Yak is called a “boat of the plateau”, and is a kind of mammal living in the highest place of the world. Yaks mainly live in the area of Tibet Plateau with an elevation above 3,000 meters. They can adapt to the alpine ecological conditions, are mild, docile and kind, and have strong endurance and hardy spirit. For the Tibetan ethnic group living the nomadic life for generation, their daily life is inseparable from yaks, which can be used for farming and transport. Yaks also are capable of remembering the way, are surefooted on dangerous roads and wetlands, so they can serve as guides for tourists. Milk, beef and ox hair provide the necessary food and clothing material for Tibetans who tenaciously live at high altitude, and become the source of strength of the Tibetan ethnic group.