by Robert Moor
“We say the cows laid out Boston,” wrote Emerson, in reference to the (probably apocryphal) belief that the city’s crooked grid was the result of paving old cow paths. “Well, there are worse surveyors. Every pedestrian in our pastures has frequent occasion to thank the cows for cutting the best path through the thicket, and over the hills: and travelers and Indians know the value of a buffalo-trail, which is sure to be the easiest possible pass through the ridge.” More than a hundred years later, a study from the University of Oregon has lent credence to Emerson’s claim: forty cattle were pitted against a sophisticated computer program and tasked to find the most efficient path across a field. In the end, the cows outperformed the computer by more than ten percent.
Before colonization, many North American tribes followed deer and bison trails, which found the lowest passes across mountain ranges and the shallowest fords across rivers. Elephants, too, are thought to have cleared the most expedient roads through many parts of India and Africa. Nonhuman animals achieve this efficient design not through superhuman intelligence, but through sheer persistence. They continually search for better routes, and once one is found, they adopt it. In this manner, trail networks of incredible efficiency can arise simply, organically, iteratively, without any forethought necessary.
A clever and patient observer can watch a trail sleeken in real time. The physicist Richard Feynman, for instance, witnessed this phenomenon while studying the ants that infested his home in Pasadena. One afternoon, he took note of a line of ants walking around the rim of his bathtub. Though myrmecology was far from his area of expertise, he was curious to find out why ant trails inevitably “look so straight and nice.” First, he placed a lump of sugar on the far side of the bathtub and waited for hours until an ant found it. Then, as the ant carted a piece of the sugar back to its nest, Feynman picked up a colored pencil and traced the ant’s return path along the bathtub. The resulting trail was “quite wiggly,” full of errors.
Another ant emerged, followed the first ant’s trail, and located the sugar. As it plodded back to the nest, Feynman marked its trail with a different color of pencil. But in its haste to return with its bounty, the second ant repeatedly lost the first ant’s trail, cutting off many of the unnecessary curves: The second line was noticeably straighter than the first. The third line, Feynman noted, was even straighter than the second. He ultimately followed as many as ten ants with his pencils, and, as he’d expected, the last few trails he traced formed a neat line along the bathtub’s edge. “It’s something like sketching,” he observed. “You draw a lousy line at first; then you go over it a few times and it makes a nice line after a while.”
I later learned that this streamlining process extended beyond ants, or even animals. “All things optimize in nature, to some degree,” an entomologist named James Danoff-Burg told me.
Intrigued, I asked him if there was a good book I could read on optimization.
“Sure,” he said. “It’s called The Origin of Species by Charles Darwin.”
Evolution, he explained, is a form of long-term, genetic optimization; the same process of trial and error takes place. And, as Darwin showed, in the great universal act of streamlining, even the errors are essential. If some ants weren’t error-prone, the ant trail would never straighten out. The scouts may be the genius architects who blaze the trails, but any rogue worker can be the one who stumbles upon a shortcut. Everyone optimizes, whether we are pioneering or perpetuating, making rules or breaking them, succeeding or screwing up.
After three and a half months I reached the base of Mount Washington in New Hampshire. I climbed it via the Crawford Path, the same trail I had hiked when I was ten. In rapid succession I pieced together a half-dozen peaks that I’d climbed at different times in the past decade: the Presidentials, Old Speck, Sugarloaf, Baldpate, the Bigelows. The order of the mountains sometimes surprised me; it was as if someone had opened my childhood photo album and rearranged my memories. The mountains also seemed smaller than I remembered. Hikes that had taken days when I was a kid now took only hours. It was an eerie sensation—that same uncanny, gargantuan feeling you get from revisiting your old kindergarten.
Any feeling of mastery I harbored was mingled with feelings of humility. I had hiked two thousand miles, but I could never have gotten there on my own. My route had been carved out by scores of volunteer trail-builders and a continuous flow of prior walkers.
I often felt this way on the trail: I was able to hold both one notion and its direct opposite in my mind at the same time. Paths, in their very structure, foster this way of thinking. They blear the divide between wilderness and civilization, leaders and followers, self and other, old and new, natural and artificial. It is fitting that in Mahayana Buddhism, the image of the Middle Path—and not some other metaphor—is used as a symbol of dissolving all dualities. The only binary that ultimately matters to a trail is the one between use and disuse—the continual, communal process of making sense, and the slow entropic process by which it is unmade.
On August 15, almost five months to the day after I had started out from Springer Mountain, I reached the summit of Mount Katahdin in Maine. Far below, in every direction, were green forests and blue lakes and islands of green forest within the blue of the lakes. After what felt like months of steady rain, the skies had finally cleared. I could feel the dampness baking from my bones. I had at last reached the trail’s end.
In the center of the peak was an iconic wooden sign announcing the trail’s northern terminus. It had the air of a shrine. Groups of day hikers hung back from it, forming a respectful half-circle, while a handful of thru-hikers approached it, one by one, with looks of reverence and tamped expectation. Each hiker had a moment alone with the sign, posed for a photograph to commemorate the occasion—some exuberant, some somber—and then moved on, allowing the next hiker to approach.
When my turn came, I walked up to the sign, laid my hands on it, and kissed its wind-scoured surface. The moment held a certain surreal quality; I already had imagined it a thousand times. My friends and I popped a bottle of cheap champagne, which we shook and sprayed in fanning arcs into the air. When we finally took a sip, the champagne had already gone flat and warm. That was a rough analog for how it felt to finish the trail: buzzy and yet weirdly dull. After five months, it was over.
And yet, when I moved back to New York City, I found that I continued to look at the world with the eyes of a thru-hiker. After almost half a year spent in mountainous wilderness, the city seemed at once a marvel and a monstrosity. It was hard to imagine a space more thoroughly transformed by human hands. What struck me most, though, was its rigidity: straight lines, right angles, cement roads, concrete walls, steel beams, harsh rules regulated by force. Waste was rampant; everything broke. The trail had taught me that good designs—like age-old tools and classic folktales—are trail-wise: They fulfill a common need by balancing efficiency, flexibility, and durability. They streamline. They self-reinforce. They bend but do not break. So much of our built environment, by comparison, seemed terribly, perilously inelegant.
Meanwhile, everywhere I looked, I noticed new trails: a desire line winding through a tiny park beside the East River, a line of ants inching along my windowsill. I noticed how the shoes of passing commuters wore greasy lines into the concrete of the subway platform, how spots of blackened chewing gum and flattened cigarette butts marked the entrance to nightclubs. Reading omnivorously, I discovered trails running thick through works of literature, history, ecology, biology, psychology, and philosophy. Then I put the books down and walked some more, seeking out fellow travelers—trail-walkers and trail-builders, hunters and herders, entomologists and ichnologists, geologists and geographers, historians and systems theorists—in the hopes of gleaning some common truths from their diverse fields of expertise.
Somewhere along the way I realized that at the heart of my thinking lay a simple
idea: A trail sleekens to its end. An explorer finds a worthwhile destination; then every walker who follows that trail makes it a little better. Ant trails, game paths, ancient ways, modern hiking trails—they all continually adapt to the aims of their walkers. Hurried walkers make straighter paths and leisurely walkers make curvier ones, just as some societies seek to maximize profit, while others strive to maximize equality, or military might, or gross national happiness.
The path of a runner often diverges from that of a walker, because, though both may be headed to the same place, they do so with differing priorities. A New Zealand sheep farmer named William Herbert Guthrie-Smith once observed that horse trails in open country will gradually straighten out. However, he noticed that this only took place in areas where the horses were allowed to trot, canter, or gallop. At a slow walk, the horses gladly followed each turn of a sinuous trail, minimizing their work by bending with the contours of the topography. When they sped up, they began to cut the inside corners off the curves, straightening them. If the horses had been allowed to run “at racing speed,” Guthrie-Smith believed they would “in time rule out paths almost perfectly straight.”
The lesson to be found here is not just that the trail of a galloping horse streamlines. It is that both the fast horse and the slow one seek the path of least resistance. When aims differ, trails do too. These overlapping and crisscrossing trails, created by countless living beings pursuing their own ends, form the planet’s warp and woof.
This book is the culmination of many years of research and many miles of walking. Throughout, I was fortunate to have been guided by experts in their fields, each illuminating a key element in the long history of trails, spanning from the Precambrian to the postmodern. In the first chapter, we take a close look at the world’s oldest fossil trails, and explore the question of why animals first began to move. The second chapter investigates how insect colonies create trail networks to maximize their collective intelligence. In the third chapter, we follow the trails of four-legged mammals like elephants, sheep, deer, and gazelles, to learn how they manage to navigate immense territories, and how our efforts to hunt, herd, and study them have shaped our development as a species. Chapter four chronicles how ancient human societies stitched together their landscapes with networks of footpaths, which then became tightly interwoven with the vital cultural threads of language, lore, and memory. In the fifth chapter, we unearth the winding origins of the Appalachian Trail, and other modern hiking trails like it, which stretch back centuries to Europeans’ colonization of the Americas. In the sixth and final chapter, we trace the longest hiking trail in the world from Maine to Morocco, and we discuss how trails and technology—having combined to create our modern transportation system and communication network—connect us in previously unimaginable ways.
As a writer and a walker, I am limited by my experience, my background, and my place in history. If this book strikes some readers as too Americentric, or too anthropocentric, I beg their forgiveness; I am, after all, just one American human, doing my best to make sense of a deceptively complex topic. It is also important to note that although the structure of this book is loosely spatial and chronological—moving from the tiny and ancient to the huge and futuristic—this book is not what philosophers call a teleology, a succession of rungs leading up to an ultimate goal. I am not so foolish as to believe that trails have been evolving for hundreds of millions of years only to culminate in the hiking paths of the twenty-first century. I urge readers to avoid interpreting this book’s structure as a ladder leading upward, but to instead regard it as a trail winding from the dim horizon of the past to the wide foreground of our present circumstances. Our history is one of many paths we might have taken, but it was the one we took.
Trails can be found in virtually every part of this vast, strange, mercurial, partly tamed, but still shockingly wild world of ours. Throughout the history of life on Earth, we have created pathways to guide our journeys, transmit messages, refine complexity, and preserve wisdom. At the same time, trails have shaped our bodies, sculpted our landscapes, and transformed our cultures. In the maze of the modern world, the wisdom of trails is as essential as ever, and with the growth of ever-more labyrinthine technological networks, it will only become more so. To deftly navigate this world, we will need to understand how we make trails, and how trails make us.
CHAPTER 1
IT IS IMPOSSIBLE to fully appreciate the value of a trail until you have been forced to walk through the wilderness without one. There is a practical reason why, for more than a thousand years, after the fall of Rome and before the rise of Romanticism, little was more abhorrent to the European mind than the prospect of a “pathless” or “tangled” wilderness. Dante famously described the feeling of finding oneself in a “wild, harsh and impenetrable” forest without a path as “scarcely less bitter than death.”
Five hundred years later, a Romantic like Lord Byron could proclaim that there is “a pleasure in the pathless woods,” but only once the wilds of Western Europe had been tamed and caged. By that point, the true “pathless wilderness” was believed to exist only on other continents, like North America, where the phrase was still being used well into the nineteenth century.I The American wilderness came to symbolize an inhospitable and far-off land, cold, cruel, and uncivilized. At the Boston Railroad Jubilee in 1851, the politician Edward Everett described the land between Boston and Canada as a “horrible wilderness, rivers and lakes unspanned by human art, pathless swamps, dismal forests that it made the flesh creep to enter . . .”
Pathless wildernesses still exist in the modern world, and at least some have retained their power to elicit dread. I have visited one such place. It lay on the northern rim of a glacial fjord called Western Brook Pond, on the island of Newfoundland, in Canada’s easternmost province. If you want to be taught (however harshly) the blessing of a well-marked trail, go there.
To cross the fjord’s stygian waters, I had to hire a ferryboat. Aboard the ferry, the captain explained that the water below the boat was so pure (in a hydrologist’s terms, so ultraoligotrophic) that it bordered on nonexistence; he said it played havoc with the sensors in modern water pumps because the water couldn’t even carry an electrical current.
On the far side of the fjord, the captain dropped me and four other hikers off at the base of a long ravine, where a series of animal trails led through a dense fern jungle and up a granite cliff face bisected by a waterfall. This was my first hiking trip since returning home from the Appalachian Trail. I felt strong; my pack was light. Weaving through the tall ferns, I quickly passed the other hikers. At the top of the ravine I found a vast green tableland. The trail I had been following vanished altogether. Soaked in sweat from the hike up, I took a moment to rest, my feet dangling over the cliff’s edge. At the ragged western edge of the tableland, it abruptly dropped hundreds of feet to the fjord’s indigo water.
I sat and watched as the other hikers wound their way up the ravine. Once they had reached the top, the other four hikers all headed south, along a more scenic route. Watching them go, laboring beneath their heavy packs, I felt a swell of confidence. I rose, map and compass in hand, and headed north. This shouldn’t be too tough, I thought. After all, it’s only sixteen miles.
As I began hiking, however, that confidence soon withered. One might suppose that, after a lifetime of walking within the rigid confines of trails and pathways—from wilderness footpaths to the moving walkways in airports—it would come as a relief to roam free in any direction. But this was not the case. A low bass beat of terror throbbed behind my every decision. I was alone, and without any means of communication save a small, park-issued radio locator beacon, which resembled a large plastic pill with a wire hanging out of it. It could be used, I had been assured, to track me down if the park ranger’s office hadn’t heard from me for more than twenty-four hours after my scheduled return. It seemed a wonderful device for recovering corpse
s.
More bedeviling though, was the sheer number of minuscule choices I was forced to make at each turn. Even with a rough idea of where I was meant to go, there were still countless decisions to make at any one moment: whether to slant uphill or down; whether this tuft of grass or that would support my weight as I tiptoed across a bog; whether to hop along the rocks on a lakeshore’s edge or bash my way through the bush. In every landscape, as in every mathematical proof, there are countless routes one can take to the solution, but some are elegant and others are not.
My navigational woes were compounded tenfold by the problem of what Newfoundlanders call “Tuckamore”—groves of spruce and fir that have been dwarfed by strong winds. From afar, the trees resemble a scrum of fairy-tale hags, all hunches and claws. Like most elfinwood trees, they can grow for centuries without ever reaching any higher than one’s chin. What they lack in height, they gain in hardiness.
Countless times on my hike, I would reach a section where a small grove of Tuckamore stood between me and where I needed to be. I would glance at my watch to mark the time, estimating it should take no more than ten minutes to cross. Then I would take a deep breath and enter the low green copse. It was like dipping into a nightmare. Suddenly the air was dark, and the space apportioned chaotically. As I fought to take each step, branches clawed red gashes into my skin and pulled the water bottles from the pockets of my backpack. Out of frustration, I tried stomping on the trees, to break them, or at least to punish them, but to no avail; they sprang back, unharmed. Here and there a set of moose or caribou prints would form a narrow, muddy game trail, but after a short while it would dwindle or veer astray. Off to the left, a pocket of sunlight would appear, and I would follow it, only to find a pool of mud. It was like moving through a labyrinth that left you no choice but to, from time to time, lower your shoulder and charge your way through the walls.