Excerpt from the Thaw Catalog: On festive occasions among the Western Sioux, young men used to wear hair ornaments of this type, suspended from the back of their heads. This example consists of a rectangular strip of tanned skin, covered with vertical lanes of quillwork and edged with white seed beads. Usually it was surmounted by a few erect and trimmed feathers, and a horse tail streamer was attached to the lower end. The Sioux called this hair ornament a "buffalo bull's tail," a term which suggests this ornament used to be a decorated tail of that animal.
Physical dimensions: 
length 29 in ; width 2.375 in