The employment of domestic animals for tillage or transport is known as animal traction. The tenn is generally understood to include pack transport as well as the "pulling" work of animals. In various parts of the world cattle, buffaloes, yaks, horses, donkeys, mules, camels, llamas, elephants, reindeer, goats and dogs are used for transport, crop cultivation, water-raising, milling, logging and land excavation or levelling.