Anatomy of The Turtle's Shell

The turtle lives 'twixt plated decks
Which practically conceal its sex
I think it clever of the turtle
In such a fix to be so fertile.
-Ogden Nash

 turtle shell anatomy scutes  turtle shell anatomy scutes

Turtles are reptiles whose protection comes from a shell. The shell is composed of hard, bone plates covered by scutes. The scutes are made of keratin, the primary substance in hair, nails and hooves of other animals. The pigment melanin, present in the scutes, may form intricate designs and brightly colored patterns in some species.

The scutes of most turtles are arranged somewhat like the examples below.


Although the scutes form the familiar outer layer of the shell, it is the bony layer underneath which actually provides the shape, support and protective qualities of the turtle shell. The inner layer of bone is fused with the usual bony structures associated with all vertebrates, vthe vertebral column and ribs. The vertebrae are particularly interesting for the modifications that have occurred. The vertebrae of the neck and tail are small, allowing for a high degree of flexiblility, while the vertebrae of the central portion of the vertebral column are enormously elongated and inflexible, fused with the bony layer of the shell, acting as a support for the carapace.

There are many health implications associated with shell anatomy. For instance, if the outer keratin is breached by infection or injury, the turtle can lose its protection and infection can proceed into the bony layer and the body cavity, threatening the turtle's life. Another example is that the rigid shell prevents motion of the ribs. Because of this, turtles lack the diaphragm that allows other animals to cough. If fluid enters the lungs (which are located just under the carapace) pneumonia presents deadly dangers since the turtle will not be able to easily rid itself of the fluid, and infection is likely.

Although the shell provides excellent protection from many predators, it can also make the turtle vulnerable to health problems if it is not given good care in captivity.

 turtle shell anatomy scutes  turtle shell anatomy scutes

For more on turtle anatomy: Euro Turtle's anatomy page

 turtle shell anatomy scutes turtle shell anatomy scutes turtle shell anatomy scutes turtle shell anatomy scutes

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