Turtles of Wisconsin
Shells and Skin
Some aquatic turtles, like this painted turtle,
shed their scutes in mid-to-late summer. Look
closely and you can see scutes that look like
they're peeling off.
If you were asked what makes a turtle a turtle, you might answer, "its shell." The shell is certainly the part of a turtle that gets it noticed. The turtle shell is made up of about 60 different bones. The top of the shell is called the carapace, the bottom is the plastron, and the pieces that join top and bottom together are called bridges. The turtle's ribs and backbone are fused to the carapace.
Scutes (large scales) cover the shell and help keep bacteria and fungi from invading the underlying bone. Scutes are made up of keratin, similar to what makes up our fingernails. The scutes also contain all of the shell's patterns and colors. Wisconsin's two softshell species of turtles don't have scutes. They have a single leathery covering over their bone and cartilage shell. Hatchlings and young turtles are especially vulnerable to predators because their shells are not entirely hardened.
All turtles are covered with dry, scaly skin. In aquatic turtles, the scales help prevent excess water from entering the body. Turtles shed their skin, but it's not usually shed in large pieces. Some aquatic turtles also shed their scutes annually.
Where do you often see turtles? You probably spot them basking on floating logs or other debris. Basking is important for regulating a turtle's body temperature and it aids in digesting food. Vitamin D is needed for the turtle to absorb calcium from food. Why do you suppose that this is important? Calcium is important for shell development in younger turtles and it's needed for producing healthy eggshells in female turtles.
Next Page - Turtle Eggs >>
