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Friday, Mar 29, 2024

Born To Run

Millions of years ago our common ancestor with chimpanzees made an extraordinary decision. It gradually took its knuckles off the ground and began to walk on two legs. Of course, this was not actually a conscious decision. Evolution selected for this occurrence because, for some arcane reason, it was more advantageous to be a biped than a quadruped. That’s one conclusion, but it’s not very satisfying so I’m going to pretend you’re interested and delve further. 


Our quasi-chimp ancestor abandoned invaluable traits that benefit chimps. Those seemingly innocuous animals are much stronger than humans. They are also masters of climbing, which is an excellent evasion skill. With strength and the ability to evade predators, chimps do okay for themselves in the competitive animal kingdom. Thus, a frail biped must have some uncanny ability because evolution doesn’t make mistakes. Nature wouldn’t select for our bipedal predecessor if it couldn’t survive in its environment.  


The transition from four to two feet brought about anatomical changes that may explain the bipedal advantage. Our early ancestor, known in science as Australopithecus afarensis, developed protruding butts, arched feet, and Achilles tendons. All these traits are lacking in chimps and superfluous in the process of walking. However, they are essential for running. Butt muscles give us power when we run, our foot structure allows for balance, support, and comfort, and Achilles let the foot flex freely throughout our gait. Furthermore, by standing upright, we began dissipating heat much more efficiently. We resided in a very hot climate several million years back and the sun’s rays struck the entire back of all our quadruped friends. But we, as bipeds, only felt the sun’s heat on our shoulders and heads. We were able to stay cooler much better and body temperature regulation is also crucial to running. This leads to the next clue: we can sweat and other animals cannot. Sweating is our homeostasis when our body temperature is getting too high, but all other animals have to inefficiently pant out the heat. It’s much easier to run if you can sweat than if you can’t.


In order to synthesize these random features into a meaningful claim, I’ll need to mention two other remarkable differences between Australopithecus afarensis (us) and chimps. Archeologists have found that as we stood erect our heads and jaws shrunk, our brains grew, and we began eating meat. Our new diet that included meat gave our brains nutrients for it to grow. Meat is also not as tough as the roots and herbs chimps eat so we no longer needed big heads and jaws to chew through those veggies. To eat meat we had to kill the meat, but archeological digs have determined that we did not create weapons for another million years. 


The answer is persistence hunting. We chased animals over vast distances until they passed out. Our butts, Achilles, stature, sweat glands, and feet all enabled us to run very efficiently. We are better at distance running than any other animal. Running was the bipedal secret that gave birth to what distinguished early-man from its chimpanzee counterparts. 


We evolved to run and use that skill as a predatory technique to help get meat, which made us more human than we could ever imagine. Our brains grew and our heads shrunk because of what we ate but we could only eat meat because we could kill prey by running them to death. Running is essential to our evolutionary history; it is part of our genetic code. There’s something undeniably natural and cathartic about going out for a few miles in the morning or a nice jog at sunset. Running is part of how we came to be and continued to thrive; it made us human. 


Artwork by TAMIR WILLIAMS


JOSH CLAXTON '18 is from Summit, N.J.


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