Peter Shelton

Born to Run

Posted in Animal Dreams, At the Movies, Watch columns by pshelton on September 15, 2011

I don’t run the Imogene; I’ve never run the 18 miles up and over from Ouray to Telluride. I don’t run much at all anymore, unless it’s to sprint after a grandchild who is crawling toward the stairs.

But I do remember the feeling, from years past, when limbs and lungs were working just right, and the trail led away into Siren-call hills and it felt as if I could run forever.

That’s the subject of the bestseller Born to Run, by Christopher McDougall – that we as a species evolved to run and in fact became the big-brained creatures we are because we were runners. McDougall calls homo sapiens Running Man.

McDougall also addresses the Neanderthal riddle in Born to Run. That is the mystery of why our stronger, hairier, highly successful cousins vanished soon after the appearance in Europe of modern humans. (This goes back to a column I wrote several weeks ago about the search for a mutant gene or genes that separated us from the Neanderthals.)

McDougall is a runner himself and actually spends most of the book writing about the Tarahumara Indians of Mexico, who are great long-distance runners and the inspiration for the current craze of running barefoot. McDougall himself became a barefoot convert.

But it is his chapter on the growing understanding, over the last 20 years or so, of human morphology that really grabbed me. He and a trio of evolutionary scientists, two of them from Utah, believe that man survived, where Neanderthals didn’t, because of our running ability.

It started in the 1980s when U of U grad student David Carrier and his mentor Dr. Dennis Bramble divided the animal kingdom into “walkers” and “runners.” (Most experts on human evolution believed, and maybe still believe, that man abandoned the trees to walk upright.) Pigs and chimps are walkers; they run only in an emergency. Horses and dogs are runners. If humans were walkers, we should line up more closely with pigs and chimps. If we were truly runners, Bramble and Carrier believed, they would see key morphological similarities with running animals.

The first thing they had to get out of the way was our missing tail. Man is the only tailless running biped in the whole history of vertebrates. How do we balance on the run?

Turns out we have something called a nuchal ligament connecting the back of the skull to the top of the spine. It’s there to stabilize the head while moving fast. Chimps and pigs don’t have them; dogs and horses do.

We also have Achilles tendons connecting our heels and calf muscles. They store energy like a rubber band. They’re jumping springs. They’re not much help in walking, but running is essentially jumping from foot to foot.

And we have big butts. (Thank you, Pee-wee Herman.) Humans have big butts to keep our big heads and upper bodies from pitching forward while running. Look at chimps; they have no butts.

All three of these adaptations, Carrier and Bramble profess, were designed for running, not walking.

But the researchers’ really big discovery was about breathing: All running mammals take exactly one breath per galloping stride – horses, rabbits, cats. Their bodies work like bellows to draw in and expel air from their lungs. There is only one exception – man. Humans, with our upright, two-legged gait, can breathe as much, or as little, as we need to. We may not be as fast as the four-legged bellows-breathing runners, but we can run, essentially, forever.

We also sweat. Cooling our machine is not tied to the lungs, as it is for pelt-covered creatures. Try running with your dog on a hot day, McDougall suggests. Your dog will need to stop and cool down before you do. “We can dump heat on the run, but animals can’t pant while they gallop.”

So, how did this weak, hairless, skinny creature survive? Enter Harvard evolutionary anthropologist Dan Lieberman, who took Bramble and Carrier’s findings and figured out how the endurance-running thing would be an evolutionary benefit. Lieberman knew we needed a lot of protein to feed our growing brains. But we didn’t have spear points two million years ago, and we didn’t have the thick bone and muscle that allowed Neanderthals to kill mastodons and rhinos. Could we have run a deer to death?

He thinks we could and did. And he used the example of the Kalahari Bushmen of southern Africa, who do it to this day. Eventually, as a frightened animal sprints away, again and again from a marathon pursuer, it will reach hyperthermia and collapse. (Check out the wonderful 2000 documentary, The Great Dance.)

As for the Neanderthals, McDougall says, they “ruled the world until the weather started getting nice.” A warmer climate at the end of the last glacial maximum was great for Running Man. Grasslands and antelope proliferated. Big muscled Neanderthals couldn’t run as humans did. Their prey, the bison and mastodons, retreated deeper into the dwindling forests, and the Neanderthals followed.

Now we’ve forgotten how to run, McDougall writes. We’ve gotten soft. “We’ve taken our sinewy, durable, hunter-gatherer bodies and plunked them into an artificial world of leisure.”

All of us except the Imogene runners, that is.

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