Primitive men are ecological analogs of lions, wolves, and hyenas... they have adopted pack hunting in the pursuit of big game.... habitually slaughtering surplus prey, storing food, feeding solid food to their young, dividing labor, practicing cannibalism, and interacting aggressively with competing species.... this way of life persisted for millions of years or longer and was abandoned in most societies only during the last few thousand years.

On Human Nature (1978) - Ch.4 Emergence