Turtles are reptiles that have a shell and no teeth. The shell has as many as 60 bones. It has two sections: a carapace, covering the animal's back, and a plastron, covering its belly. In most species, large scales, called scutes, cover the bones. However, in softshell turtles, a tough, leathery skin replaces the scutes. Most Illinois turtles can pull their head and neck into the shell. In species such as box turtles and mud turtles, the plastron is hinged, allowing it to close on the carapace. Turtles usually have a tail. The tail of males is longer and heavier than the tail of females.