| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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trail less traveled It's A Vertical Life It’s just after eleven when I awake, in the middle of a sodden and still August night. I’m curled up in one of my favorite places: high off the ground, suspended on a ledge off the side of Yosemite’s Half Dome. Burrowed into too-hot sleeping bags, cradled in a mesh of slings and canvas fabric, my climbing partner, Rick, and I are 2,000 feet above the ground. In daylight, the towering pine trees below have dwindled to shrubbery, and the sense of exposure is keenly gratifying. With luck, we’ll reach the top tomorrow after a short day’s climb. After two days on the rock, the itch to finish is growing stronger. No clouds above—a good sign. With nowhere to take shelter, rain on a vertical wall is at best a nuisance and a soaking, at worst a quick route to hypothermia. I shift and nudge Rick’s feet back onto his half of the ledge, settle in for sleep...and wake with a start to a distinct plop. Rain? The sky is perfectly clear. Plop. I’m sure of it now. “Rick. Rick!” I hiss. “Rain!” Rick bolts upright, the word snapping him alert. We work in a frenzy, constrained by the difficulties of moving quickly on a swaying fabric platform. Headlamps on, we stash spare clothes in waterproof niches, squirrel food into a bag—all to a steady and growing cadence of plops—and finally we set about waterproofing ourselves by squirming into our bivy sacks, waterproof bags that resemble nothing so much as oversized Ziploc baggies. “Sharif.” I look up from my labors to see Rick, motionless, headlamp illuminating a silver dollar-sized circle of light on his sleeping bag. “We’re not getting wet,” he says. “They’re bugs.” I pause. Hold out my hand. Stick out my tongue. Screwing my headlamp down to a narrow cone, I focus on the fabric of my sleeping bag. The surface is crawling with wriggling, glinting insects more antenna than body. It’s raining silverfish. Welcome to the rich domain of one of Yosemite’s least-explored ecologies—its many miles of vertical granite. Though Yosemite is one of the most visited parks in the nation, most visitors’ exposure to the wildlife in the park is limited to its valley floor denizens: California ground squirrels, raucous scrub jays, and the all-too-common marauding black bears. From the Valley floor, the walls that tower above look like unlikely refuges for animal life. Rather, they appear every bit like the “granite deserts” famed Yosemite climber and writer John Long termed them. But hours dangling in slings high above the valley floor have given me glimpses of a surprisingly rich ecosystem. Some of the inhabitants are transient—perhaps including the silverfish, which we never saw again—but many organisms are permanent cliff residents, carving out homes in gravitationally demanding terrain. With dawn, our climb continues. Above me, Rick inches out of view, disappearing inside a narrow chimney of rock. I pay out slack to the climbing rope. The gusting breeze occasionally whistles as swifts howl by, their aerial acrobatics turning them into pint-sized fighter planes. It’s no surprise that the most common animals on the walls are avian: swifts, swallows, and, on rarer occasions, the cliffs’ most famous residents, peregrine falcons. Canyon wrens are at home in the nooks and crevices of the cliff, too. Despite a perpetual air of frantic industry, they will sometimes venture near to investigate climbers inching through their turf. With a grunt, I ratchet my ascenders along the rope Rick has secured to the wall, muscling my way up. While birds are the bona fide residents of this vertical world, many of the walls’ other animals are transients who risk the vertical terrain only for as long as it takes to snatch a meal from an unwary climber. In this regard, the ringtail, Bassariscus astutus—which couldn’t be better named—is without peer. Almost strictly nocturnal, these curious creatures are master pickpockets. From lairs in the rocky talus girdling the cliff bases, they employ stealth and a well-developed climbing ability to glean easy meals from climbers’ stashes. I watched one ascend 40 feet of near-vertical rock with ease—to claim a bag of my bagels—and then descend the same route, nose first, like a squirrel down a tree. What the ringtail possesses in guile and climbing talent, wood rats make up for in persistence and numbers. Along with frogs (which are surprisingly common on the granite walls of Half Dome), these rats are one of the few non-avian full-time residents of the walls, making homes in the recesses of the innumerable cracks and fissures. Like the ringtails, they’re built for nighttime activity, and I’ve rarely spotted more than their saucer-sized eyes, reflected in the glare of my headlamp, crowned by oversized heat-dispersing ears. Despite their reticence, wood rats hold a small place in the annals of Yosemite climbing history. During climber Warren Harding’s historic first ascent of El Capitan’s 3,000 feet, wood rats high on the wall made a meal of his sleeping bag. Harding, chilly but unfazed, pushed on and eventually reached the top after nearly a month of hard climbing. Ascending a fixed rope with mechanical ascenders—climbers call it “jugging”—is grueling work, akin to doing pull-ups and using a StairMaster at the same time. Still, it offers a glimpse of the barren places in which only the most resourceful organisms can eke out a living. I ease off the toil of jugging and rest on my slings to catch my breath and inspect the rock. Lichen are ubiquitous, mottling the gray granite with green and black. Yellow-and -ed stonecrop flowers (Sedum obtusatum) are here too, anchored in cracks the width of a nickel. Scarlet penstemon (Penstemon rostriflorus) are not quite as tenacious, but where the cliff relents, if only for a few horizontal inches, their brilliant crimson petals punctuate the gray granite ledges. In his book Our National Parks, John Muir celebrated the beauty and hardiness of these cliff-dwelling flowers, marveling that "even the majestic canyon cliffs...are cheered with happy flowers on invisible niches and ledges, wherever the slightest grip for a root can be found." There's just 50 feet between us and top now. The smooth, bald face of Half Dome is relenting, gradually relaxing to a horizontal pitch which will, blessedly, allow us to walk upright once more. Another sign that we're nearing the top: a western fence lizard, sunning himself on a ledge. Spotting one of these is akin to sighting a seagull on the high seas: a sure sign that terra firma is close, as these lizards are mainly creatures of horizontal spaces and don't venture too far on vertical cliffs. Their gray-brown color, mottled with black chevrons, would make for fine camouflage against the rock. But the male's curious habit of doing vigorous push-ups, which reveal its blue belly, tends to give it away. It seems an undignified apprach to courting, but then, it's not me he's wooing. It's my turn to lead this section of the climb, so, donning the clanking harness I set off up the rock face, making quick progress on the shallow incline. With a hop and a belly flop onto a bench of rock, at last the summit is ours! Half Dome 's barren moonscape of unadorned rock and rubble frame a vista of the rugged peaks of the High Sierra, the highest capped by snow. As Rick clambers up the summit block, he surprises another inhabitant of this unique terrain: a lone marmot, its head swiveling like a periscope as it surveys these strange intruders. Squat and round, with a Buddha-like serenity, the marmot looks more complacent than his smaller and craftier counterparts back on the wall. He's a welcome confirmation of our return to the land of the horizontal. Sharif Taha is a graduate student in neuroscience at the University of California, San Francisco. |
Spring 2001
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