Sonnentanz
Trosper is responsible for holding the Eastern Shoshone Sun Dance each August on the Wind River Indian Reservation. This duty was passed down to Trosper through genealogical lines for seven generations, and also includes receiving and caring for a medicine bundle used in the ceremony. Trosper received the leadership of the Sun Dance through the line of his great-grandfather John Trehero (sometimes spelled Truhujo), who led the ceremony for much of the 20th century and authorized a branch of the Sun Dance on the Crow Reservation in 1941 to be led by Tom Yellowtail (Crow).