Bison Down
Bison Down is the soft undercoat of the American Bison. The coat of the bison contains two different types of fiber. The main coat is made up of coarse fibers (average 59 micrometers) called guard hairs, and the downy undercoat (average 18.5 micrometers). This undercoat is shed annually and consists of fine, soft fibers which are very warm and protect the animal from harsh winter conditions.
Read more about this topic: Animal Fiber, Wool