Green Sea Turtle

Genus: Chelonia
Species: mydas

Green sea turtles are rarely seen on land, but when they do make it to shore, they can stop traffic – beach traffic that is. Green sea turtles are an endangered species with drastically reduced population sizes. Females use beaches throughout the southeast United States, Puerto Rico, the Virgin Islands and Hawaii to lay their eggs.

Although it might seem like an inconvenience to have a stretch of beach shut down to make way for turtles, the alternative is much more devastating. These majestic giants of the ocean depend on our support and protection to ensure that they do not go extinct. So remember on your next summer vacation to make way for the turtles, because they need the beach much more than we do.

Baby sea turtle

Description:  A green sea turtle's shell (called a carapace) is the largest and most noticeable part of the animal. The shell covers most of the body, except for the flippers and head. Despite its name, a green sea turtle's shell is not always green. The shell can be a blend of different colors including, brown, dark olive, gray or black. The shell is also smooth and heart-shaped. The underside of the shell (called the plastron) is a yellowish-white color.

Green sea turtles actually received their colorful name from the color of their subdermal (underneath the skin) body fat.    

Unlike many other turtle species, sea turtles cannot retract their head into their shell. The head has brown and yellow markings.  

Green sea turtles have paddle-like limbs called flippers whcih allow the turtle to move quickly and easily through the water. 


Size:  Green sea turtles are really big!  They can grow to 3 - 4 feet (91 - 122 cm) in length. They are very dense and heavy animals. An adult green sea turtle can weigh upwards of 300 - 350 pounds (136 - 159 kg)!  Despite their size, they are still not the world's largest sea turtles - that title belongs to the leatherback sea turtle!


Green Sea Turtle

Diet:  Adult green sea turtles are herbivores. The jaw is serrated to help the turtle easily chew their primary food source -- seagrasses and algae.

Juvenile green sea turtles are omnivores. They eat a wide variety of plant and animal life, including insects, crustaceans, seagrasses and worms. 


Typical Lifespan:  Green sea turtles live very long lives. It takes at least 20 - 50 years to reach sexual maturity and a healthy individual can expect to live 80-100 years or even more! A lot is still unknown about the life history of green sea turtles. 


Habitat:  Green sea turtles have ocean water habitats and nesting habitats. Once a green sea turtle hatches and heads into ocean waters, it rarely returns to land. Instead, it feeds on off-shore plant blooms around islands and beaches.

Green sea turtles stay in shallow waters off-shore until the breeding season. They will travel long distances, even across oceans, to return to their preferred breeding site. In the nesting season females emerge onto warm beaches around the world to lay their eggs.


Range:   Green sea turtles are found around the world in warm subtropical and tropical ocean waters, and nesting occurs in over 80 different countries. There are populations with different colorings and markings in the Atlantic, Indian and Pacific Oceans. 

In the United States, you are most likely to see green sea turtles on the Hawaiian Islands, Puerto Rico, the Virgin Islands and the east coast of Florida. Less frequent nesting also occurs on the Atlantic coast in Georgia, South Carolina and North Carolina.


Nesting Green Sea Turtle

Life History and Reproduction:  The breeding season occurs in late spring and early summer. The males arrive in off-shore waters first and wait for the females to come to the beaches. Adult males can breed every year, but females only breed every 3-4 years or so.

A few weeks after mating, a female green sea turtle arrives on the beach and digs a hole in the ground for her eggs. Inside the hole, she lays over 75 - 200 eggs and then covers the hole with sand. At this point, her role is complete and she leaves her eggs to fend for themselves.  A female green sea turtle can lay several clutches of eggs before she leaves the nesting grounds.

After approximately two months, the eggs hatch and the hatchlings make their way to the water. The newly hatched green sea turtles are very susceptible to predators, exposure and losing their way. Birds, mammals and other predators love feasting on the young turtles.  One of the greatest threats to hatchlings is light pollution near beach nesting sites.  The light from buildings and homes confuses the young turtles so that they crawl towards the light and not the ocean.

For green sea turtle hatchlings that reach the water, it will be at least 10-25 years before they themselves can breed. Females prefer to lay their eggs at their own nesting beach. Every 3-4 years when the females breed, they make a long migration back to their natal beach.


Threats to Green Sea Turtles:

 

Conservation Efforts:

  • Green sea turtles are protected by national and state laws, as well as international treaties. They are listed on the Endangered Species List -- listed as endangered in the state of Florida and as threatened in other state coastal areas where they are found.

  • Bycatch of green sea turtles (accidental capture by commercial and sport fishermen) is being reduced by fishing gear modifications (i.e. use of TED’s or turtle exclusion devices), changes to fishing practices and closures of certain areas to fishing during nesting and hatching seasons.

  • Designation of critical habitat areas in coastal waters around parts of Puerto Rico.

  • Encourage use of low pressure sodium lighting along beach nesting areas

  • Regular monitoring of green sea turtle populations by NOAA's National Marine Fisheries Service (NMFS).

 

National Wildlife Magazine Articles:

The Return of Kauila

 

Sources:

Fish and Wildlife Research Institute

U.S. Fish and Wildlife Service

NOAA Fisheries Office of Protected Resources

U.S. Fish and Wildlife Service

University of Michigan's Animal Diversity Web

NatureServe Explorer

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