Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus.
The kiang has also larger and more horse-like hoofs, and the tail is haired higher up, thus approximating to Equus caballus przewalskii.
The controversy depends upon the consideration of a wealth of detail, which should be studied in Ridgeway's book; but zoological authorities are sceptical as to the suggested species, Equus caballus libycus.
