When early humans stood erect over the African savannah, our improved vantage point gave more than views of prey and predator, berry bush and honeybee hive, nut tree and watering hole; we saw possibilities. We saw the horizon stretching out until what appeared to be infinity. We saw sunsets and sunrises, mountains and valleys, stars and constellations and galaxies. The world grew. And we viewed this massive world with a childlike curiosity that made just looking insufficient. We had to touch, visit, and experience it.
So we walked .
Some of us walked north from our East African homelands across the Levantine corridor  to reach the Near East (or what became the Fertile Crescent before agriculture stripped it bare). From there, humans walked deeper into the new land, some heading south into the Indian subcontinent, others exploring the far reaches of the east or the steppes of central Asia and on into Europe.
Other African groups spread south and west across the rest of the continent or, taking advantage of low water levels, crossed the Red Sea at the Horn of Africa, alternately walking and perhaps rafting along Asia’s southern coastline until Indonesia and, eventually, Australia.
And at some point, humans walked clear across the Arctic land bridge to North America. A few of us settled in that far north, happy with walrus and seal and salmon . Others kept walking, making their way through Canada, America, and down on into Latin America.
Walking was freedom. There was always something else just around the bend, a new life, a new beginning, new plants and animals to eat (and eventually tame). If things got awkward or a conflict arose within a group, people could always walk away . There were no borders or boundaries to respect, no real estate to guard. Life wasn’t exactly easy or idyllic, but we had options. We always had a way out if we were willing to walk.
And when we’d stay and explore an area, ingratiate ourselves with the new surroundings, get comfortable – we didn’t stop walking. We didn’t hunker down, lay down roots, confine ourselves to a plot of land, and get fat. After all, we were hunter gatherers, largely nomadic, who went where the food went and grew.
We walked short distances. A few hundred yards to gather kindling and wood for the morning fire. We walked a mile at midday to fetch water and maybe gather some nuts and tubers. We walked to the watering hole to wait for thirsty game; if successful, we walked back to camp carrying our prize. If modern foragers like the Ache or Hadza are any indication (PDF ), we walked anywhere from 6 to 16 kilometers on an average day. And our short distance walking was spread throughout the day, not clumped together in a single uninterrupted session on the treadmill  after work.
We walked under load. We carried armfuls and baskets and skins of tubers , nuts , fruits , and the rare honeycomb. We hauled butchered animal parts  and piles of shellfish , small game and fish . We carried children . Shopping carts, strollers, and delivery services were unavailable.
We walked on uneven terrain. The natural world isn’t flat and linear  and made of concrete. There are gradations. Roots and rocks jut out and must be avoided or surmounted. Every step is different than the last, and this makes walking on uneven terrain far more energetically demanding than walking on flat terrain , and far better at improving and maintaining balance, physical fitness, and metabolic health .
We walked kind of funny, unlike any other bipedal animal, most of whom have tails to counterbalance. We stand atop two relatively small feet and we’re tall, so we’re constantly teetering to one side or the other and making infinitesimally small corrections to stay upright that we don’t even notice we’re making. Walking is falling forward and swinging a leg out to catch ourselves before we faceplant. It’s most evident in babies who have mastered the “falling” part without figuring out the “swing your leg out” part. But we all do it – athletes, hikers, mallrats, seniors. If we’re walking, we’re falling and catching ourselves.
And yet as silly as it sounds, this funny way of walking worked for us. So well that constant, frequent walking and humanhood are inseparable. One and the same. Our genome has developed in the context of frequent walking . To be human is to walk:
We’re bipedal. We have two free hands to carry supplies, tools, food, water, weapons as we walk; we have opposable thumbs and brains of sufficient capability to fashion packs, ropes, lashes for carrying, pulling, dragging even more supplies, tools, food, water, weapons along.
We’re upright and relatively hairless. The sun hits us at an angle rather than directly head-on, keeping us cooler than a quadruped whose back is fully exposed. We also thermoregulate by sweating through glands that line our skin’s surface. Improved thermoregulation lets us walk greater distances without overheating.
We’re heel-strikers. Aside from bears and great apes, every other animal walks on its toes. Humans lead with the heel and roll to the toes when we walk, maximizing our walking economy  and allowing us to cover great distances without getting winded or expending much energy.
This perfect storm of anatomy, anthropometry, and biology made us obligate walkers so that even as food sources changed, as stalks of wheat and fences shot up around us, as nomadism gave way to agrarianism gave way to urbanism, humans used controlled falling as our primary mode of transportation. Neolithic farmers walked. Medieval peasants walked. Mayan warriors walked. Slaves, monks, artisans, fish mongers, cobblers, Union soldiers all walked. Victorian-era laborers walked an average of six miles a day . Modern Amish, a decent proxy for pre-industrial agrarian people, still walk nearly 15,000 steps (females aged 18-75) and 19,000 steps (males aged 18-75) per day (PDF ). We have to walk.
It’s only in the information age – this world of Amazon same day deliveries and digital libraries in our pockets and car-dependent suburban sprawl and obese toddlers and anti-sitting  campaigns – that we’ve stopped walking . But the need to walk has never left.
The human story is a story of constant movement, of progress, of yearning and seeking and exploring. Underneath all that is the simple physical act of putting one foot in front of the other. Without the controlled falling, the other stuff doesn’t matter so much or work so well.
Henry David Thoreau couldn’t  “preserve [his] health and spirits” without spending “four hours a day at least – and commonly more than that – sauntering through the woods and over the hills and fields, absolutely free from all worldly engagements.” He is not alone. We can’t all achieve that level of sauntering, but I’m certain we can do a whole lot better than the amount we currently engage in. Those walking  genes, those urges to explore remain within us. We should honor, respect, and indulge them.
I’d tell you to go for a walk or to take a hike, but that’s not good enough. Go for walks. Take hikes, as many as you can squeeze in. Continue the human story.
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