Sea Turtles

Sea Turtles

Reptiles

SCIENTIFIC CLASSIFICATION

COMMON NAME: sea turtle
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Reptilia
ORDER: Testudines (somes sources cite as Chelonia)
FAMILY: Cheloniidae - with scutes
Dermochelyidae - scuteless
GENUS SPECIES: There are 7 species of sea turtles:

Green (Chelonia mydas): 2 subspecies
  ° black or Eastern Pacific green turtle (Chelonia mydas agassizii)
  ° green (Chelonia mydas mydas)
  loggerhead (Caretta caretta)
  Kemp’s ridley (Lepidochelys kempii)
  olive ridley (Lepidochelys olivacea)
  hawksbill (Eretmochelys imbricata)
  flatback (Natator depressus)
  leatherback (Dermochelys coriacea)

FAST FACTS

DESCRIPTION: Sea turtles are characterized by a long, streamlined shell. Depending on the species, sea turtles color range can be olive-green, yellow, greenish-brown, reddish-brown, or black. Limbs and flippers are adapted for swimming. Adult male and female sea turtles are equal in size.
MALE The tail may extend beyond the hind flippers. The claws on the foreflippers of sea turtle males (except leatherbacks) are elongated and curved, which may help them grasp a female's shell during mating.
SIZE: Most sea turtles are 53-114 cm (21-45 in.). The largest species, the leatherback, can reach 1.2-1.9 m (3.9-6.2 ft.). 2.9 m (9.5 ft.) was the largest leatherback recorded. Significant differences in size are not exhibited between the sexes.
WEIGHT: 27 to 186 kg (60-410 lb.) for smaller species.

Leatherbacks can weigh 200 to 660 kg (441-1,454 lb.), with reported weights up to 870 kg (1,918 lb.).
DIET: Sea turtles may be carnivorous (meat eating), herbivorous (plant eating), or omnivorous (eating both meat and plants).
INCUBATION: 45-70 days
CLUTCH SIZE 50-200 eggs
1-9 clutches per season
BREEDING PERIOD Generally, the nesting season occurs during the warmest months of the year.
SEXUAL MATURITY: As early as 3 years in hawksbills, to 12-30 years in loggerheads, and 20-50 years in green sea turtles.
LIFE SPAN: Up to 80 years
RANGE: Warm and temperate seas throughout the world
HABITAT: Shallow coastal waters, bays, lagoons, estuaries and occasionally the open ocean
POPULATION: GLOBAL Unknown
  REGIONAL Unknown
STATUS: IUCN The hawksbill and Kemp's ridley sea turtles are listed as critically endangered.

The green, loggerhead, and olive ridley sea turtles are all listed as endangered.
CITES The green, loggerhead, and olive ridley sea turtles are all listed as endangered.
USFWS The hawksbill, Kemp's ridley, leatherback, populations of green sea turtles (along Florida and the Pacific coast of Mexico), and breeding populations of olive ridleys (on the Pacific coast of Mexico) are listed as endangered.

The loggerhead, green (except the populations listed above), and olive ridley (except the populations listed above) sea turtles are listed as threatened.

FUN FACTS

1. Most scientists recognize eight species of these marine reptiles. Experts can identify each by the number and pattern of scutes (horny plates) on the carapace (top shell).
2. A leatherback turtle is covered with leathery skin, not scutes (horny plates) like other sea turtles. It is the only marine turtle whose backbone is not attached to the inside of its shell.
3. Sea turtles are found in tropical and temperate seas throughout the world. Adults of most species inhabit shallow coastal waters. Some species migrate great distances form winter feeding grounds to summer nesting areas.
4. Typically, the only time sea turtles leave the sea is when females haul out to lay eggs. On some uninhabited or sparsely-inhabited beaches, turtles of either sex have been observed basking on land.
5. Once sexually mature, female sea turtles will typically return to the beach area from which they originally hatched. Season after season, the females ascend their ancestral beach to deposit their own clutch. A female turtle digs a pit in the sand using her hind flippers, and deposits dozens of eggs the size of ping pong balls. These eggs then incubate beneath the sand from roughly 1.5 to 2.5 months, at the end of which time the eggs hatch in approximate unison. The newly hatched turtles attempt to scramble to the surface, down the beach, and past the shoreline - with the survivors continuing the cycle of birth, growth, and return.
6. During the first year after hatching, many species of sea turtles are rarely seen. This first year is known as the "lost year". Researchers generally agree that most hatchlings spend their first few years living an oceanic existence before appearing in coastal areas. Although the migratory patterns of the young turtles during the first year has long been a puzzle, most researchers believe that they ride prevailing surface currents, situating themselves in floating seaweed where they are can find food.
7. Diets vary greatly among sea turtle species. Green and black sea turtles feed on seagrasses and algae. Loggerheads' and ridleys' strong jaws can crush crabs, shrimps, and molluscs. Leatherbacks prey only on jellyfish and other soft-bodied animals.
8. The green sea turtle gets its name from the color of its body fat.
9. A sea turtle cannot retract its limbs, head or neck under its shell like a land turtle. The shell adaptations necessary for retractile limbs would impede rapid swimming.
10. Sea turtles' long, paddlelike flippers are adapted to locomotion in the water. Sea turtles are strong swimmers and divers.
11. Green sea turtles can stay under water for as long as five hours. Their heart rate slows to conserve oxygen: nine minutes may elapse between heartbeats.
12. All eight sea turtle species are listed as either endangered or threatened. Despite several management measures to preserve sea turtles, their future is still in question, due to a number of natural and human-induced factors.
13. For more information about sea turtles, explore the SEA TURTLE INFOBOOK.

ECOLOGY AND CONSERVATION

Sea turtles are vulnerable to natural and human impacts. Hurricanes can impact sea turtle nesting success. Coastal development and disturbances, such as noise and activity on beaches, leave little room for sea turtle nesting areas. Artificial lighting on beaches can confuse nocturnal nesting sea turtles as they may mistake the lighting for daytime and return to sea without nesting. Hatchlings are also confused by artificial lighting, including street and city lights, causing them to head away from the ocean and toward parking lots and city streets. Pollution, such as plastic bags resembling jellyfish, can also cause sea turtle deaths.

Sea turtles are also hunted, illegally in the U.S and legally in some countries, for their meat and shells, which are used to make combs, eyeglass frames, aphrodisiacs, and curios. Some people illegally collect turtle eggs for food and for their alleged aphrodisiac effect. The fat of green sea turtles, boiled with cartilage, made a popular soup called calipee, which led to the decline in green sea turtle population numbers.

The Endangered Species Act of 1973 (ESA) seeks to stop the extinction of wild animals and plants in the United States, other nations, and at sea. All sea turtles, except the flatback, are listed as threatened or endangered on the U.S. Endangered and Threatened Wildlife and Plants List. It is illegal to harm, or in any way interfere with, a sea turtle or its eggs.

BIBLIOGRAPHY

Berger, M. Look Out for Turtles. New York: HarperCollins Publishers, 1992.

Jay, L. A. Our Wild World: Sea Turtles. Minnetonka, MN: NorthWord Press, 2000.

Ripple, J. Sea Turtles. Stillwater: Voyageur Press, Inc., 1996.