Horses, asses and zebras live in open grasslands and scrubland, feeding mainly on grass. They are ungulates, a group of mammals that have hooves instead of claws on their feet. Horses are from the odd-toed group, having just a single toe. All horses have a mane of hair on their necks, which stands upright in all but domestic horses. Their long tails are covered with hair all over in the horses but only at the tip in asses and zebras. Baby horses, called foals, can walk soon after birth. Other members of the horse family are the kiang and onager.

Teeth

Horses have sharp front teeth for biting off blades of grass, and grinding back teeth for chewing. The jaw is deep and muscular to crush tough grasses. The teeth keep on growing so that they are not worn away by constant feeding.

Domestic horses

Humans began to domesticate horses around 4000 BC, probably in Kazakhstan and Ukraine. They were bred for different purposes, including getting about, working the land and for use in war. Horse breeds are divided into three main categories based on their temperament or physical build. The first category, "hot-bloods" were capable of running at speed over long distances; they were suitable for racing or, in the past, riding into battle. The second category, "cold-bloods", such as draft horses, were suitable for heavy work such as pulling ploughs or carriages. The final category, "warm-bloods", were crosses between hot bloods and cold bloods, often created specially for riding purposes, including dressage and show-jumping.

Ponies

 Ponies are really the same animals as horses, but have been bred to have different characteristics. They are usually smaller, with thicker manes, tails and coat hairs. They also have shorter legs, are of stockier appearance and have shorter heads. Ponies are often used for riding, but in some parts of the world they are still used as working animals or for pulling vehicles.

Donkeys

Donkeys, or asses, are small members of the horse family with an erect mane and long ears. Many donkeys are domesticated, especially in hilly regions. They are more suited to living in rough hill country than horses. If a horse and a donkey breed, their offspring is called a mule, and is sterile, meaning it cannot reproduce.