Similar to the Mongols, Tibetans are nomadic herdspeople, herding sheep, yak, horses, goats and cattle in a very cold and windy environment. A great help for survival on the Tibetan plateau is the "yak", a very strong buffalo-like animal. It carries people and heavy loads, works the land, climbs like a goat or swims a river. Yak meat and milk are basic foods for the most Tibetans. Skins are used for boats, tents and boots. Manure is dried and used as fuel. The tail becomes a whip. The skull and horns are mounted above entrances to keep out evil spirits. Yak butter is an effective skin-protection against sun-burn and the extreme cold. The above shoe is called: "Doksun" and is made of a hand knitted sheep and yak woollen upper, decorated with pieces of felt, stitched and trimmed with colourful threads. The soles are cut from vellum or parchment and simply folded around the bottom of the shoe with a needle and heavy thread.