Green Sea Turtle

October 20, 2015
Heidi Rockney and Karen Wu
Green Sea Turtle (Chelonia mydas) swimming

Photo: Green Sea Turtle (Chelonia mydas) from Marine Conservation Society

Name: Green Sea Turtle (Chelonia mydas)
Order: Turtles (Testudines)
Family: Sea Turtles (Cheloniidae)

What they look like

  • With a length of 28 to 60 inches and weight of up to 450 pounds, green sea turtles are some of the largest turtles around.
  • Their smooth upper shell can be gray, green, brown, or black and their lower shell is yellowish white.
  • Males are larger than females and have longer tails.

Where they live

  • Green sea turtles are found in subtropical and tropical oceans worldwide, including the Pacific, Atlantic, and Indian oceans.
  • Their preference for warmer waters, those above 20°C, is due to their sensitivity to cold and heat.
  • Males spend their entire lives out at sea, while females only come out of the water to lay eggs.

What they eat

  • Adult green sea turtles are strict plant eaters and spend much of their time eating algae in the ocean or grass in shallow waters.
  • However, young green sea turtles are also able to eat jellyfish, worms, snails, sponges, and crabs.


  • Every 2 to 3 years, females travel to the same beach they were born to lay their eggs.
  • She digs a deep nest using her back legs.
  • Lays 100 to 200 eggs, and covers her nest with sand.
  • The young hatch after about 2 months and head straight for sea.

Cool Biology Facts

  • Some female green sea turtles have been observed digging a fake nest next to their real nest in order to deceive predators who might want to eat the eggs.
  • Green sea turtles have been known to travel 3,000 miles at speeds of up to 15 miles per hour!


  • Green sea turtles are considered an endangered species. Their main threats include loss of nesting habitat due to coastal development and hunting for their meat, hides, and eggs.

Explore more of the Amphibians & Reptiles of Washington or check out All About Amphibians.

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