Turtles
have been on the earth for more than 200 million years. They evolved
before mammals, birds, crocodiles, snakes, and even lizards.
The
earliest turtles had teeth and could not retract their heads, but
other than this, modern turtles are very similar to their original
ancestors.
Turtles live on every continent except Antarctica.
Turtles will live in almost any climate warm enough to allow them to complete their breeding cycle.
While
most turtles do not tolerate the cold well, the Blanding’s turtle has
been observed swimming under the ice in the Great Lakes region.
Turtles range in size from the 4-inch Bog Turtle to the 1500-pound Leathery Turtle.
North
America contains a large variety of turtle species, but Europe
contains only two species of turtle and three species of tortoise.
The shell of a turtle is made up of 60 different bones all connected together.
Most land tortoises have high, domed carapaces that offer protection from the snapping jaws of terrestrial predators.
Most
turtle species have five toes on each limb with a few exceptions
including the American Box Turtle of the Carolina species that only has
four toes and, in some cases, only three.
Turtles
have good eyesight and an excellent sense of smell. Hearing and sense
of touch are both good and even the shell contains nerve endings.
Some
aquatic turtles can absorb oxygen through the skin on their neck and
cloacal areas allowing them to remain submerged underwater for extended
periods of time and enabling them to hibernate underwater.
Turtles
are one of the oldest and most primitive groups of reptiles and have
outlived many other species. One can only wonder if their unique shell
is responsible for their longevity.
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