How many Equus species are there?

Walker's Mammals of the World lists 7 living species of Equus. These include the domestic horse (and its wild cousin, Przewalski's horse), three species of asses, and three species of zebras. At the present time, truly wild horses exist only in Central Asia (Equus caballus przewalski). The other so-called "wild horses" are feral animals, the descendants of domestic animals that escaped from captivity. Wild asses occur in Asia and Africa, and the striped equines, the zebras and the recently extinct quaggas, are exclusively African. Though horses had been abundant for 50 million years in North America, they all became extinct there 10,000 years ago.

A Somali wild ass, now extremely rare. Asses typically live in desert environments. Note the stripes on the legs, suggesting that like other modern equines they are derived from zebrine ancestors.

The domestic donkey is descended from wild ass ancestors.