Chase (live). Be chased (fall).

Over the past sixty million years nature has pressured the growth of animals all over the globe into two simple categories: chase(live) / be chased(fall). Off the top of ones head many can strike up thoughts of a few elite mammals that hold gold in the game of speed. 

Without going into specific detail, two ancient families have sat on the thrown of endurance for hundreds of millenia: Felines and Canines. Cats genetically are built for sprinting, sneaking up on prey and taking them suddenly and unaware. Dogs on the other hand are designed for explosive endurance, running down targets sometimes over 50+ miles. 

Humans developed along side both these kings of beasts not so much as to outrun them, but to outrun each other; all the while developing what is now called "fight or flight" response. The salient fact is that the fastest animals on earth include those that hunt and those that are hunted-- we are indeed in those categories; possessing more sweat glands then any organism on earth we are without doubt made to run, and run far. Theoretically there exists no other land mammal that can upstage a homo sapien in long distance running. Without fur, fangs, disproportionately accessible strength -- running is our biological million dollar scratch off in the genetic lottery. 

To paraphrase British biologist Richard Dawkins: "For when a wolf chases a herd of caribou it may be more important for an individual caribou to outrun the slowest member of the herd than to outrun the wolf."  As people, we ritually practice running and triumph; competing in activities from marathons to hurdling in order to be victorious over one-another and have our hand raised as the fastest--strongest--the most enduring of our species.