Ovis aries; Print; Domestic sheep (Ovis aries) are quadrupedal; ruminant mammals typically kept as livestock. Like most ruminants; sheep are members of the order Artiodactyla; the even-toed ungulates. Although the name sheep applies to many species in the genus Ovis; in everyday usage it almost always refers to Ovis aries. Numbering a little over one billion; domestic sheep are also the most numerous species of sheep. An adult female sheep is referred to as a ewe; an intact male as a ram or occasionally a tup; a castrated male as a wether; and a younger sheep as a lamb.; 1700-1880