Asinus is a subgenus of Equus (single-toed (hooved) grazing animal) that encompasses several subspecies of Equidae commonly known as asses, characterized by long ears, a lean, straight-backed build, lack of a true withers, a coarse mane and tail, and a reputation for considerable toughness and endurance.The common donkey is the best-known domesticated representative of the subgenus, with both domesticated and feral varieties.