The 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. Crawfish 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. Crawfish 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 European crawfish is particularly prized for food despite its small size. Some cave-dwelling crawfish species are blind, such as those of Kentucky's Mammoth Cave.
Scientific classification: Crawfish belong to the families Astacidae (northern hemisphere), Austroastacidae (Australian region), and Parastacidae (southern hemisphere) of the order Decapoda. The European crawfish is classified as Astacus pallipes. The blind crawfish of Kentucky's Mammoth Cave is classified as Cambarus pellucidus.