We Evolved Running Prowess To Chase Each Other, Not Just Animals

Several readers wrote in to make points I’d missed in my column on the way running shaped the human body. While it’s true that humans can excel at long distance running, there’s another area where members of our species far outcompete all other animals – throwing. Well, that applies to many humans, though sadly, not me. 

I enjoyed reading your "Born to Run" article in today's Inquirer.  As an athlete and student of comparative vertebrate anatomy it has been an interest of mine for quite a while.  I realize it wasn't really the subject of your piece, but I think it would have been worthwhile to point out that although humans are slightly better distance runners than the best of the rest of the animal kingdom, there is one physical skill that we are far better at than any other animal and it was certainly of equal or greater importance in our evolutionary history: throwing, for distance and accuracy.  Chimps can barely throw, and even with lots of practice and ample rewards can't hit the proverbial side of a barn.

You also stated that early man hunted with "sticks and clubs" before weapons were invented.  I don't know if you were reporting what your expert said, but it is very likely that they threw stones, which would be more effective weapons than sticks and clubs. 

This reader also noted that we have a unique way of using those throwing-adapted arms to help us run:

Speaking of running, years ago I figured out why we bend our arms when we run.In Physics class, we learned that the natural (i.e., unforced) period of a pendulum is a function of the length of the pendulum (but not its weight).  Longer pendulums have longer natural periods of oscillation than shorter pendulums.  When we walk, we hold our arms relatively straight such that they naturally swing at the same rate as we step, with our right arm swinging forward as our left foot steps forward (for balance) and then back as our right foot steps forward, and analogously for our left arm.

But, when we run, the timing of our strides is quicker than when we walk.  In order for the swinging of our arms to match our quicker running strides, we bend our arms to shorten the pendulum length and thereby decrease their natural period of oscillation. 

I also got an interesting note from evolutionary psychologist David Buss at the University of Texas. He suggested that there were three possible functions that would have contributed to the evolution of distance running:

“large game hunting, warfare [tribal raids often required 5 days travel to attack, and then fleeing back to home base], or simply fleeing groups of hostile humans.

Most seem to assume it was just to get food, but ability to long-distance run away from hostile humans likely meant living versus dying.”

That rings true. If the present is any indication of the past, the worst enemy of humans has always been other humans.