Sea Turtles and You

Sea Turtle Natural History

Sea Turtles and You Home




















































Sea turtle are ancient reptiles that have changed little over their 150-200 million-year history on the Earth. The earliest sea turtles watched the Age of the Dinosaurs come and go. Today there are seven or eight species depending on different scientists. The species include:

1) Loggerhead (Caretta caretta)
2) Kemp’s Ridley (Lepidochelys kempi) 
3) Olive Ridley (Lepidochelys olivacea)
4) Leatherback (Dermochelys coriacea)
5) Hawksbill (Eretmochelys imbricata)
6) Flatback (Natador depressa) 
7) Green (Chelonia Mydas) which is sometimes divided into two species,
a. Green
b. Pacific Green, also known as Black (Chelonia agassizii)

Although all of these species are distinct in their anatomy, physiology, diet, and behavior, these giant reptiles all share several characteristics.

Sea Turtles:
· May live to be 100 years old. Turtles are the oldest living vertebrate animals.
· Do not have teeth, but have powerful jaws with sharp edges like birds.
· Have been on Earth for 150 to 200 million years, which is before the time of dinosaurs.
· Are adapted to living in the marine environment by having flippers instead of legs and a streamlined body shape. They are fast and graceful in the water, but slow and clumsy on land.
· Must breathe air like all reptiles (and humans), but can hold their breath for long periods of time and can dive very deep.
· Are the largest reptiles in the world by weight. A giant leatherback that washed up along the Coast of Wales weighed over 2000 pounds and measured 9˝ feet from head to tail. The Ridleys are about two to three feet long and weigh up to 100 pounds.
· Migrate thousands of miles in the course of a year, moving between nesting and feeding grounds. An Olive Ridley tagged in Suriname, South America, traveled 1900 miles against the prevailing current in 23 days.
· Nest singly (most species), but the Ridley species have a unique mass-nesting strategy called the “arribada” which is Spanish for arrival. Anywhere from 500 to 300,000 female Ridleys will go up on the beach within a couple of days of each other to lay their eggs. This makes it impossible for a natural predator to take all of the eggs and increases the odds of hatchling survival.
· Have temperature-dependent gender determination. The hatchling will be male if the eggs incubate at a cool temperature or female if the eggs incubate at a warm temperature.

Female Sea Turtles:
· May take 20 to 50 years to reach sexual maturity, but return to the very same beach where they were born to lay their eggs.
· Spend virtually their entire lives at sea, mate offshore, and return to only land to lay their eggs.
· Carefully dig a deep hole for a nest and lay up to 180 eggs at a time on sandy beaches. The eggs must be on land, so the embryos can breathe air through the eggshell.
· Provide no maternal care to the eggs once they are laid and buried. The nest site is camouflaged to protect the eggs from predators.

Sea turtles are also an important part of the marine ecosystem. Sea turtles are connected to the food web in the ocean by the prey they eat and the predators that eat them. Sea turtles eat jellyfish, sponges, tunicates, algae, sea grasses, and crustaceans. The only natural predators of adult sea turtles at sea are sharks, Orcas whales, and humans. 
Nesting females are sometimes attacked and eaten by jaguars, tigers, and hyenas. The high-protein eggs that are laid in great numbers on some nesting beaches provide food for a myriad of animals including raccoons, coatis, coyotes, jackals, dingoes, mongooses, foxes, opossums, vultures, crows, varanid lizards, snakes, crabs, flies, and ants.

If the eggs survive to become hatchlings, most of these same predators eat young turtles and the list grows to include all kinds of fish including shards, groupers, and cod. Birds that act as predators to the hatchlings are herons, egrets, frigate birds, and hawks.

Sea turtles interact with their environment in ways that are not obvious at first glance. For instance, sea turtles interact with:

· Pelagic (open ocean) sea birds. These birds spend the majority of their lives flying out over the open ocean, and from time to time must rest. Sometimes they rest on top of the water, vulnerable to predators such as sharks, unless there is another object available to them. These birds are often seen resting on the backs of sea turtles as the turtles cruise the open ocean. This is a form of mutualism, where two different species have an ongoing relationship. It is not well known whether this particular relationship is communal (no effect on the turtles) or whether it is mutualistic (both the sea turtle and the sea bird gain some benefit).
· Remora fish that attach onto turtles for a free ride.
· Barnacles and algae that attach to the shells of sea turtles and travel the ocean.
· Small fish that set up “cleaner stations” where sea turtles line up to have algae and other small organisms nibbled off their shell.
· Micro fauna on the beach. These tiny animals within the sand depend on both the turtles’ disturbance of the sand and the eggs within the sand for structuring of the community. The bacteria in the sand feed on rotting turtle eggs that did not hatch when the others did.

Sea turtles also interact with the environment and humans in 
other ways:
· Shrimp trawlers catch an estimated 150,000 turtles each year as a by catch in their nets.
· Humans collect thousands of sea turtle eggs from the nesting beaches.
· Poachers take hundreds of thousands of sea turtle eggs to sell at marketplaces in cities far away from beaches.
· Hotels and other developments destroy nesting beaches.
· Lights near nesting beaches disorient hatchlings. They do not crawl toward the sea, and they die in the heat.
· Plastic bags in the water look like jellyfish to turtles. The bags are caught in their intestines.

Source: Sea Turtle Restoration Project






















































South Walton Turtle Watch

Florida Sea Turtle Grants Program

Van R. Butler Elementary School


Last Updated: 3/06