Animals have been used for transportation for a long, long time. Horses were ridden on horseback or pulled a cart or carriage. Donkeys were ridden or pulled carts. Mules were ridden or carried supplies. Ancient Arabs trained dromedary camels to carry the Arabs on the camels' backs. Ancient Indians trained elephants to carry people. They also trained water buffalos to pull carts. Ancient South Americans trained llamas and alpacas to pull people in carts. Ancient Arctic Eurasian Natives trained reindeer to pull them in sleighs. Native American Eskimos trained dogs to pull people in sleds. Oxen were trained to pull carts with people. Not any new animals have been trained to transport people (except for entertainment), and all these animals have kept their jobs for hundreds and thousands of years.