At first glance the annual Man vs. Horse Marathon, set for June 9 in Wales, seems like a joke sport brought to us by the same brilliant minds behind dwarf tossing and gravy wrestling. It was, after all, the product of a pints-fueled debate in a Welsh pub, and for years its official starter was rock musician Screaming Lord Sutch, founder of the Official Monster Raving Loony Party. But the jokiness is misleading: When viewed through science’s clarifying lens, the funny marathon is one of the few sports that isn’t a joke.
Hear me out, sports fans—I'm a basketball nut myself, and so the joke is as much on me as anyone. To see where I’m coming from, you can’t do better than examining basketball’s most physically talented player, Michael Jordan. He was hailed as nearly repealing the law of gravity, and during his prime he made rival players look as if they were moving in slow motion. But Air Jordan wasn't in the same league as a house cat when it comes to leaping. Consider how casually young cats can jump up onto refrigerators. To match that, a man would have to do a standing jump right over the backboard. And a top-notch Frisbee dog corkscrewing through the air eight feet up to snag a whizzing disc makes Jordan look decidedly human when it comes to the fantastic quickness, agility, strength, and ballistic precision various animals are endowed with.
There's no denying it—our kind started substituting brains for brawn long ago, and it shows: We can't begin to compete with animals when it comes to the raw ingredients of athletic prowess. Yet being the absurdly self-enthralled species we are, we crowd into arenas and stadiums to marvel at our pathetic physical abilities as if they were something special. But there is one exception to our general paltriness: We're the right honorable kings and queens of the planet when it comes to long-distance running.
The Wales marathon has helped demonstrate that. Its originator was a Welsh pub owner named Gordon Green. One day in 1979 he got into an argument with an equestrian friend about the relative strengths of men and horses as distance runners. Green insisted a human could beat a horse in a long race, and to prove his point he helped instigate the marathon in 1980. For the next 24 years, he found himself losing the argument as riders on horseback left human runners behind. But then it finally happened—in 2004 a British man named Huw Lobb won. Three years later Germany’s Florian Holzinger outran the horses, as did one other human contestant. The media loved it—a predictable farce had become a man-bites-dog story. Bookies were less enthused; they had to pay out on bets made at 16-to-1 odds favoring the horses.
The oddsmakers would have known better if they'd been following the work of Harvard anthropologist Daniel Lieberman and University of Utah biologist Dennis Bramble. They jointly proposed in a 2004 paper that we're superlatively endowed by evolution to go long. Our long-striding legs are packed with springlike tendons, muscles, and ligaments that enable us to briefly store elastic energy as we come down on a foot and then recoil to help propel us forward. Tellingly, the most important of these springs, our big, strong Achilles tendons, aren’t found in early human precursors such as Australopithecus—it seems that the high-end tendons evolved along with other adaptations for distance running in the genus Homo when it appeared on the African savannah about 2 million years ago.
We’ve inherited large leg and foot joints from those ancestors, which spread out high forces that must be absorbed when running. To help ensure stability on two legs, we have big gluteus maximus muscles. (Chimps, which are incapable of distance running, have comparatively tiny butts.) Our clever torsos are designed to "counter-rotate" versus the hips as we run, also aiding stability. And we have an unusually large percentage of fatigue-resistant, slow-twitch muscle fibers, which make for endurance rather than speed. By contrast, most animals are geared for sprinting because they’re either predators that chase or prey that run away, and their muscles thus have much higher percentages of fast-twitch fibers than ours. (Cheetahs' hind-leg muscles are the fast-twitch-richest of all.)
But what most sets us apart as runners is that we’re really cool—we naked apes are champion sweaters and can dissipate body heat faster than any other large mammal. Our main rivals for the endurance-running crown fall into two groups: migratory ungulates, such as horses and wildebeest, and social carnivores, such as dogs and hyenas. They can easily out-sprint us by galloping. But none can gallop very far without overheating—they largely rely on panting to keep cool, and they can't pant when galloping, for panting involves taking very rapid, shallow breaths that would interfere with respiration when running. Dogs can gallop for only about 10 to 15 minutes before reverting to a trot, and so their distance-running speed tops out at about 3.8 meters per second. Horses' average distance-running speed is 5.8 meters per second—a canter. Wildebeests’ is 5.1 meters per second.