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Posted by on Jul 3, 2015 in TellMeWhy |

How Does a Turtle Get into Its Shell?

How Does a Turtle Get into Its Shell?

A baby turtle is born with a shell that is just the right size for its body. As the turtle grows, the shell also grows. The top of a turtle’s shell is divided into sections. These are called shields. The turtle’s outer shell is made of a thin layer of keratin, like your fingernails.

But underneath that layer, there is a layer of bony plates that give the shell its shape. The ribs and vertebrae (backbones) are part of the shell too. Many young turtles show growth rings in each horny shield. Each ring stands for a year’s growth.

For example, a two-year-old turtle has two growth rings on each shield. After five or ten years, however, you can no longer figure out the turtle’s age by its rings. These rings have either become too crowded together, or have begun to wear off.

At this stage the shell looks like just one solid shield, but because it’s made up of multiple bones, it is formed through the fusion of the turtle’s ribs and vertebrae. It’s a body design that was built to last, representing millions of years of fine-tuning.

Content for this question contributed by Jason Williams, resident of, Milford, Pittsburgh, Allegheny County, Pennsylvania, USA