The First Horse

PHyracotherium ("Hyrax-like beast") is better known as Eohippus, which means "Dawn Horse" is an extinct genus of very small (about 60 cm in length) perissodactyl ungulates that lived in the woodlands of the Northern Hemisphere, with species ranging throughout Asia, Europe, and North America during the early Tertiary Period and the early to mid Eocene Epoch, about 55—45 million years ago with the earliest fossil specimen found at the Tsagan Khushu Quarry 1 site, Mongolia averaging about 60 cm in length and weighing around 15—16 kg (36 lbs)

This small, dog-sized animal was an ancestor of Equus caballus,the first "true" horse and was once considered to be the earliest known member of the Equidae before the type species was reclassified as a palaeothere, of a perissodactyl family related to both horses and brontotheres.