Monday, December 1, 2008

Sea Turtle

Sea turtles are turtles that you can found in all the oceans except the Arctic Ocean. This is the one of sea animal that I like.

The East Pacific subpopulation of the green turtle was previously classified as a separate species, the black turtle, but DNA evidence indicates that it is not evolutionarily distinct from the green turtle. There are seven living species of sea turtles: flatback, green sea turtle, hawksbill, Kemp's Ridley, leatherback, loggerhead and olive ridley.

They spend almost all lives submerged but must breathe air for the oxygen needed to meet the demands of vigorous activity. With a single explosive exhalation and rapid inhalation, sea turtles can quickly replace the air in their lungs. The lungs are adapted to permit a rapid exchange of oxygen and to prevent gasses from being trapped during deep dives. The blood of sea turtles can deliver oxygen efficiently to body tissues even at the pressures encountered during diving.

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