

Range: Shallow coastal waters in tropical and temperate regions all over the world. Largest nesting populations found in Costa Rica and Australia

Population: Total population unknown but approximately 85,000 to 90,000 nesting females worldwide

How to spot them: Brown, dark brown, or black shells with much lighter, yellow underside; large, paddle-like flippers; single pair of prefrontal scales between the eyes (unlike two pairs on other sea turtle species); can reach 5 ft. long & 700 lbs.

IUCN Red List Status: Endangered: At very high risk of extinction in the wild

Green sea turtles are drawn to an abundance of food in the western part of the Galápagos archipelago, making them easy for snorkelers to spot. Video by David Pickar aboard the National Geographic Endeavour II in Isabela Island, Galápagos. 

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The sea turtle is one of Earth’s oldest creatures—its distant cousin first popping up in fossils dating back more than 200 million years, when dinosaurs roamed. But despite their long track record, these ancient reptiles face a life fraught with challenges, from the very moment they’re born. It’s estimated that only one of every 1,000 hatchlings will survive to adulthood.

Just two inches long when they break out of their sandy nests, typically at night, baby sea turtles make a mad and dangerous dash to the sea, guided only by the slope of the beach and bright reflections of the moon and stars on the water. Survivors that make it past the numerous obstacles—predators like crabs and birds, disorienting artificial lights, even deep footprints in the sand—swim in a frenzy for up to hundreds of miles. They instinctively know how far to go to reach ocean currents that will carry them to far-flung feeding grounds where they’ll hide out for years, eating and growing.

When mature and ready to mate, at anywhere from 26 to 40 years old, sea turtles leave the feeding grounds where they spend their lives and migrate huge distances—sometimes thousands of miles across entire oceans. Using Earth’s magnetic field like a GPS, they navigate back every three to four years to the exact same beach where they were born. They mate in shallow water, and the females climb ashore to lay their eggs, up to 200 in a single sandy nest. And slow and steady, the adventure begins again.

Discover more facts about the Green Sea Turtle, one of seven sea turtle species.