A crayfish exoskeleton is the tough external material, made from chitin and calcium carbonate, that surrounds, supports and protects a crayfish's body. The exoskeleton also protects the crayfish through times of drought, allowing the animal to locate another source of water.
There are internal structures on the exoskeleton called apodemes that serve as anchor points for muscles and are six times stronger than tendons. Apodemes stretch to store elastic energy for movement such as jumping, swimming and grasping things. The crayfish’s powerful claws are actually legs that have evolved into tools.
Crayfish shed their exoskeletons several times per year as the animal grows in a process called moulting. The new exoskeleton is soft and leaves the animal vulnerable to injury and predation for a short period of time while the exoskeleton hardens.
There are more than 300 species of crayfish, with the highest diversity found in the southeast U.S. In nature, crayfish are found in ponds, lakes, streams and rivers. The state of Louisiana raises crayfish on aquaculture farms, and 70 percent of the harvest is consumed by humans locally. They are also used for fish bait and sold as pets. Crayfish are also known as crawdads, mudbugs, and yabbies. Their name originates from the French word ecrevisse.