After all, what else did we have going for us? Nothing, except we ran like crazy and stuck together. Humans are among the most comunal and cooperative of all primates; our sole defense in a fang-filled world was our solidarity, and there's no reason to think we suddently disbanded our most crucial challenge, the hunt for food. I remembered what the Seri Indians told Scott Carrier after the sun had set on their persistence-hunting days. "It was better before," a Seri elder lamented. "We did everything as a family. The whole community was a family. We shared everything and cooperated, but now there is a lot of arguing and bickering, every man for himself."  Running didn't just make the Seris a people...it also made them better people.
Christopher McDougall, Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen
cooperation, running