Did you know there are over 400 different breeds of horses. A horse called the  Hyracotherium was one of the first horses that lived. At first horses were wild, but around 3500 B.C. people started to tame horses.The walking speed of a horse is 4 - 5 miles per hour. A horse is also measured by a unit hand. A fully grown horse will eat 16 - 26 lb of food, and drink 10 - 12 gal of water! Horses will not sleep for more than 3 hours per day and will sleep throughout the day in 10 - 15 minute spells. These are some interesting facts about horses.