Crayfish

Crayfish, also crawfish, common name for any crustacean resembling but smaller than their relatives the lobsters, ranging in length from 2 to 40 cm (0.8 to 16 in); the first of their five pairs of walking legs is equipped with strong claws. Crayfish live in freshwater rivers and streams in temperate climates; one family is confined to the northern hemisphere, another to the southern hemisphere, and a third to the Australian region.

Crayfish usually burrow into the banks of streams or ponds and feed upon live or decaying animal or vegetable matter. The male inserts sperm into a receptacle in the female's thorax in the fall; the eggs, laid in the spring, are then fertilized and hatch in eight weeks or less. The young remain with the mother for a short while; after several molts, they reach adult size. The animals can live for three years or longer. The white-clawed crayfish is particularly prized for food despite its small size. Some cave-dwelling crayfish species are blind, such as those of Kentucky's Mammoth Cave. Like other crustaceans, crayfish are capable of regenerating lost limbs during molting. See also Regeneration.

Scientific classification: Crayfish belong to the families Astacidae (northern hemisphere), Austroastacidae (Australian region), and Parastacidae (southern hemisphere) of the order Decapoda. The white-clawed crayfish is classified as Austropotamobius pallipes. The blind crayfish of Kentucky's Mammoth Cave is classified as Cambarus pellucidus.