Nature Bulletin No. 157 May 29, 1948
Forest Preserve District of Cook County
William N. Erickson, President
Roberts Mann, Supt. of Conservation
Turtles are four-legged reptiles that originated before the dinosaurs
appeared, some 175 million years ago. The distinguishing feature of
the turtle is its shell, varying in shape and markings with the different
species: an arched upper shell grown fast to the backbone, and a flat
lower shell grown fast to the breastbone, the two connected on either
side by a bony bridge. In some species, like the box turtles, the lower
shell is hinged, enabling the animal to completely conceal its head, tail
and limbs by closing the two shells together.
Most turtles live in water all or part of the time, but all of them lay
their eggs on land, and neither the nest nor the young is attended by
the parents. Each species has its own method of nest construction,
using the hind legs to dig a hole in the ground, but the eggs are
covered and left to be hatched by the heat of the sun. The eggs are
relished by many animals such as skunks and squirrels; the young,
before their armor hardens, are devoured by birds, mammals, fishes
and other turtles.
Of about 225 species, 65 of which live in North America, those of
certain aquatic kinds commonly sold in markets as choice food are
known as "terrapins". The few kinds which live almost wholly on land
are commonly called "tortoises" -- the largest of these being the giant
tortoises found on the Galapagos and certain other tropical islands;
turtles which reach a weight of 600 pounds and an age of 100 years or
In the middle West there are three land turtles: the Box Turtle, the
Ornate Box Turtle and the Wood Turtle. A fourth species, Blanding's
Turtle, is largely aquatic. The Ornate Box Turtle is found mainly in
prairies and open woods. The Wood Turtle lives in damp woods and
pastures but some hibernate over the winter in creek beds or shallow
water. The box turtles have dome-like shells, usually hibernate in soft
earth or vegetation, and their food -- about half plant and half animal -
- includes mushrooms, insects, worms, slugs, snails, dead animals and
strawberries. Their greatest enemy is fire.
A turtle has no housing problem.
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Update: June 2012