The box turtle shell is a highly effective defense system.
The eastern box turtle (Terrapene carolina carolina) and its close relatives are known for their ability to close their shell remarkably well. This is possible because of the hinged plastron, the lower part of the shell. When threatened, the turtle can pull in its head, legs and tail. Then close the shell almost like a protective door. This defense can be especially useful against predators. Curious and strong animals, such as raccoons, may pose a serious threat, but a tightly closed shell makes the turtle much harder to reach.
