... Man survived the fierce test of the Ice Ages because he had the flexibility of mind to recognize inventions and turn them into community property. Evidently the Ice Ages worked a profound change in the way man could live. They forced him to depend less on plants and more on animals. The rigors of hunting on the edge of ice also changed the strategy of hunting. It became less attractive to stalk single animals, however large. The better alternative was to follow the herds and not to lose them- to learn to anticipate and in the end to adopt their habits, including their wandering migrations.
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