Green sea turtles are the world’s largest species of hard-shelled sea turtle.
Green sea turtles are the world’s largest species of hard-shelled sea turtle.
Photograph by Richard Carey, Dreamstime

Green Sea Turtle

Green sea turtles are the world’s largest species of hard-shelled sea turtle.

Common Name:
Green Sea Turtle
Scientific Name:
Chelonia mydas
Group Name:
Up to 5 feet
Up to 700 pounds

These turtles are found nesting along the coastline of more than 80 countries, with the largest nesting populations found in Costa Rica and Australia.

Green sea turtles spend most of their lives underwater, where they can rest for up to five hours at a time before coming up for air. When active, they typically alternate between being underwater for a few minutes and coming up to the surface to breathe air for a few seconds. Green sea turtles are also known to sunbathe on land.

Unlike most other sea turtles, adult green sea turtles eat a primarily plant-based diet consisting of seaweed and sea grass. Scientists believe these green foods give the sea turtle’s fat its green color. The shell of the green sea turtle is usually shades of a brown or olive color.

Similar to other sea turtles, green sea turtles migrate long distances between their feeding grounds and their nesting sites, with recorded distances longer than 1,615 miles (2,600 kilometers). They have strong paddlelike flippers that help propel them through the water.

Female green sea turtles leave the water in order to lay eggs on the beach and will choose the same nesting spot as where they were born. A female will dig out a nest with her flippers and lay a clutch of about 115 eggs. Then she’ll cover the eggs with sand and return to the sea. After about two months, the babies will use a special “egg tooth” to break their shells and hatch from their eggs.

The first few years of a green sea turtle’s life are spent floating at sea, where they feed on plankton. As they grow older, the turtles move to shallow waters along the coast, such as bays and lagoons, where they find sea grass to eat.

Adult green sea turtles face many threats, primarily from humans, including injuries from boat propellers, being caught in fishing nets, pollution, and poaching. Newly hatched sea turtles are also at risk of being hunted by animals such as birds, crabs, and raccoons as they move from their nests out to the sea.