By 2004, we’d found enough evidence to publish a paper in Nature where we declared, “Humans were born to run.” We cited the many dozens of adaptations in the human body that had made us into superlative endurance runners, even compared to dogs and horses.

Before bows and arrows and before horses were tamed, we did “persistence hunting” where we ran kudu, wildebeest and zebra into exhaustion. These animals can’t pant when they gallop. They overheat. People would find a big animal and chase it till it collapsed. You need no technology to do this, just the ability to run long distances, which all of us have.