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Amphibionics 07 3/24/03 9:13 AM Page 271
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Turtletron:

Build Your Own

Robotic Turtle

Turtles and Tortoises

There are more than 270 living species of turtles and tortoises.
These creatures are found in terrestrial, fresh water, and marine
habitats, and in both temperate and tropical regions. The term
“turtle” usually refers to a freshwater or marine species, while the
term “tortoise” is normally used for terrestrial species. “Terrapin”
is the informal name for a freshwater turtle.

Turtles and tortoises belong to the order Testudines, which is divid-
ed into two suborders. The primitive sideneck turtles (suborder
Pleurodira) cannot fully retract their long necks. When they are at
rest, they must lay their heads sideways along the inside of their
shells. All of the 70 or so species of sideneck turtles live in fresh-
water. The more advanced straightneck turtles (suborder
Cryptodira) are a much larger group that lives on land and in water.
They are able to withdraw their heads completely into their shells.
Turtles and tortoises vary greatly in size, from the tiny Speckled
Padloper, 2-1/2 inches long, to the massive Leatherback Sea
Turtle, which can reach up to 6 feet in length.

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