Ranching is the practice of raising grazing livestock such as cattle and sheep on large tracts of land, known as ranches. Ranches generally consist of large areas, but may be of nearly any size. If the ranch includes arable or irrigated land, the ranch may also engage in a limited amount of farming, raising crops for feeding the animals, such as hay and feed grains. Ranching is a subtype of farm, and people who own or operate a ranch are called ranchers, cattlemen, or stockgrowers. Ranching is also a method used to raise less common livestock such as horses, elk, American bison, ostrich, emu, and alpaca. Herding is the practice of caring for roaming groups of livestock over a large area, and ranchers and cowboys often herd animals toward favorable grazing areas. Ranching and the livestock industry is growing faster than any other agricultural sector in the world.