There was never a time during the pre-reservation history of the plains tribes that they could not remember hunting, eating, or living without the Buffalo.  Before tribes had horses, they organized massive drives in which entire herds were driven over cliffs.  It was effective but wasteful since most times many more were killed than could be processed and eaten in the short time before the meat spoiled.  After horses were acquired, the hunt became more selective and efficient.  However, the risk to the hunter was increased proportionately.  The ideal strategy was to have enough mounted hunters to ride hard and turn the herd into itself while killing the animals they wanted from the outside perimeter.  But Buffalo were fast, unpredictable, and dangerous.  The hunts were chaotic and the outcome, while assuring meat and skins for the future, usually carried injuries and sometimes fatalities.