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Tuesday, 9 December 2008

Biology: 5 reef animals

2. Green Sea Turtle



Green sea turtles are a marine turtles of the sea turtle family called Cheloniidae. The green sea turtle's Latin or Scientific name is Chelonia mydas. The are cold blooded, breath oxygen and have green skin cover in scales. The are named by the color of there skin and body fat, not there shell which is normally brown or olive color.

The sea turtle's body is wonderfully adapted to life in the ocean. Their shell is lighter and more streamlined than that of land turtles. They also have flipers instead of feet to make swiming easier. When sleeping or resting, which usually occurs at night, adult sea turtles can remain underwater for more than 2 hours without breathing. This is due to the fact that turtles are capable of containing higher concentrations of carbon dioxide in their blood than most other air-breathing animals, enabling them to use their oxygen very efficiently.they also hava a salt gland behind each eye. The salt glands help sea turtles to maintain a healthy water balance by shedding large "tears" of excess salt.

Green sea turtles are one of the largest sea turtles and can weigh as much as 700 pounds (317.5 kilograms). Their proportionally small head, which is nonretractable, extends from a heart-shaped carapace that measures up to 5 feet (1.5 meters). Males are slightly larger than females and have a longer tail.

Adults eat sea grass and algea. Junvenles will aslo eat crabs, jellyfish, and sponges.

While most sea turtles warm themselves by swimming close to the surface of shallow waters, the Eastern Pacific green turtle will take to land to bask in the sun. Occasionally seen sunbathing alongside seals and albatrosses, it is one of the few marine turtles known to leave the water other than at nesting times.

Green sea turtles have long migrations to feeding and nesting areas. The life span of sea turtles in not known. Hawaiian green sea turtles seem to grow very slowly in the wild, usually taking between 10 and 50 years to reach sexual maturity - 25 years is the average. Their long period of maturation helps to explain why it takes sea turtles so many years to recover from a substantial population decline. Male and female green sea turtles look virtually alike until they mature. Then, the two sexes are easy to tell apart: the males have long, thick tails, while the females have short, stubby ones. This is an example of sexual dimorphism, or, the ability to differentiate between the sexes of a particular species on the basis of external body characteristics.

Green sea turtles nest only at night. A female crawls on land and digs a nest, lays her eggs in it and and covers them up.

Green sea turtles have been hunted for there, shells, eggs, meat, fat, and oils. Litter and other marine debris can prove deadly to sea turtles when they entangle the turtles or are mistaken for food and ingested. Sea turtle nesting beaches are lost each year to coastal development, leaving the females without a familiar place to lay their eggs. A fairly recent phenomenon recorded in Hawaii's population of green sea turtles as well as in populations off the coast of Florida is the presence of a disease called fibropapilloma.

Green turtles are listed as an endangered species, and a subpopulation in the Mediterranean is listed as critically endangered.

Sources:
hawaiimarinelife.com
www.earthtrust.org
National Geogrphic

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I am a grade nine student living in Mexico. This is my home school education blog. I post the things I learned during the week on this blog. I hope you can learn things from this too.


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