The horse (Equus ferus caballus) is a hooved (ungulate) mammal, a subspecies of the family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today.
Depending on breed, management and environment, the domestic horse today has a life expectancy of 25 to 30 years.
The height of horses is measured at the highest point of the withers, where the neck meets the back. This point was chosen as it is a stable point of the anatomy, unlike the head or neck, which move up and down.