The Domestic Sheep (Ovis aries) is the most common species of the sheep genus. It is a woolly ruminant quadruped that probably descended from the wild moufflon. Many breeds of sheep exist, generally classified as wool class breeds and hair class breeds. Farmers develop wool breeds for superior wool quantity and quality (fineness of fibers), wool staple length and degree of crimp in the fiber. Hair class sheep are the original class of sheep, developed worldwide for meat and leather.