Arabian horse
In the desert, humans were the only source of food and water for the Arabian horse. Where there was no pasture, the Bedouin fed their horses dates, a fruit of the date palm tree, and camel's milk. Arabians needed to live on very little food, and survive a dry climate that was very hot in the day but very cold at night. Weak horses did not live, and the horses who survived the desert also had to survive being ridden for war. Therefore, the Arabian horse became very tough and able to live in a harsh world.