A bullwhip is a single-tailed whip, usually made of braided leather, designed as a tool for working with livestock. Bullwhips are pastoral tools, traditionally used to control livestock in open country. A bullwhip's length, flexibility, and tapered design allows it to be thrown in such a way that, toward the end of the throw, part of the whip exceeds the speed of sound—thereby creating a small sonic boom. Many modern "sport" whip crackers claim that the bullwhip was rarely, if ever, used to strike cattle, but this is a matter for debate.