This is my Turtle 
Thomas!
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Thomas the Turtle
Terrapin, common name sometimes used for any freshwater turtle, but more accurately restricted to the diamondback, native to the salt marshes of the eastern United States coastal regions from Massachusetts to Texas. The diamondback is named for the concentric, diamond-shaped grooves and ridges in the shields of the upper shell. Females are much larger than males and may have shells 15 to 23 cm (6 to 9 in) in length; the shells of males are only 10 to 14 cm (4 to 5.5 in) in length. The skin on the limbs and neck is usually pale with many dark spots. The diamondback feeds on mollusks, crustaceans, aquatic insects, and fish. The turtle's flesh is considered a great delicacy and the species was at one time threatened with extinction. It is now protected and has made a modest comeback.
Turtles breathe air with lungs, as do other reptiles and all land-living vertebrates. Since turtle ribs are part of their shell, turtles cannot move their ribs in and out to expand or deflate their lungs. Instead, turtles alternately expand and contract various groups of muscles, including those in their abdomen and above their front and hind legs, to change the amount of space within the shell. When these muscles expand, less space is available and the lungs are compressed, permitting the turtle to exhale. A turtle takes in air as these muscles contract to provide more space into which the lungs can expand. Many aquatic turtles remain submerged in water for periods of several hours to several days-and for many months during winter hibernation. Many turtles are able to take in oxygen from water through the linings of the mouth, throat, and an internal chamber called the cloaca, as well as through the skin. However, when they are active, aquatic turtles need to rise to the surface periodically to breathe air with their lungs.
Like most reptiles, except for crocodiles and their close relatives, turtles have a heart with three chambers. A turtle's heart operates almost as if it had four chambers, however, because one of its chambers, called the ventricle, has an incomplete divider, or partition. This divider helps prevent the blood that has received oxygen from the lungs and is ready to circulate through the turtle's body from mixing with blood that is depleted in oxygen and needs to travel to the lungs for a fresh supply.
In a turtle's digestive system, food passes from a turtle's mouth through a tubelike esophagus to the stomach, where digestion begins. Food passes from the stomach into the intestine, where nutrients can be absorbed into the bloodstream. Wastes from the intestine are emptied into the cloaca, from which the wastes leave the turtle's body. Turtles also have a urinary system, which filters waste products from the blood and excretes them through the cloaca.
Turtles have a central nervous system and a well-developed brain. They have keen senses that they use to interpret their world. Most turtles have sharp vision and can recognize patterns and colors. The eyes of sea turtles are adapted for seeing underwater, but they can see only short distances when they are on land. Most turtles, including sea turtles, have a good sense of smell. Both the shells and the skin of turtles are sensitive to touch. Turtles' ability to hear sounds that travel through the air is limited to low frequencies, but they can perceive vibrations transmitted through the ground or water.
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