From Jim Hamm's book "Bows & Arrows of the Native Americans", page 73, Decorations, Snakeskins..."A snakeskin covering is a practical addition to a sinew-backed bow. The Indians added this feature to their bows occasionally, but it was not common. They probably didn't like messing with a rattlesnake. But they sometimes used it, as I have seen a few sinew-backed bows from the Northern Plains and the West Coast which employed them." Pat