wildebeest on a hot day and allow us to trot after it, and we can run it into the ground. We perspire to keep cool, but quadrupedal mammals lose heat by respiration—by panting. If they can’t stop to collect themselves, they overheat and become helpless. Most large animals can’t run for more than about nine miles before they drop. That our ancestors could also organize themselves into hunting parties, to harry quarry from different
