The horse (Equus ferus caballus) is a hoofed (ungulate) mammal, a subspecies of one of seven species of the family Equidae The horse has evolved over the past 50 million years from a small multi-toed creature into the modern large, single-toed animal Humans began to domesticate horses around 4000 years BC, and their domestication is believed to have been widespread by 3000 BC