"Typically, yak produce two different types of hair. The first is the outer "guard hair" which is the longer, coarser, and stronger hair. While guard hair grows over the entire animal, the longest and strongest guard hair is found on the animals tail and skirt. Because of its strength and coarse nature, the guard hairs are typically carded and then spun worsted. Using multiple plies the guard hairs are then braided into ropes, halters, and belts or weaved into very durable rugs and bags.
The second hair produced is the short, fine, soft undercoat or "down hair" which is produced by the animals during the winter and is an incredible insulator. Yak living in cold climates will produce from one to two pounds of down annually. The down is shed in the spring and is harvested by combing. The down, with a diameter of 14-16 microns, is very soft and is comparable to cashmere or camel in softness and quality. Once separated from the guard hairs the down is processed into clouds and rovings and spun into yarn for the exotic fiber market."
