Chapter 28
TWENTY YEARS EARLIER, in a tiny basement lab, a young scientist stared into a corpse and saw his destiny staring back.
At that moment, David Carrier was an undergraduate at the University of Utah. He was puzzling over a rabbit carcass, trying to figure out what the deal was with those bony things right over the butt. The bony things bugged him, because they weren’t supposed to be there. David was the star student in Professor Dennis Bramble’s evolutionary biology class, and he knew exactly what he was supposed to see whenever he cut into a mammal’s abdomen. Those big belly muscles on the diaphragm? They need to anchor down on something strong, so they connect to the lumbar vertebra, just the way you’d lash a sail down to a boom. That’s how it is for every mammal from a whale to a wombat—but not, apparently, for this rabbit; instead of grabbing hold of something sturdy, its belly muscles were connected to these flimsy chicken-wing-looking things.
David pushed one with his finger. Cool; it compressed like a Slinky, then sprang back out. But why, in all mammaldom, would a jackrabbit need a spring-loaded belly?
“That made me start thinking about what they do when they run, the way they arch their backs with every galloping stride,” Carrier later told me. “When they push off with their hind legs, they extend the back, and as soon as they land on the front legs, the back bends dorsally.” Lots of mammals jackknife their bodies the same way, he mused. Even whales and dolphins move their tails up and down, while a shark slashes from side to side. “Think of an inchworming cheetah movement,” David says. “Classic example.”
Good; this was good. David was getting somewhere. Big cats and little rabbits run the same way, but one has Slinkies stuck to its diaphragm and one doesn’t. One is fast, but the other has to be faster, at least for a little while. And why? Simple economics: if mountain lions ran down all the rabbits, you’d have no more rabbits and, eventually, no more mountain lions. But jackrabbits are born with a big problem: unlike other running animals, they don’t have reserve artillery. They don’t have antlers or horns or hard-kicking hooves, and they don’t travel in the protection of herds. For rabbits, it’s all or nothing; either they dart their way to safety, or they’re cat food.
Okay, David thought, maybe the Slinkies have something to do with speed. So what makes you fast? David began ticking off components. Let’s see. You need an aerodynamic body. Awesome reflexes. Power-loaded haunches. High-volume capillaries. Fast-twitch muscle fiber. Small, nimble feet. Rubbery tendons that return elastic energy. Skinny muscles near the paws, beefy muscles near the joints …
Damn. It didn’t take David long to figure out he was heading toward a dead end. A lot of factors contribute to speed, and jackrabbits share most of them with their hunters. Instead of finding out how they were different, he was finding out how they were alike. So he tried a trick Dr. Bramble had taught him: when you can’t answer the question, flip it over. Forget what makes something go fast— what makes it slow down? After all, it didn’t just matter how fast a rabbit could go, but how fast it could keep going until it found a hole to dive down.
Now that one was easy: other than a lasso around the leg, the quickest way to bring a fast-moving mammal to a halt is by cutting off its wind. No more air equals no more speed; try sprinting while holding your breath sometime and see how far you get. Your muscles needs oxygen to burn calories and convert them into energy, so the better you are at exchanging gases—sucking in oxygen, blowing out carbon dioxide—the longer you can sustain your top speed. That’s why Tour de France cyclists keep getting caught with other people’s blood in their veins; those illicit transfusions pack in extra red-blood cells, which carry lots of extra oxygen to their muscles.
Wait a second … that meant that for a jackrabbit to stay one hop ahead of those snapping jaws, it would need a little more air than the big mammal on its tail. David had a vision of a Victorian flying machine, one of those wacky but plausible contraptions rigged with pistons and steam valves and endless mazes of wheezing levers. Levers! Those Slinkies were beginning to make sense. They had to be levers that turbocharged the rabbit’s lungs, pumping them in and out like a fireplace bellows.
David ran the numbers to see if his theory held up and … bingo! There it was, as elegant and niftily balanced as an Aesop’s fable: Jackrabbits can hit forty-five miles per hour, but due to the extra energy needed to operate the levers (among other things), they can only sustain it for a half mile. Cougars, coyotes, and foxes, on the other hand, can go a lot farther but top out at forty miles per. The Slinkies balance the game, giving the otherwise defenseless jackrabbits exactly forty-five seconds to either live or die. Seek shelter quickly and live long, young Thumper; or get cocky about your speed and be dead in less than a minute.
“You know,” he thought, “if you take away the levers, isn’t it the same engineering for every other mammal?” Maybe that’s why their diaphragms hooked on to the lumbar vertebra—not because the vertebra was sturdy and wouldn’t move, but because it was stretchy and would. Because it flexed!
“It seemed obvious that when the animal pushed off and extended its back, it wasn’t just for propulsion—it was also for respiration,” David says. He imagined an antelope racing for its life across a dusty savannah, and behind it, a streaking blur. He focused on the blur, froze it in place, then clicked it forward a frame at a time:
Click—as the cheetah stretches long for a stride, its rib cage is pulled back, sucking air into the lungs and …
Click—now the front legs whip back until front and rear paws are touching. The cheetah’s spine bends, squeezing the chest cavity and squishing the lungs empty of air and …
And there you had it—another Victorian breathing contraption, albeit with a little less turbo power.
David’s heart was racing. Air! Our bodies were all about getting air! Flip the equation, as Dr. Bramble had taught him, and you have this: getting air may have determined the way we got our bodies.
God, it was so simple—and so mind-blowing. Because if David was right, he’d just solved the greatest mystery in human evolution. No one had ever figured out why early humans had separated themselves from all creation by taking their knuckles off the ground and standing up. It was to breathe! To open their throats, swell out their chests, and suck in air better than any other creature on the planet.
But that was just the beginning. Because the better you are at breathing, David quickly realized, the better you are at—
“Running? You’re saying humans evolved to go running?”
Dr. Dennis Bramble listened with interest as David Carrier explained his theory. Then he casually took aim and blew it to smithereens. He tried to be gentle; David was a brilliant student with a truly original mind, but this time, Bramble suspected, he’d fallen victim to the most common mistake in science: the Handy Hammer Syndrome, in which the hammer in your hand makes everything look like a nail.
Dr. Bramble knew a little about David’s life outside the classroom, and was aware that on sunny spring afternoons, David loved to bolt from the labs and go trail-running in the Wasatch Mountains, which lap right up to the back of the University of Utah campus. Dr. Bramble was a runner himself, so he understood the attraction, but you had to be careful with stuff like that; a biologist’s biggest occupational hazard, second only to falling in love with your research assistants, was falling in love with your hobbies. You become your own test subject; you start seeing the world as a reflection of your own life, and your own life as a reference point for just about every phenomenon in the world.
“David,” Dr. Bramble began. “Species evolve according to what they’re good at, not what they’re bad at. And as runners, humans aren’t just bad—we’re awful.” You didn’t even need to get into the biology; you could just look at cars and motorcycles. Four wheels are faster than two, because as soon as you go upright, you lose thrust, stability, and aerodynamics. Now transfer that design to animals. A tiger is ten feet long and shaped like a cruise missile. It’s the drag racer of the jungle, while humans have to putter along with their skinny legs, tiny strides, and piss-poor wind resistance.
“Yeah, I get it,” David said. Once we came up off our knuckles, everything went to hell. We lost raw speed and upper-body power—
Good kid, Bramble thought. Learns quick.
But David wasn’t done. So why, David continued, would we give up strength and speed at the same time? That left us unable to run, unable to fight, unable to climb and hide in the tree canopy. We’d have been wiped out—unless we got something pretty amazing in exchange. Right?
That, Dr. Bramble had to admit, was a damn clever way to put the question. Cheetahs are fast but frail; they have to hunt by day to avoid nocturnal killers like lions and panthers, and they abandon their kills and run for cover when scrappy little thugs like hyenas show up. A gorilla, on the other hand, is strong enough to lift a four-thousand-pound SUV, but with a gorilla’s land speed of twenty miles per hour, that same SUV could run it over in first gear. And then we have humans, who are part cheetah, part gorilla—we’re slow and wimpy.
“So why would we evolve into a weaker creature, instead of a stronger one?” David persisted. “This was long before we could make weapons, so what was the genetic advantage?”
Dr. Bramble played the scenario out in his head. He imagined a tribe of primitive hominids, all squat, quick, and powerful, keeping their heads low for safety as they scrambled nimbly through the trees. One day, out pops a slow, skinny, sunken-chested son who’s barely bigger than a woman and keeps making a tiger target out of himself by walking around in the open. He’s too frail to fight, too slow to run away, too weak to attract a mate who’ll bear him children. By all logic, he’s marked for extinction—yet somehow, this dweeb becomes the father of all mankind, while his stronger, swifter brothers disappear into oblivion.
That hypothetical account was actually a pretty accurate description of the Neanderthal Riddle. Most people think Neanderthals were our ancestors, but they were actually a parallel species (or subspecies, some say) that competed with Homo sapiens for survival. “Competed,” actually, is being kind; the Neanderthals had us beat any way you keep score. They were stronger, tougher, and probably smarter: they had burlier muscles, harder-to-break bones, better natural insulation against the cold, and, the fossil record suggests, a bigger brain. Neanderthals were fantastically gifted hunters and skilled weapon-makers, and may very well have acquired language before we did. They had a huge head start in the race for world domination; by the time the first Homo sapiens appeared in Europe, Neanderthals had already been cozily established there for nearly two hundred thousand years. If you had to choose between Neanderthals and Early Us in a Last Man Standing contest, you’d go Neanderthal all the way.
So—where are they?
Within ten thousand years of the arrival of Homo sapiens in Europe, the Neanderthals vanished. How it happened, no one knows. The only explanation is that some mysterious X Factor gave us—the weaker, dumber, skinnier creatures—a life-or-death edge over the Ice Age All-Stars. It wasn’t strength. It wasn’t weapons. It wasn’t intelligence.
Could it have been running ability? Dr. Bramble wondered. Is David really onto something?
There was only one way to find out: go to the bones.
“At first I was very skeptical of David, for the same reason most morphologists would be,” Dr. Bramble later told me. Morphology is basically the science of reverse engineering; it looks at how a body is assembled and tries to figure out how it’s supposed to function. Morphologists know what to look for in a fast-moving machine, and in no way did the human body match the specs. All you had to do was look at our butts to figure that out. “In the whole history of vertebrates on Earth—the whole history—humans are the only running biped that’s tailless,” Bramble would later say. Running is just a controlled fall, so how do you steer and keep from smacking down on your face without a weighted rudder, like a kangaroo’s tail?
“That’s what led me, like others, to dismiss the idea that humans evolved as running animals,” Bramble said. “And I would have bought into the story and remained a skeptic, if I hadn’t also been trained in paleontology.”
Dr. Bramble’s secondary expertise in fossils allowed him to compare how the human blueprint had been modified over the millennia and check it against other designs. Right off the bat, he began finding things that didn’t fit. “Instead of looking at the conventional list, like most morphologists, and ticking off the things I expected to see, I began focusing on the abnormalities,” Bramble said. “In other words, what’s there that shouldn’t be there?” He began by splitting the animal kingdom into two categories: runners and walkers. Runners include horses and dogs; walkers are pigs and chimps. If humans were designed to walk most of the time and run only in emergencies, our mechanical parts should match up pretty closely to those of other walkers.
Common chimps were the perfect place to start. Not only are they a classic example of the walking animal, but they’re also our closest living relative; after more than six million years of separate evolution, we still share 95 percent of our DNA sequence with chimps. But what we don’t share, Bramble noted, is an Achilles tendon, which connects the calf to the heel: we’ve got one, chimps don’t. We have very different feet: ours are arched, chimps’ are flat. Our toes are short and straight, which helps running, while chimps’ are long and splayed, much better for walking. And check out our butts: we’ve got a hefty gluteus maximus, chimps have virtually none. Dr. Bramble then focused on a little-known tendon behind the head known as the nuchal ligament. Chimps don’t have a nuchal ligament. Neither do pigs. Know who does? Dogs. Horses. And humans.
Now this was perplexing. The nuchal ligament is useful only for stabilizing the head when an animal is moving fast; if you’re a walker, you don’t need one. Big butts are only necessary for running. (See for yourself: clutch your butt and walk around the room sometime. It’ll stay soft and fleshy, and only tighten up when you start to run. Your butt’s job is to prevent the momentum of your upper body from flipping you onto your face.) Likewise, the Achilles tendon serves no purpose at all in walking, which is why chimps don’t have one. Neither did Australopithecus, our semi-simian four-million-year-old ancestor; evidence of an Achilles tendon only began to appear two million years later, in Homo erectus.
Dr. Bramble then took a closer look at the skulls and got a jolt. Holy moly! he thought. There’s something going on here. The back of the Australopithecus skull was smooth, but when he checked Homo erectus, he found a shallow groove for a nuchal ligament. A mystifying but unmistakable time line was taking shape: as the human body changed over time, it adopted key features of a running animal.
Weird, Bramble thought. How come we acquired all this specialized running stuff, and other walkers didn’t? For a walking animal, the Achilles would just be a liability. Moving on two legs is like walking on stilts; you plant your foot, pivot your body weight over the leg, and repeat. The last thing you’d want would be stretchy, wobbly tendons right at your base of support. All an Achilles tendon does is stretch like a rubber band—
A rubber band! Dr. Bramble felt twin surges of pride and embarrassment. Rubber bands … There he’d been, thumping his chest about not being like all those other morphologists who “tick off the things they expect to see,” when all along, he’d been just as misguided by myopia; he hadn’t even thought about the rubber-band factor. When David started talking about running, Dr. Bramble assumed he meant speed. But there are two kinds of great runners: sprinters and marathoners. Maybe human running was about going far, not fast. That would explain why our feet and legs are so dense with springy tendons—because springy tendons store and return energy, just like the rubber-band propellers on balsa-wood airplanes. The more you twist the rubber band, the farther the plane flies; likewise, the more you can stretch the tendons, the more free energy you get when that leg extends and swings back.
And if I were going to design a long-distance running machine, Dr. Bramble thought, that’s exactly what I’d load it with—lots of rubber bands to maximize endurance. Running is really just jumping, springing from one foot to another. Tendons are irrelevant to walking, but great for energy-efficient jumping. So forget speed; maybe we were born to be the world’s greatest marathoners.
“And you’ve got to ask yourself why only one species in the world has the urge to gather by the tens of thousands to run twenty-six miles in the heat for fun,” Dr. Bramble mused. “Recreation has its reasons.”
Together, Dr. Bramble and David Carrier began putting their World’s Greatest Marathoner model to the test. Soon, evidence was turning up all over, even in places they weren’t looking. One of their first big discoveries came by accident when David took a horse for a jog. “We wanted to videotape a horse to see how its gait coordinated with its breathing,” Dr. Bramble says. “We needed someone to keep the gear from getting tangled, so David ran alongside it.” When they played back the tape, something seemed strange, although Bramble couldn’t figure out what it was. He had to rewind a few times before it hit him: even though David and the horse were moving at the same speed, David’s legs were moving more slowly.
“It was astonishing,” Dr. Bramble explains. “Even though the horse has long legs and four of them, David had a longer stride.” David was in great shape for a scientist, but as a medium-height, medium-weight, middle-of-the-pack runner, he was perfectly average. That left only one explanation: as bizarre as it may seem, the average human has a longer stride than a horse. The horse looks like it’s taking giant lunges forward, but its hooves swing back before touching the ground. The result: even though biomechanically smooth human runners have short strides, they still cover more distance per step than a horse, making them more efficient. With equal amounts of gas in the tank, in other words, a human can theoretically run farther than a horse.
But why settle for theory when you can put it to the test? Every October, a few dozen runners and riders face off in the 50- mile Man Against Horse Race in Prescott, Arizona. In 1999, a local runner named Paul Bonnet passed the lead horses on the steep climb up Mingus Mountain and never saw them again till after he’d crossed the finish line. The following year, Dennis Poolheco began a remarkable streak: he beat every man, woman, and steed for the next six years, until Paul Bonnet wrested the title back in 2006. It would take eight years before a horse finally caught up with those two and won again.
Discoveries like these, however, were just happy little extras for the two Utah scientists as they tunneled closer to their big breakthrough. As David had suspected on the day he peered into a rabbit’s carcass and saw the history of life staring back at him, evolution seemed to be all about air; the more highly evolved the species, the better its carburetor. Take reptiles: David put lizards on a treadmill, and found they can’t even run and breathe at the same time. The best they can manage is a quick scramble before stopping to pant.
Dr. Bramble, meanwhile, was working a little higher up the evolutionary ladder with big cats. He discovered that when many quadrupeds run, their internal organs slosh back and forth like water in a bathtub. Every time a cheetah’s front feet hit the ground, its guts slam forward into the lungs, forcing out air. When it reaches out for the next stride, its innards slide rearward, sucking air back in. Adding that extra punch to their lung power, though, comes at a cost: it limits cheetahs to just one breath per stride.
Actually, Dr. Bramble was surprised to find that all running mammals are restricted to the same cycle of take-a-step, take-a-breath. In the entire world, he and David could only find one exception:
You.
“When quadrupeds run, they get stuck in a one-breath-per-locomotion cycle,” Dr. Bramble said. “But the human runners we tested never went one to one. They could pick from a number of different ratios, and generally preferred two to one.” The reason we’re free to pant to our heart’s content is the same reason you need a shower on a summer day: we’re the only mammals that shed most of our heat by sweating. All the pelt-covered creatures in the world cool off primarily by breathing, which locks their entire heat-regulating system to their lungs. But humans, with our millions of sweat glands, are the best air-cooled engine that evolution has ever put on the market.
“That’s the benefit of being a naked, sweating animal,” David Carrier explains. “As long as we keep sweating, we can keep going.” A team of Harvard scientists had once verified exactly that point by sticking a rectal thermometer in a cheetah and getting it to run on a treadmill. Once its temperature hit 105 degrees, the cheetah shut down and refused to run. That’s the natural response for all running mammals; when they build up more heat in their bodies than they can puff out their mouths, they have to stop or die.
Fantastic! Springy legs, twiggy torsos, sweat glands, hairless skin, vertical bodies that retain less sun heat—no wonder we’re the world’s greatest marathoners. But so what? Natural selection is all about two things—eating and not getting eaten—and being able to run twenty miles ain’t worth a damn if the deer disappears in the first twenty seconds and a tiger can catch you in ten. What good is endurance on a battlefield built on speed?
That’s the question Dr. Bramble was mulling in the early ’90s when he was on sabbatical and met Dr. Dan Lieberman during a visit to Harvard. At the time, Lieberman was working on the other end of the animal Olympics; he had a pig on a treadmill and was trying to figure out why it was such a lousy runner.
“Take a look at its head,” Bramble pointed out. “It wobbles all over the place. Pigs don’t have a nuchal ligament.”
Lieberman’s ears perked up. As an evolutionary anthropologist, he knew that nothing on our bodies has changed as much as the shape of our skulls, or says more about who we are. Even your breakfast burrito plays a role; Lieberman’s investigations had revealed that as our diet shifted over the centuries from chewy stuff like raw roots and wild game and gave way to mushy cooked staples like spaghetti and ground beef, our faces began to shrink. Ben Franklin’s face was chunkier than yours; Caesar’s was bigger than his.
The Harvard and Utah scientists got along right from the start, mostly because of Lieberman’s eyes: they didn’t roll when Bramble briefed him on the Running Man theory. “No one in the scientific community was willing to take it seriously,” Bramble said. “For every one paper on running, there were four thousand on walking. Whenever I’d bring it up at conferences, everyone would always say, ‘Yeah, but we’re slow.’ They were focused on speed and couldn’t understand how endurance could be an advantage.”
Well, to be fair, Bramble hadn’t really figured that one out yet, either. As biologists, he and David Carrier could decipher how the machine was designed, but they needed an anthropologist to determine what that design could actually do. “I knew a lot about evolution and a little about locomotion,” Lieberman says. “Dennis knew a shitload about locomotion, but not so much about evolution.”
As they traded stories and ideas, Bramble could tell that Lieberman was his kind of lab partner. Lieberman was a scientist who believed that being hands-on meant being prepared to soak them in blood. For years, Lieberman had organized a Cro-Magnon barbecue on a Harvard Yard lawn as part of his human evolution class. To demonstrate the dexterity necessary to operate primitive tools, he’d get his students to butcher a goat with sharpened stones, then cook it in a pit. As soon as the aroma of roasting goat spread and the post-butchering libations began flowing, homework turned into a house party. “It eventually evolved into a kind of bacchanalian feast,” Lieberman told the Harvard University Gazette.
But there was an even more important reason that Lieberman was the perfect guy to tackle the Running Man mystery: the solution seemed to be linked to his specialty, the head. Everyone knew that at some point in history, early humans got access to a big supply of protein, which allowed their brains to expand like a thirsty sponge in a bucket of water. Our brains kept growing until they were seven times larger than the brains of any comparable mammal. They also sucked up an ungodly number of calories; even though our brains account for only 2 percent of our body weight, they demand 20 percent of our energy, compared with just 9 percent for chimps.
Dr. Lieberman threw himself into Running Man research with his usual creative zeal. Soon, students dropping by Lieberman’s office on the top floor of Harvard’s Peabody Museum were startled to find a sweat-drenched one-armed man with an empty cream-cheese cup strapped to his head running on a treadmill. “We humans are weird,” Lieberman said as he punched buttons on the control panel. “No other creature has been found with a neck like ours.” He paused to shout a question to the man on the treadmill. “How much faster can you go, Willie?”
“Faster than this thing!” Willie called back, his steel left hand clanging against the treadmill rail. Willie Stewart lost his arm when he was eighteen after a steel cable he was carrying on a construction job got caught in a whirling turbine, but he recovered to become a champion triathlete and rugby player. In addition to the cream-cheese cup, which was being used to secure a gyroscope, Willie also had electrodes taped to his chest and legs. Dr. Lieberman had recruited him to test his theory that the human head, with its unique position directly on top of the neck, acts like the roof weights used to prevent skyscrapers from pitching in the wind. Our heads didn’t just expand because we got better at running, Lieberman believed; we got better at running because our heads were expanding, thereby providing more ballast.
“Your head works with your arms to keep you from twisting and swaying in midstride,” Dr. Lieberman said. The arms, meanwhile, also work as a counterbalance to keep the head aligned. “That’s how bipeds solved the problem of how to stabilize a head with a movable neck. It’s yet another feature of human evolution that only makes sense in terms of running.”
But the big mystery continued to be food. Judging by the Godzilla-like growth of our heads, Lieberman could pinpoint the exact moment when the caveman menu changed: it had to be two million years ago, when apelike Australopithecus—with his tiny brain, giant jaw, and billy-goat diet of tough, fibrous plants—evolved into Homo erectus, our slim, long-legged ancestor with the big head and small, tearing teeth perfectly suited for raw flesh and soft fruits. Only one thing could have sparked such a dramatic makeover: a diet no primate had ever eaten before, featuring a reliable supply of meat, with its high concentrations of calories, fat, and protein.
“So where the f*ck did they get it?” Lieberman asks, with all the gusto of a man who’s not squeamish about hacking into goats with a rock. “The bow and arrow is twenty thousand years old. The spearhead is two hundred thousand years old. But Homo erectus is around two million years old. That means that for most of our existence—-for nearly two million years!—hominids were getting meat with their bare hands.”
Lieberman began playing the possibilities out in his mind. “Maybe we pirated carcasses killed by other predators?” he asked himself. “Scooting in and grabbing them while the lion was sleeping?”
No; that would give us an appetite for meat but not dependable access. You’d have to get to a kill site before the vultures, who can strip an antelope in minutes and “chew bones like crackers,” as Lieberman likes to say. Even then, you might only tear off a few mouthfuls before the lion opened a baleful eye or a pack of hyenas drove you away.
“Okay, maybe we didn’t have spears. But we could have jumped on a boar and throttled it. Or clubbed it to death.”
Are you kidding? With all that thrashing and goring, you’d get your feet crushed, your testicles torn, your ribs broken. You’d win, but you’d pay for it; break an ankle in the prehistoric wilderness while hunting for dinner, and you might become dinner yourself.
There’s no telling how long Lieberman would have remained stumped if his dog hadn’t finally given him the answer. One summer afternoon, Lieberman took Vashti, his mutty half border collie, for a five-mile jog around Fresh Pond. It was hot, and after a few miles, Vashti plopped down under a tree and refused to move. Lieberman got impatient; yeah, it was a little warm, but not that bad….
As he waited for his panting dog to cool off, Lieberman’s mind flashed back to his time doing fossil research in Africa. He recalled the shimmering waves across the sun-scorched savannah, the way the dry clay soaked up the heat and beamed it right back up through the soles of his boots. Ethnographers’ reports he’d read years ago began flooding his mind; they told of African hunters who used to chase antelope across the savannahs, and Tarahumara Indians who would race after a deer “until its hooves fell off.” Lieberman had always shrugged them off as tall tales, fables of a golden age of heroes who’d never really existed. But now, he started to wonder….
So how long would it take to actually run an animal to death? he asked himself. Luckily, the Harvard bio labs have the best locomotive research in the world (as their willingness to insert a thermometer in a cheetah’s butt should make clear), so all the data Lieberman needed was right at his fingertips. When he got back to his office, he began punching in numbers. Let’s see, he began. A jogger in decent shape averages about three to four meters a second. A deer trots at almost the identical pace. But here’s the kicker: when a deer wants to accelerate to four meters a second, it has to break into a heavy-breathing gallop, while a human can go just as fast and still be in his jogging zone. A deer is way faster at a sprint, but we’re faster at a jog; so when Bambi is already edging into oxygen debt, we’re barely breathing hard.
Lieberman kept looking, and found an even more telling comparison: the top galloping speed for most horses is 7.7 meters a second. They can hold that pace for about ten minutes, then have to slow to 5.8 meters a second. But an elite marathoner can jog for hours at 6 meters a second. The horse will erupt away from the starting line, as Dennis Poolheco had discovered in the Man Against Horse Race, but with enough patience and distance, you can slowly close the gap.
You don’t even have to go fast, Lieberman realized. All you have to do is keep the animal in sight, and within ten minutes, you’re reeling him in.
Lieberman began calculating temperatures, speed, and body weight. Soon, there it was before him: the solution to the Running Man mystery. To run an antelope to death, Lieberman determined, all you have to do is scare it into a gallop on a hot day. “If you keep just close enough for it to see you, it will keep sprinting away. After about ten or fifteen kilometers’ worth of running, it will go into hyperthermia and collapse.” Translation: if you can run six miles on a summer day then you, my friend, are a lethal weapon in the animal kingdom. We can dump heat on the run, but animals can’t pant while they gallop.
“We can run in conditions that no other animal can run in,” Lieberman realized. “And it’s not even hard. If a middle-aged professor can outrun a dog on a hot day, imagine what a pack of motivated hunter-gatherers could do to an overheated antelope.”
It’s easy to picture the scorn on the faces of those Masters of the Universe, the Neanderthals, as they watched these new Running Men puffing along behind bouncy little Bambis, or jogging all day under a hot sun to return with nothing but an armload of yams. The Running Men could get a load of meat by running, but they couldn’t run with a belly load of meat, so most of the time they carbo-loaded on roots and fruits, saving the antelope chops for special, calorie-boosting occasions. Everyone scavenged together—Running Men, Running Women, Running Kids, and Grampies—but despite all that team activity, they were more likely to dine on grubs than wild game.
Bleh. Neanderthals wouldn’t touch bugs and dirt food; they ate meat and only meat, and not gristly little antelopes, either. Neanderthals went Grade A all the way: bears, bison, and elk marbled with juicy fat, rhinos with livers rich in iron, mammoths with luscious, oily brains and bones dripping with lip-smacking marrow. Try chasing monsters like those, though, and they’ll be chasing you. Instead, you’ve got to outsmart and outfight them. The Neanderthals would lure them into ambushes and launch a pincer attack, storming from all sides with eight-foot wooden lances. Hunting like that isn’t for the meek; Neanderthals were known to suffer the kind of injuries you find on the rodeo circuit, neck and head trauma from getting thrown by bucking beasts, but they could count on their band of brothers to care for their wounds and bury their bodies. Unlike our true ancestors, those scampering Running Men, the Neanderthals were the mighty hunters we like to imagine we once were; they stood shoulder to shoulder in battle, a united front of brains and bravery, clever warriors armored with muscle but still refined enough to slow-cook their meat to tenderness in earth ovens and keep their women and children away from the danger.
Neanderthals ruled the world—till it started getting nice outside. About forty-five thousand years ago, the Long Winter ended and a hot front moved in. The forests shrank, leaving behind parched grasslands stretching to the horizon. The new climate was great for the Running Men; the antelope herds exploded and feasts of plump roots were pushing up all over the savannah.
The Neanderthals had it tougher; their long spears and canyon ambushes were useless against the fleet prairie creatures, and the big game they preferred was retreating deeper into the dwindling forests. Well, why didn’t they just adopt the hunting strategy of the Running Men? They were smart and certainly strong enough, but that was the problem; they were too strong. Once temperatures climb above 90 degrees Fahrenheit, a few extra pounds of body weight make a huge difference—so much so that to maintain heat balance, a 160- pound runner would lose nearly three minutes per mile in a marathon against a one hundred-pound runner. In a two-hour pursuit of a deer, the Running Men would leave the Neanderthal competition more than ten miles behind.
Smothered in muscle, the Neanderthals followed the mastodons into the dying forest, and oblivion. The new world was made for runners, and running just wasn’t their thing.
Privately, David Carrier knew the Running Man theory had a fatal flaw. The secret gnawed until it nearly turned him into a killer.
“Yeah, I was kind of obsessed,” he admitted when I met him at his lab in the University of Utah, twenty-five years and three academic degrees since his moment of inspiration at the dissecting table in 1982. He was now David Carrier, Ph.D., professor of biology, with gray in his push-broom mustache and rimless round glasses over his intense brown eyes. “I was dying to just grab something with my own two hands and say, ‘Look! Satisfied now?’”
The problem was this: Chasing an animal to death is evolution’s version of the perfect crime. Persistence hunting (as it’s known to anthropologists) leaves behind no forensics—no arrowheads, no spear-nicked deer spines—so how do you build a case that a killing took place when you can’t produce a corpse, a weapon, or witnesses? Despite Dr. Bramble’s physiological brilliance and Dr. Lieberman’s fossil expertise, there was no way they could prove that our legs were once lethal weapons if they couldn’t show that someone, somewhere, had actually run an animal to death. You can spout any theory you want about human performance (“We can suspend our own heartbeats! We can bend spoons with our brains!”) but in the end, you can’t make the shift from appealing notion to empirical fact if you don’t come up with the goods.
“The frustrating thing is, we were finding stories all over the place,” David Carrier said. Throw a dart at the map, and chances are you’ll bull’s-eye the site of a persistence-hunting tale. The Goshutes and Papago tribes of the American West told them; so did the Kalahari Bushmen in Botswana, the Aborigines in Australia, Masai warriors in Kenya, the Seri and Tarahumara Indians in Mexico. The trouble was, those legends were fourth-or fifth-hand at best; there was as much evidence to support them as there was that Davy Crockett kilt him a b’ar when he was only three.
“We couldn’t find anyone who’d done a persistence hunt,” David said. “We couldn’t find someone who’d even seen one.” No wonder the scientific community remained skeptical. If the Running Man theory was right, then at least one person on this planet of six billion should still be able to catch quarry on foot. We may have lost the tradition and necessity, but we should still have the native ability: our DNA hasn’t changed in centuries and is 99.9 percent identical across the globe, meaning we’ve all got the same stock parts as any ancient hunter-gatherer. So how come none of us could catch a stinking deer?
“That’s why I decided to do it myself,” David said. “As an under-grad, I got into mountain races and had a lot of fun at those. So when it came to how humans breathe differently when we run, I think it was easier for me to see how it could affect us as a species. The idea didn’t seem as strange to me as it would for someone who never left the lab.”
Nor did it seem strange to him that if he couldn’t find a caveman, he could become one. In the summer of 1984, David persuaded his brother, Scott, a freelance writer and reporter for National Public Radio, to go to Wyoming and help him catch a wild antelope. Scott wasn’t much of a runner, but David was in great shape and fiercely motivated by the lure of scientific immortality. Between him and his brother, David figured, it should take only two hours before eight hundred pounds of proof was flopping at his feet.
“We drive off the interstate and down a dirt road for a few miles and it’s a wide and open high desert of sagebrush, dry as a bone, mountains in every direction. There are antelope everywhere.” That’s how Scott later painted the scene for listeners on NPR’s This American Life. “We stop the car and start running after three—a buck and two does. They run very quickly, but for short distances, and then stop and stare at us till we catch up. Then they take off again. Sometimes they run a quarter of a mile, sometimes a half mile.”
Perfect! It was playing out exactly as David had predicted. The antelope weren’t getting enough time to cool off before David and Scott were yip-yip-yaahooing on their tails again. A few more miles of this, David figured, and he’d be heading back to Salt Lake with a trunk full of venison and a killer video to slap down on Dr. Bramble’s desk. His brother, on the other hand, sensed something very different going on.
“The three antelope look at me like they know exactly what we’re proposing, and they’re not the least bit worried,” Scott continues. It didn’t take him long to find out why they were so calm in the face of what should have been impending death. Instead of flopping over in exhaustion, the antelope pulled a shell game; when they got winded, they circled back and hid in the herd, leaving David and Scott no idea which antelopes were tired and which were fresh. “They blend and flow and change positions,” Scott says. “There are no individuals, but this mass that moves across the desert like a pool of mercury on a glass table.”
For two more days, the two brothers chased mercury balls across the Wyoming plains, never realizing they were in the midst of a magnificent mistake. David’s failure was unwitting proof of his own theory: human running is different from any other running on earth. You can’t catch other animals by copying them, and especially not by using the crude approximation of animal running we’ve preserved in sports. David and Scott were relying on instinct, strength, and stamina, without realizing that human distance running, at its evolutionary best, is much more than that; it’s a blend of strategy and skill perfected during millions of years of do-or-die decisions. And like any other fine art, human distance running demands a brain-body connection that no other creature is capable of.
But it’s a lost art, as Scott Carrier would spend the next decade discovering. Something strange happened out there on the Wyoming plains: the lure of the lost art got into Scott’s blood and wouldn’t let go. Despite the hopelessness of that expedition, Scott spent years researching persistence hunting on his brother’s behalf. He even created a nonprofit corporation devoted to finding the Last of the Long Distance Hunters, and recruited elite ultrarunner Creighton King—the Double Grand Canyon record holder before the Skaggs bros came along—to join an expedition to the Sea of Cortez, where word had it that a tiny clan of Seri Indians had preserved the link to our distance-running past.
Scott found the clan—but he found them too late. Two elders had learned old-style running from their father, but they were a half century out of practice and too old to even demonstrate.
That was the end of the trail. By 2004, the hunt for that one person in six billion had lasted twenty years and gone nowhere. Scott Carrier gave up. David Carrier had moved on long before, and was now studying physical-combat structures in primates. The Last of the Long Distance Hunters was a cold case.
Naturally, that’s when the phone rang.
“So, out of the blue, I find myself talking to this stranger,” Dr. Bramble begins. He looks like an old cowpoke, with his shaggy gray hair and crisp rancher’s shirt, and it’s a style that perfectly matches the dried animal skulls on the walls of his lab and his enthralling, gather-round-the-campfire storytelling. By 2004, Dr. Bramble says, the Utah-Harvard team had identified twenty-six distance-running markers on the human body. With little hope of ever finding the Last Hunter, they decided to go ahead and publish their findings anyway. Nature magazine put them on the cover, and a copy apparently made its way to a beach town on the South African coast, because that’s where this call was coming from.
“It’s not hard to run an antelope to death,” the stranger said. “I can show you how it’s done.”
“Sorry—who are you?”
“Louis Liebenberg. From Noordhoek.”
Bramble knew all the top names in the running-theory field, which wasn’t hard since they could fit around a diner booth. Louis Liebenberg from Noordhoek he’d never heard of.
“Are you a hunter?” Bramble asked.
“Me? No.”
“Oh … anthropologist?”
“No.”
“What’s your field?”
“Math. Math and physics.”
Math? “Uh … how did a mathematician run down an antelope?”
Bramble heard a snort of laughter. “By accident, mostly.”
It’s eerie how the lives of Louis Liebenberg and David Carrier spiraled each other for decades without either of them knowing it. Back in the early ’80s, Louis was also an undergraduate in college and, like David, he was suddenly electrified by an insight into human evolution that few others believed in.
Part of Louis’s problem was his expertise: he had none. At the time, he was barely twenty and majoring in applied mathematics and physics at the University of Cape Town. It was while taking an elective course in the philosophy of science that he started wondering about the Big Bang of the human mind. How did we leap from basic survival thinking, like that of other animals, to wildly complicated concepts like logic, humor, deduction, abstract reasoning, and creative imagination? Okay, so primitive man upgraded his hardware with a bigger brain—but where did he get the software? Growing a bigger brain is an organic process, but being able to use that brain to project into the future and mentally connect, say, a kite, a key, and a lightning bolt and come up with electrical transference was like a touch of magic. So where did that spark of inspiration come from?
The answer, Louis believed, was out in the deserts of southern Africa. Even though he was a city kid who knew jack about the outdoors, he had a hunch that the best place to look for the birth of human thought was the place where human life began. “I had a vague gut feeling that the art of animal tracking could represent the origin of science itself,” Louis says. Then who better to study than the Bushmen of the Kalahari Desert, who were both masters of animal tracking and living remnants of our prehistoric past?
So, at age twenty-two, Louis decided to drop out of college and write a new Chapter in natural history by testing his theory with the Bushmen. It was an insanely ambitious plan for a college dropout with zero experience in anthropology, wilderness survival, or scientific method. He spoke neither the Bushmen’s native tongue, !Kabee, nor their adopted one, Afrikaans. He didn’t even know anything about animal tracking, the reason he was going in the first place. But so what? Louis shrugged, and got to work. He found an Afrikaans translator, made contact with hunting guides and anthropologists, and eventually set off down the Trans-Kalahari Highway into Botswana, Namibia … and the unknown.
Like Scott Carrier, Louis soon discovered that he was losing a race against time. “I went village to village looking for Bushmen who hunt with bow and arrow, since they’d have the tracking skills,” Louis says. But with big-game safaris and ranchers taking over their old game lands, most of the Bushmen had abandoned the nomadic life and were living on government settlements. Their decline was heartbreaking; instead of roaming the wilderness, many of the Bushmen were surviving on slave wages for farm jobs and seeing their sisters and daughters recruited by truck-stop bordellos.
Louis kept searching. Far out in the Kalahari, he finally came across a renegade band of Bushmen who, he says, “stubbornly clung to freedom and independence and wouldn’t subject themselves to manual labor or prostitution.” As it turned out, the search for One in Six Billion was just about mathematically correct: in all the Kalahari, only six true hunters remained.
The renegades agreed to let Louis hang around, an offer he took to the extreme; once installed, Louis acted like an unemployed in-law, basically squatting with the Bushmen for the next four years. The city kid from Cape Town learned to live on the Bushman diet of roots, berries, porcupine, and ratlike springhares. He learned to keep his campfire burning and tent zipped even on the most sweltering nights, since packs of hyenas were known to drag people from open shelters and tear out their throats. He learned that if you stumble upon an angry lioness and her cubs, you stand tall and make her back down, but in the same situation with a rhino, you run like hell.
When it comes to mentors, you can’t beat survival; just trying to fill his belly every day and avoid pissing off, for instance, two black-backed jackals mating beneath a baobob was an excellent way for Louis to begin absorbing the wizardry of a master tracker. He learned to look at piles of zebra dung and distinguish which droppings came from which animal; intestines, he discovered, have ridges and grooves that leave unique patterns on feces. Learn to tell them apart, and you can single out a zebra from an exploding herd and track it for days by its distinctive droppings. Louis learned to hunch over a set of fox tracks and re-create exactly what it was doing: here, it was moving slowly as it scented around for mice and scorpions, and look, that’s where it trotted off with something in its mouth. A swirl of swept dirt told him where an ostrich had taken a dust bath, and let him backtrack to find its eggs. Meerkats make their warrens in hard-pan, so why were they digging here in soft sand? Must mean there’s a den of tasty scorpions….
Even after you learn to read dirt, you ain’t learned nothing; the next level is tracking without tracks, a higher state of reasoning known in the lit as “speculative hunting.” The only way you can pull it off, Louis discovered, was by projecting yourself out of the present and into the future, transporting yourself into the mind of the animal you’re tracking. Once you learn to think like another creature, you can anticipate what it will do and react before it ever acts. If that sounds a little Hollywood, then you’ve seen your share of movies about impossibly clairvoyant FBI profilers who can “see with the eyes of a killer.” But out there on the Kalahari plains, mind-throwing was a very real and potentially deadly talent.
“When tracking an animal, one attempts to think like an animal in order to predict where it is going,” Louis says. “Looking at its tracks, one visualizes the motion of the animal and feels that motion in one’s own body. You go into a trancelike state, the concentration is so intense. It’s actually quite dangerous, because you become numb to your own body and can keep pushing yourself until you collapse.”
Visualization … empathy … abstract thinking and forward projection: aside from the keeling-over part, isn’t that exactly the mental engineering we now use for science, medicine, the creative arts? “When you track, you’re creating causal connections in your mind, because you didn’t actually see what the animal did,” Louis realized. “That’s the essence of physics.” With speculative hunting, early human hunters had gone beyond connecting the dots; they were now connecting dots that existed only in their minds.
One morning, four of the renegade Bushmen—!Nate, !Nam!kabe, Kayate, and Boro/xao—woke Louis up before dawn to invite him on a special hunt. Don’t eat any breakfast, they warned him, and drink all the water you can hold. Louis downed a mug of coffee, grabbed his boots, and fell in behind the hunters as they marched off across the savannah in the dark. The sun rose until it was broiling over their heads, but the hunters pushed on. Finally, after walking nearly twenty miles, they spotted a clutch of kudu, an especially agile form of antelope. That’s when the Bushmen started to run.
Louis stood there, confused. He knew the standard Bushman bow-hunting drill: drop to your belly, creep into arrow range, let fly. So what the hell was this all about? He’d heard a little about persistence hunts, but he ranked them somewhere between an accident and a lie: either the animal had actually broken its neck while fleeing, or the story was out-and-out baloney. No way these guys were going to catch one of those kudus on foot. No way. But the more he said “No way,” the farther away the Bushmen got, so Louis quit thinking and started running.
“This is how we do it,” !Nate said when a panting Louis caught up. The four hunters ran swiftly but easily behind the bounding kudu. Whenever the animals darted into an acacia grove, one of the hunters broke from the group and drove the kudu back into the sun. The herd would scatter, re-form, scatter again, but the four Bushmen ran and swerved behind a single kudu, cutting it out of the herd whenever it tried to blend, flushing it from the trees whenever it tried to rest. If they had a doubt about which one to chase, they dropped to the ground, checked the tracks, and adjusted their pursuit.
As he gasped along behind the band, Louis was surprised to find !Nate, the strongest and most skilled hunter of the renegade Bushmen, hanging back with him. !Nate wasn’t even carrying a canteen like the other hunters. Nearly ninety minutes into the pursuit, Louis discovered why: when one of the older hunters tired and dropped out, he handed his canteen to !Nate. !Nate drank it dry, then traded it for a half-full one when a second runner dropped out.
Louis staggered along behind, determined to see the hunt through to the end. He was bitterly regretting his choice of heavy bush boots; the Bushmen traditionally wore light, giraffe-skin moccasins, and now had on thin, flimsy sneakers that let their feet cool on the fly. Louis felt the way the kudu looked; he watched it weave drunkenly … its front knees buckled, straightened … it recovered and bounded away … then crashed to the ground.
So did Louis. By the time he got to the fallen kudu, he was so overheated he’d stopped sweating. He pitched facedown into the sand. “When you’re focused on the hunt, you push to the limits. You’re not aware you’re exhausted,” Louis later explained. In a way, he’d triumphed; Louis had managed to cross over and run as hard as if he were the one being pursued. Where he failed was not knowing to check his own footprints; because it’s so easy to become numb to your own vital signs, the Bushmen learned long ago to periodically check their own tracks. If their prints looked as bad as the kudu’s, they’d stop, wash their faces, hold a mouthful of water and slowly let it trickle down their throats. After the final swallow, they’d walk and check their tracks again.
Louis’s head was pounding and his dry eyes were going blurry. He was barely conscious, but still alert enough to be really scared; he was lying in the desert in 107- degree heat, and he knew he had only one chance to save his life. He fumbled for his belt knife and reached toward the dead kudu. If he could slash it open, he could suck the water from its stomach.
“NO!” !Nate stopped Louis. Unlike other antelopes, kudus eat acacia leaves, which are poisonous for humans. !Nate calmed Louis, told him to hold on a little longer, and took off running: even though !Nate had already hiked twenty miles and run fifteen, he was able to run twelve more miles to bring Louis back some water. !Nate wouldn’t let him drink it. First, he rinsed Louis’s head, then he washed his face, and only after Louis’s skin began to cool did !Nate allow him tiny sips.
Later, after !Nate had helped him back to camp, Louis marveled at the ruthless efficiency of the persistence hunt. “It’s much more efficient than a bow and arrow,” he observed. “It takes a lot of attempts to get a successful hunt by bow. You can hit the animal and still lose it, or scavengers can smell blood and get to it before you do, or it can take all night for the poison on the arrow tips to work. Only a small percentage of arrow shots are successful, so for the number of days hunting, the meat yield of a persistence hunt is much higher.”
Louis found out only in his second, third, and fourth persistence hunts how lucky he’d gotten in the first; that debut kudu dropped after only two hours, but every one after that kept the Bushmen on the run for three to five hours (neatly corresponding, one might note, to how long it takes most people to run our latter-day version of prehistoric hunting, the marathon. Recreation has its reasons).
To succeed as a hunter, Louis had to reinvent himself as a runner. He’d been an excellent middle-distance athlete in high school, winning the 1,500- meter championship and finishing a close second in the 800, but to hang with the Bushmen, he had to forget everything he’d been taught by modern coaches and study the ancients. As a track athlete, he’d drop his head and hammer, but as an apprentice Bushman, he had to be eyes high and tinglingly alert every step of the way. He couldn’t zone out and ignore pain; instead, his mind was constantly tap-dancing between the immediate—scratches in the dust, sweat on his own forehead—and the imaginary, as he played mental war games to think one step ahead of his prey.
The pace wasn’t too fierce; the Bushmen average about ten minutes a mile, but many of those miles are in soft sand and brush, and they occasionally stop to study tracks. They’d still fire the jets and take off at a sprint, but they knew how to keep trotting afterward and recover on the run. They had to, because a persistence hunt was like showing up at the starting line without knowing if you were running a half marathon, marathon, or ultra. After a while, Louis began to look at running the way other people look at walking; he learned to settle back and let his legs spin in a quick, easy trot, a sort of baseline motion that could last all day and leave him enough reserves to accelerate when necessary.
His eating changed, too. As a hunter-gatherer, you’re never off the clock; you can be walking home after an exhausting day of collecting yams, but if fresh game scuttles into view, you drop everything and go. So Louis had to learn to graze, eating lightly throughout the day rather than filling up on big meals, never letting himself get thirsty, treating every day as if he were in a race that had already started.
The Kalahari summer cooled into winter, but the hunts continued. The Utah-Harvard docs would turn out to be wrong about one part of their Running Man theory: persistence hunting doesn’t depend on killer heat, because the ingenious Bushmen had devised ways to run down game in every weather. In the rainy season, both the tiny duiker antelope and the giant gemsbok, with its lancelike horns, would overheat because the wet sand splayed their hooves, forcing their legs to churn harder. The four-hundred-pound red hartebeest is comfortable in waist-high grasslands, but exposed and vulnerable when the ground parches during dry winters. Come the full moon, antelopes are active all night and tired by daybreak; come spring, they’re weakened by diarrhea from feasting on green leaves.
By the time Louis was ready to head home from the bush and begin writing The Art of Tracking: The Origin of Science, he’d gotten so accustomed to epic runs that he almost took them for granted. He barely mentions running in his book, focusing more on the mental demands of the hunt than the physical. It was only after a copy of Nature magazine fell into his hands that he fully appreciated what he’d seen out there in the Kalahari, and grabbed the phone to dial Utah.
Know why people run marathons? he told Dr. Bramble. Because running is rooted in our collective imagination, and our imagination is rooted in running. Language, art, science; space shuttles, Starry Night, intravascular surgery; they all had their roots in our ability to run. Running was the superpower that made us human—which means it’s a superpower all humans possess.
“Then why do so many people hate it?” I asked Dr. Bramble as he came to the end of the story of Louis and the Bushmen. “If we’re all born to run, shouldn’t all of us enjoy it?”
Dr. Bramble began his answer with a riddle. “This is fascinating stuff,” he said. “We monitored the results of the 2004 New York City Marathon and compared finishing times by age. What we found is that starting at age nineteen, runners get faster every year until they hit their peak at twenty-seven. After twenty-seven, they start to decline. So here’s the question—how old are you when you’re back to running the same speed you did at nineteen?”
All righty. I flipped my notebook to a blank page and started jotting numbers. It takes eight years until you run your best time at age twenty-seven. If you get slower at the same rate you got faster, then you’d be back at your nineteen-year-old time by age thirty-six: eight years up, eight years down. But I knew there was a twist involved, and I was pretty sure it had to be whether we fade away as quickly as we improve. “We probably hang on to our speed a little longer once we get it,” I decided. Khalid Khannouchi was twenty-six when he broke the marathon world record, and was still fast enough at thirty-six to finish in the top four at the 2008 U.S. Olympic trials. He’d lost only ten minutes in ten years, despite a ton of injuries. In honor of the Khannouchi Curve, I bumped my answer up to forty.
“Forty—,” I started to say, until I saw the smile creasing Bramble’s face. “Five,” I hastily added. “I’ll guess forty-five.”
“Wrong.”
“Fifty?”
“Nope.”
“It can’t be fifty-five.”
“You’re right,” Bramble said. “It can’t be. It’s sixty-four.”
“Are you serious? That’s a—” I scribbled out the math. “That’s a forty-five-year difference. You’re saying teenagers can’t beat guys three times their age?”
“Isn’t that amazing?” Bramble agreed. “Name any other field of athletic endeavor where sixty-four-year-olds are competing with nineteen-year-olds. Swimming? Boxing? Not even close. There’s something really weird about us humans; we’re not only really good at endurance running, we’re really good at it for a remarkably long time. We’re a machine built to run—and the machine never wears out.”
You don’t stop running because you get old, the Dipsea Demon always said. You get old because you stop running….
“And it’s true for both genders,” Dr. Bramble continued. “Women show the same results as men.” That makes sense, since a curious transformation came over us when we came down from the trees: the more we became human, the more we became equal. Men and women are basically the same size, at least compared with other primates: male gorillas and orangutans weigh twice as much as their better halves; male chimps are a good one-third bigger than females; but between the average human him and the average human her, the difference in bulk is only a slim 15 percent. As we evolved, we shucked our beef and became more sinuous, more cooperative … essentially, more female.
“Women have really been underrated,” Dr. Bramble said. “They’ve been evolutionarily shortchanged. We perpetuate this notion that they were sitting around waiting for the men to come back with food, but there’s no reason why women couldn’t be part of the hunting party.” Actually, it would be weird if women weren’t hunting alongside the men, since they’re the ones who really need the meat. The human body benefits most from meat protein during infancy, pregnancy, and lactation, so why wouldn’t women get as close to the beef supply as possible? Hunter-gatherer nomads shift their camps by the movements of the herds, so instead of hauling food back to camp, it made more sense for the whole camp to go to the food.
And caring for kids on the fly isn’t that hard, as American ultra-runner Kami Semick demonstrates; she likes to run mountain trails around Bend, Oregon, with her four-year-old daughter, Baronie, riding along in a backpack. Newborns? No problem: at the 2007 Hardrock 100, Emily Baer beat ninety other men and women to finish eighth overall while stopping at every aid station to breast-feed her infant son. The Bushmen are no longer nomadic, but the equal-partners-in-hunting tradition still exists among the Mbuti Pygmies of the Congo, where husbands and wives with nets pursue the giant forest hog side by side. “Since they are perfectly capable of giving birth to a child while on the hunt, then rejoining the hunt the same morning,” notes anthropologist Colin Turnbull, who’s spent years among the Mbuti, “mothers see no reason why they should not continue to participate fully”
Dr. Bramble’s picture of the past was taking on clarity and color. I could see a band of hunters—young and old, male and female—running tirelessly across the grasslands. The women are up front, leading the way toward fresh tracks they spotted while foraging, and hard behind are the old men, their eyes on the ground and their minds inside a kudu skull a half mile ahead. Crowding their heels are teens eager to soak up tips. The real muscle hangs back; the guys in their twenties, the strongest runners and hunters, watching the lead trackers and saving their strength for the kill. And bringing up the rear? The Kami Semicks of the savannah, toting their kids and grandkids.
After all, what else did we have going for us? Nothing, except we ran like crazy and stuck together. Humans are among the most communal and cooperative of all primates; our sole defense in a fang-filled world was our solidarity, and there’s no reason to think we suddenly disbanded during our most crucial challenge, the hunt for food. I remembered what the Seri Indians told Scott Carrier after the sun had set on their persistence-hunting days. “It was better before,” a Seri elder lamented. “We did everything as a family. The whole community was a family. We shared everything and cooperated, but now there is a lot of arguing and bickering, every man for himself.”
Running didn’t just make the Seris a people. As Coach Joe Vigil would later sense about his own athletes, it also made them better people.
“But there’s a problem,” Dr. Bramble said. He tapped his forehead. “And it’s right up here.” Our greatest talent, he explained, also created the monster that could destroy us. “Unlike any other organism in history, humans have a mind-body conflict: we have a body built for performance, but a brain that’s always looking for efficiency.” We live or die by our endurance, but remember: endurance is all about conserving energy, and that’s the brain’s department. “The reason some people use their genetic gift for running and others don’t is because the brain is a bargain shopper.”
For millions of years, we lived in a world without cops, cabs, or Domino’s Pizza; we relied on our legs for safety, food, and transportation, and it wasn’t as if you could count on one job ending before the next one began. Look at !Nate’s wild hunt with Louis; !Nate sure wasn’t planning on a fast 10k immediately after a half-day hike and a high-speed hunt, but he still found the reserve energy to save Louis’s life. Nor could his ancestors ever be sure that they wouldn’t become food right after catching some; the antelope they’d chased since dawn could attract fiercer animals, forcing the hunters to drop lunch and run for their lives. The only way to survive was to leave something in the tank—and that’s where the brain comes in.
“The brain is always scheming to reduce costs, get more for less, store energy and have it ready for an emergency,” Bramble explained. “You’ve got this fancy machine, and it’s controlled by a pilot who’s thinking, ‘Okay, how can I run this baby without using any fuel?’ You and I know how good running feels because we’ve made a habit of it.” But lose the habit, and the loudest voice in your ear is your ancient survival instinct urging you to relax. And there’s the bitter irony: our fantastic endurance gave our brain the food it needed to grow, and now our brain is undermining our endurance.
“We live in a culture that sees extreme exercise as crazy,” Dr. Bramble says, “because that’s what our brain tells us: why fire up the machine if you don’t have to?”
To be fair, our brain knew what it was talking about for 99 percent of our history; sitting around was a luxury, so when you had the chance to rest and recover, you grabbed it. Only recently have we come up with the technology to turn lazing around into a way of life; we’ve taken our sinewy, durable, hunter-gatherer bodies and plunked them into an artificial world of leisure. And what happens when you drop a life-form into an alien environment? NASA scientists wondered the same thing before the first space flights. The human body had been built to thrive under the pressure of gravity, so maybe taking away that pressure would act as an escape-trajectory Fountain of Youth, leaving the astronauts feeling stronger, smarter, and healthier. After all, every calorie they ate would now go toward feeding their brains and bodies, instead of pushing up against that relentless downward pull—right?
Not by a long shot; by the time the astronauts returned to earth, they’d aged decades in a matter of days. Their bones were weaker and their muscles had atrophied; they had insomnia, depression, acute fatigue, and listlessness. Even their taste buds had decayed. If you’ve ever spent a long weekend watching TV on the sofa, you know the feeling, because down here on earth, we’ve created our own zero-gravity bubble; we’ve taken away the jobs our bodies were meant to do, and we’re paying for it. Nearly every top killer in the Western world—heart disease, stroke, diabetes, depression, hypertension, and a dozen forms of cancer—was unknown to our ancestors. They didn’t have medicine, but they did have a magic bullet—or maybe two, judging by the number of digits Dr. Bramble was holding up.
“You could literally halt epidemics in their tracks with this one remedy,” he said. He flashed two fingers up in a peace sign, then slowly rotated them downward till they were scissoring through space. The Running Man.
“So simple,” he said. “Just move your legs. Because if you don’t think you were born to run, you’re not only denying history. You’re denying who you are.”