We remember those Old Westerns. Out on the lonesome prairie, the cowboys sipping coffee while the herd quietly mills around munching food, drinking creek water, until something catches their attention. A cougar yell, ominous storm clouds or the rattle of a snake; something sets them on edge. They stand as if frozen, heads up, eyes wide open, nervous and poised to run. Someone drops a pan or accidentally discharges a gun, any sudden noise and the stampede is on.