Shell Structure

The carapace, the top shell, protects the turtle’s back. The shell of a box turtle is composed of many bony plates, or scouts, and has a dome shape. These joined scouts are made of keratin, the same stuff that people utilize in their fingernails. Predators and environmental dangers, such as falling objects or other creatures, are shielded from the carapace.

There is a clear structure to the arrangement of the carapace's scouts, and the surface of each cute displays concentric growth rings. You may determine the turtle's age by looking at its growth rings, which show phases of growth. The scouts do double duty as a covering and a thermoregulatory for the turtle. They do this by absorbing and reflecting sunlight.

The turtle's body is further protected by the marginal scouts, which run along the carapaces outside the border. Overlapping these scouts creates a tight seal that shields the shell's delicate margins from water loss.

The vertebral scouts trace the spine of the turtle from head to tail across the turtle's carapace. The scouts not only assist the turtle's weight disperse, but they also support the shell structurally.

Covering the sides of the turtle's shell are the costal scouts, which are situated between the marginal and vertebral scouts. The mobility and flexibility provided by these scutes enable the turtle to withdraw its limbs and head within its shell for safety.

Turtles hide their bellies with the plastron, the lowest portion of their shell. As an extra layer of defense, box turtles' plastrons are hinged so that they may shut snugly against the carapace. Finitely attached to the underlying bone are a number of bony plates that make up the plastron.

The bridge is a structure that joins the two halves of the shell, the plastron, and the carapace, at their junction. Because the bridge is bendable, the turtle may adjust its body size to suit its environment. Additionally, it protects the turtle's internal organs largely.