Cave men realized that trying to kill a single woolly mammoth was impossible. Instead they used to kill mammoths by panicking the herd in a series of attacks so that the herd got tighter and tighter as a group. The herd would run together in this tight pack following the mammoth directly in front of them until the group moved as if it were indeed a single beast. The attacks led the herd along a pre designated route that the cavemen had plotted until finally the lead mammoth plunged over a cliff. The herd, acting as one, and tightly packed, were unaware of what was happening in front of them until it was too late to stop.
Bull or bear. This methodology is still in use today - the question is - which herd is being led right now?