Bison do not give up their fibre easily! These animals are not tame. It may be collected in the Spring when the bison rub it off on bushes or posts. It must be sorted to separate the different types of fibre. It’s only the soft undercoat, or down that is desirable for yarn. Bison is hypo-allergenic. It is highly insulating, so very warm. It becomes softer and fluffier with washing. Bison is an exotic fibre similar to cashmere or qiviut.