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Green Sea Turtle Facts (Chelonia Mydas)

The Green Sea Turtle can be found in tropical marine waters and have been seen nesting around western and northern Australia, Costa Rica, Europa and nearby islands in the Mozambique Channel, Pacific Mexico, Oman, Pakistan, Philippines, Sabah, and Sarawak.

Their population in a good year can range anywhere from 10,000 nesting females to 80,000 nesting females in stable areas. Females lay about 100 to 120 eggs in each clutch of three.

Keep on reading to learn lots more below!

Green sea turtle facts

  • Scientific Name: Chelonia Mydas
  • Size: Average nesting female carapace (shell) is about 32 to 43 inches (80 to 110 cm)
  • Weight: Average nesting female is about 243 to 408 pounds (110 to 185 kg)
  • Habitat: These turtles favour staying in the ocean while young and as adults during feeding. They tend to stay close to shore for mating and nesting.
  • Food: The species is primarily herbivore. The diet consists of marine plants like seagrass and seaweeds.
  • There’s been a rapid decline in numbers for the last 200 years. It is currently listed as Endangered on IUCN. The current estimate of total nesting females is about 80,000.

What is the Green sea turtle?

Belonging to the larger types of turtles, it gets its name for its solid layer of green coloured fat underneath its shell. Scientists say this is probably because of their vegetarian diet.  This type of marine turtle is also the easiest to identify. It has only one pair of scales in front of the eyes. Other sea turtles have two pairs of prefrontal scales.

There are actually two types of Green sea turtles. The Atlantic Green turtle lives around the shores of Europe and North America. The Eastern Pacific Green turtle resides in Alaska and Chile’s coastal waters.

Some interesting Green sea turtle facts

Green sea turtle_swimming_over_coral_reefs_in_Kona
  • It can live up to 80 years in the wild.
  • Babies grow a special tooth which they use to break out of their shells when it is time to hatch.
  • In July 2012, more than 105 Green sea turtles were found dying or dead on the beaches of Upstart Bay, Townsville.
  • A large population lives and nests around the Great Barrier Reef. Divers often sight one of these gliding by.
  • It is the only herbivorous type among other marine turtles.
  • The largest green turtle measured 5 feet long and weighed 871 pounds or 395 kg.

Where do Green sea turtles live?

Green sea turtles are drawn to temperate and tropical waters. During their first few years, Green sea turtles float in the open ocean and feed on planktons. Older ones look towards shallow waters along coastlines to find sea grass for food. You’ll see them living in bays or lagoons. One of the largest nesting grounds can be visited in Raine Island, Australia. The have also been seen in San Diego Bay in San Diego, CA.


Green sea turtles are one of the world’s largest turtle species. Their shell or carapace is strong, covering most of their bodies. Only the head and four flippers remain exposed. The shape is tear-dropped and can feature different shades along the lines of dark brown, olive, green, black, and yellow.


You’ll find them near the coastline. They stay in bays and safe shores. They choose sections with beds of seagrass, their preferred food. They do swim ashore to enjoy bathing in the sun.


Green sea turtles also migrate long distances.  It’s because they breed  along the beaches where they were born. They make trips from feeding grounds to their mating and nesting sites. Females make this trip back to their natal beach every two years while males may make an annual journey. Data shows that these turtles can cover more than 2,600 kilometres of travel. Some Green sea turtles from the Western Pacific travel to Papua New Guinea, Caledonia, and Solomon Islands to find feeding spots.



Like other marine turtles, the Green sea turtle has a good sense of smell. It easily locates food even in cloudy waters. The nose also helps locate land and helps guide females back to their home nesting beach. It sees clearly in the water but can be nearsighted on land. As for the sense of hearing, studies show that sea turtles hear better on low frequencies. They depend more on vibrations for calculating distances and the presence of objects and other creatures at sea.

What do Green sea turtles eat?

The food choices of Green sea turtles change throughout its life. As a hatchling, they eat small crustaceans, worms, other marine insects, algae and sea grass. When they reach 8 to 10 inches long, they mainly stick to algae, sea grass and seaweed for food. Adult Green sea turtles switch to being herbivorous when they’ve developed finely serrated jaws that effectively tear sea vegetation.



Like other sea turtles, the Green sea turtle is a strong swimmer who navigates well underwater. Recorded speeds are fastest at 35 km/h with a cruising speed of 3 km/hr. Because of their large size, their flippers perform as paddle-like propellers, steering and moving them at quick and far-reaching lengths.

Laying eggs

Green sea turtles nest in more than 80 countries worldwide. The largest nesting beaches are in Australia and Costa Rica. Mating happens in shallow waters offshore. Then, females crawl on the sandy beach towards their nesting spot. Typical nest yields 115 eggs. She covers them with sand and goes back to sea. The eggs incubate for 60 days in a nest chamber which situates 1 metre underground.


Nesting season is at 2-year intervals, sometimes more.  Some observe that female Green sea turtles may nest every five to eight years. And on average, females will nest for two (up to five) each season. Arribadas or mass nesting seasons may produce enormous clutches or large amounts of eggs; but some conservatively estimate that only 1 in 10,000 hatchlings will survive and grow to be adults.

What are the predators they face?

Green sea turtles are most vulnerable as hatchlings. Making the laborious crawl towards the waters can lead to death since predatory birds, wild dogs, lizards, and crabs may be lurking nearby just waiting to plunge in and grab these little ones.

Why are Green sea turtles endangered?

They are endangered for many reasons. Hunters prey on them for their shell, meat, and eggs. Fishing nets, even discarded fishing gear, catch unfortunate ones who drown in the equipment. Some get hit by incoming boats. Nesting beaches also get damaged or destroyed by commercial improvements.

Pollution on nesting grounds and in the water is a prevailing problem, poisoning them and their habitats. Others die from getting entrapped or from ingesting marine plastics. Research indicate that Green sea turtles that live around urban and farming areas are at health risk for viruses and weakened immune systems due to industrial and agricultural chemicals that are released in those areas.

Climate change is also a factor to endangerment. Marine turtles are influenced by temperatures when it comes to sex determination. Hence, the problem of global warming is likely changing the ratios of male to female hatchlings.

Catching Green Sea Turtles (Video)

References: Groombridge, B. 1982. The IUCN Amphibia Reptilia Red Data Book:Testudines, Crocodylia, Rhynchocephalia. IUCN, SwitzerlandPhoto courtesy of NOAA

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