Picture of mountain with flat top, waterfalls and clouds.
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Untouched by time, this pristine world soars high above the Amazon

A flat-topped peak gives researchers a chance to identify new species and unlock secrets of evolution. The biggest challenge: getting there.

Mount Roraima rises from the rainforest where the borders of Guyana, Brazil, and Venezuela meet. Locals call it and similar flat-topped mountains tepuis (pronounced tuh-POOH-eez), or “sprouting rocks.” They’re the remnants of a primeval plateau that eroded over millions of years.
ByMark Synnott
Photographs and video byRenan Ozturk
March 22, 2022
45 min read

On a pitch-black February night, Bruce Means stood alone, deep in the Pakaraima Mountains in northwestern Guyana. Scanning the cloud forest with his headlamp, he peered through his foggy glasses at a sea of ancient trees cloaked in beards of verdant moss. The humid air, ripe with the smell of decaying plants and wood, trilled with a melodious symphony of frogs, drawing him like a siren song so deep into the jungle that he wondered if he would ever make it back out. 

Grasping a sapling in one hand for balance, Bruce took a shaky step forward. His legs quivered as they sank into the boggy leaf litter, and he cursed his 79-year-old body. At the beginning of this expedition, Bruce had told me that he planned to start slowly but would grow stronger each day as he acclimated to life in the bush. 

After all, during his career as a conservation biologist, he’d made 32 previous expeditions to this region. I’d seen a photo of him in his younger days—a six-foot-four, broad-shouldered backwoodsman, with his long hair pulled into a ponytail and a huge snake draped over his neck.

Picture of aerial view of winding river running through forest.
There are no roads in this part of the country; to trade goods, villagers rely on waterways that lace the jungle. Occasional rainy-season floods disrupt gold and diamond mining downstream but also allow outsiders to use boats to explore remote areas for potential claims.
Photograph by Matthew Irving

He’d told me stories about riding rickety buses in the 1980s across the plains of Venezuela’s Gran Sabana and then setting off into the mountains, where he hunted for new species of amphibians and reptiles. Once, he’d spent days alone on the summit of an obscure peak, sometimes naked, living as close to the natural world as he could. These were all an extension of the explorations he’d made as a kid in Southern California, tramping through the Santa Monica hills looking for alligator lizards and tarantulas, or, as he likes to say, “small experiences of the magnificence of nature.”

It was that philosophy that had led him here, now. Sure, the ponytail was gray and thin, and at 285 pounds, he was well over his fighting weight, but he assured me he still had the fire. Soon, he would find his rhythm.

But the jungle—with its swarming insects, incessant rain, and sucking bogs that threaten to swallow a person whole—has a way of wearing one down, and after a week of rugged bushwhacking and endless river crossings, it was obvious to everyone on our expedition that he was growing weaker each day. At night, a rattly cough kept him awake, and as he lay in his hammock, he thought about home back in Tallahassee, Florida, where his wife and two grown sons had practically begged him not to go on this trip. The wilds of the Guiana Highlands are no place for an out-of-shape septuagenarian. 

(He braved an arduous 700-foot vertical climb to capture this stunning image)

For Hungry Minds

And yet, I’d seen Bruce rally before. We’d made three previous trips to this region, a remote hot spot of biodiversity called the Paikwa River Basin, that lies on the northern edge of the Amazon rainforest. Bruce’s main interest here was frogs, and if the planet held a frog paradise, this was surely it. 

Frogs play a critical role in ecosystems around the world, but nowhere have they existed for longer than in equatorial rainforests like this one. For millions of years, the frogs here have followed an array of evolutionary pathways, resulting in a profusion of species in all shapes, sizes, and colors, and with astonishing adaptations. 

Picture of man with gray hair lying in water and showing round rock in his stretched out hand.
Bruce Means looks under rocks for frogs and other species unknown to science. During the expedition, the 79-year-old biologist explored many watery habitats. Even a pond can be a tiny universe of life, he says, likely to contain species that exist nowhere else.

More than a thousand amphibian species have been described in the Amazon Basin alone—from jewel-like poison dart frogs (named for their primary use among Indigenous people), to glass frogs (with skin so thin it reveals their beating hearts), to milk frogs (which live high in the canopy inside water-filled tree holes), to the recently discovered zombie frogs (that spend most of their lives underground). Many of these have yielded breakthroughs in medicine, including new types of antibiotics and painkillers and potential cancer and Alzheimer’s treatments.

Scientists believe they’ve identified only a fraction of the world’s frog species. Meanwhile, the ones we do know of are disappearing at an alarming rate. By some estimates, up to 200 frog species may have gone extinct since the 1970s, and Bruce and other biologists fear that many others will die out before we even know they exist. What secrets about evolution, medicine, or other mysteries would be lost with them?

Bruce refused to dwell on such gloomy ruminations. He focused instead on the wealth of biological treasures these rainforests still held. “The potential for future discoveries in the Paikwa is virtually limitless,” he told me, his voice filled with his trademark enthusiasm. But he also knew that time was running out—not just for the frogs but for him too.

Picture of group of porters crossing water.
Armed with a machete and walking sticks, Bennett Morris (at right), along with other Indigenous Akawaio guides, leads the team on the 40-mile trek through the dense jungle of the Upper Paikwa River Basin to the base of the tepui known as Mount Weiassipu.

Guyana is something of an oddity as the only English-speaking nation in South America, a legacy of its history as Britain’s only long-term colony on the continent. Most of the country is covered in untracked rainforest, but in the far northwestern corner, the Pakaraima Mountains run along Guyana’s border with Brazil and Venezuela. Here, several table-topped mountains, which resemble the monumental mesas in the deserts of the American Southwest, rise sharply above the dark green canopy of the Paikwa River Basin. To the local Pemon people who’ve lived in their shadows for centuries, these otherworldly peaks are known as tepuis (pronounced tuh-POOH-eez)—or “sprouting rocks”—sometimes called “houses of the gods.” 

Unlike typical mountain ranges that often form in linked chains, tepuis tend to stand alone, emerging from the rainforest like islands poking out of a foggy ocean. A few of their summits can be reached by hiking routes, but most are ringed with sheer cliffs—some up to 3,000 feet tall—and often are festooned with spectacular waterfalls. 

Geologists tell us that tepuis are the remnants of an ancient plateau, called the Guiana Shield, that once formed the heart of the supercontinent known as Gondwana. Hundreds of millions of years ago, when this part of South America was connected to Africa, the Guiana Shield stretched across parts of what is modern-day Guyana, French Guiana, Colombia, Brazil, Venezuela, and Suriname. This mass of ancient sandstone and quartzite gradually fractured and eroded until roughly 30 million years ago, when the hundred or so tepuis that exist today took on something resembling their present form.

Gondwana split apart eons ago, but this part of South America still holds many clues to its shared past with Africa. Today some of the species endemic to tepuis are closely related to plants and animals found in West Africa, and the types of diamonds mined in Sierra Leone and Guinea are the same as those that erode from tepui cliffs and are carried downstream in the Paikwa and other rivers. 

‘Tepuis are like the Galápagos Islands,’ Bruce once told me, ‘but so much older and more difficult to study.’

The first European to see a tepui was probably the English explorer Sir Walter Raleigh, who led an expedition up the Orinoco in 1595 while searching for El Dorado, the fabled lost city of gold. Raleigh wrote about seeing a crystal mountain in the distance, which might have been Mount Roraima: “It appeared like a white church-tower of an exceeding height. There falleth over it a mighty river which toucheth no part of the side of the mountain, but rusheth over the top of it, and falleth to the ground with so terrible a noise and clamour, as if a thousand great bells were knocked one against another.” 

I first learned of these otherworldly rock formations as a boy, when I read Sir Arthur Conan Doyle’s 1912 classic, The Lost World. In this science-fiction tale, a scientist discovers dinosaurs and protohumans living on an isolated plateau hidden deep in the Amazon jungle. That book and its protagonist, the ebullient Professor Challenger, jumped to mind when I first met Bruce in 2001 through mutual friends at the National Geographic Society. He recounted some of his explorations of tepuis, describing them as individual laboratories for evolution—islands in the sky—that have been completely isolated for so long that some frog species exist on the summit of a single tepui and nowhere else on Earth.

Picture of man resting in hammock.
Akawaio team member Franklin George rests after a day of hacking through the jungle and hauling supplies, often under a steady rain. During the trek to Weiassipu, the team set up shelter each evening and wrung out their clothes. “The jungle just swallows you down day after day,” says writer Mark Synnott. “We were constantly soaked and slathered in mud. We called it living in mud world.”

“Tepuis are like the Galápagos Islands,” he once told me, “but so much older and more difficult to study.” 

He had been looking for someone to help him access the most inaccessible terrain on and around the tepuis. With my background as a professional climber, I could do just that. So in 2003 and 2006, we spent weeks searching for new frog species in the jungle below Roraima. While flying home in a helicopter after the second trip, we passed over a small tepui that wasn’t on our map. Its summit was incised by a 600-foot-deep sinkhole with a thick forest at its bottom. Bruce grabbed me by the shirt and shouted in my face, over the sound of the rotors, “Mark, I need to be in that hole!” 

Six years later, in 2012, a helicopter dropped Bruce and me on top of that tepui, called Mount Weiassipu (pronounced why-OSS-i-pooh), and I helped him rappel into the sinkhole. After five days of camping at the bottom and crawling around at night through what Bruce described as “a lost world within a lost world,” he found a tiny frog he described as a “missing link” in tepui evolutionary biology. A single specimen of this species, named Oreophrynella weiassipuensis, had been collected by a team of spelunkers in 2000, but it hadn’t been properly preserved, and as a result, very little was known about it or its relationship to others in the genus known as pebble toads. 

Picture of two people looking at cascading water fall.
Synnott and Honnold stand below a cascade called Double Drop Falls, where they established a base camp. From there, the team cut a five-mile trail through pristine rainforest to the base of Weiassipu. Then they climbed the tepui, searching for frogs and other species.
Photograph by MATTHEW IRVING

The “Oreo,” as Bruce called it, was chocolate brown, about the size of his thumbnail, with four-toed feet that reminded me of Mickey Mouse’s cartoon hands—an evolutionary adaptation that enables these frogs to climb like no other. It was the seventh known species from the Oreophrynella genus. Each of these species lives separately from the others; six are found only on their own tepui summits and one in the cloud forests of the Paikwa River Basin. 

They’ve each followed distinct evolutionary paths, but at least two share a remarkable adaptation that allows them to escape predators. When a tarantula or scorpion attacks, these frogs curl into tight, pebble-size balls and roll and bounce down tree branches, vines, leaves, or rocky surfaces until they’re out of harm’s way. By the end of that trip with Bruce, I wasn’t sure who was more charming, these minuscule frogs or the man who had dedicated his life to studying them. 

There was another frog on top of Weiassipu that Bruce had photographed and captured but wanted to study more. This one had classic tree-frog hind feet designed for climbing. Based on its size, brown color, and white-speckled belly, Bruce was confident that it was a new species of the genus Stefania. 

For years, he and his collaborator, Belgian biologist Philippe Kok, had been building Stefania’s evolutionary tree. By charting the DNA from other Stefania frogs, they concluded there were missing species. If Bruce could collect this elusive frog on top of Weiassipu and prove through DNA analysis that its ancestors evolved for millions of years to suit that ecosystem, cut off from the rest of the world, he’d be a step closer to a more complete understanding of how life evolves on tepuis.

So Bruce had proposed one final expedition to the Guiana Highlands to find this Stefania and to sample the species richness of other amphibians and reptiles in the Paikwa River Basin. We’d travel by bush plane and dugout canoe along the Kukui and Ataro Rivers, then trek 40 miles through untracked jungle to Weiassipu, which we would attempt to climb via its sheer north face. “This is probably the last one I’ve got in me,” Bruce said. “But I’ll get there. Even if I have to crawl.” 

My challenge was to devise a way to help Bruce look for new species in the one tepui environment that no scientist had ever studied: the cliff faces. But safely hauling a man who would turn 80 on this expedition up a big-wall rock climb would take skills well beyond my own. So I recruited two ringers: climbing superstar Alex Honnold, 35, whose ropeless ascent of El Capitan in Yosemite National Park was documented in the film Free Solo, and Federico “Fuco” Pisani, 46, a Venezuelan-Italian and one of the world’s most experienced tepui climbers. 

Bruce summoned his reserves and pushed on through the jungle in search of frogs. 

For days we’d been trudging across a swampy floodplain through ankle-deep mud that almost sucked our boots right off our feet. It rained incessantly, and even when the sun poked through the low clouds, it never penetrated the dense canopy overhead. Down in the steamy understory, mosquitoes and biting flies reigned, and our sweat-soaked clothes, slick with mud and ripped by thorns, stuck to our rashy skin. Every day we crossed countless tea-colored rivers and creeks via precarious log bridges. The slow-moving water, which was also our drinking source, was stained from decaying vegetation—something that no amount of purifying could remove.

Even Alex found the conditions challenging. But for Bruce, the trek had devolved into a harrowing ordeal. He fell often and hard. Lacking the balance and confidence to cross the many log bridges, he opted instead to slide down the steep embankments and wade or swim across the water. Once, he’d somersaulted down a steep riverbank, landing facedown in a creek. After it was clear he wasn’t hurt, someone broke the tension with a joke about the jungle being guilty of “elder abuse.”

Everyone laughed—including Bruce. But as he continued to struggle over the next several days and as the trail grew more treacherous, the humor died off. Bruce’s safety became an ever present worry for our team.

Picture of two persons on vertical cliff face.
Federico “Fuco” Pisani, one of the world’s most experienced tepui mountaineers, leads climber Alex Honnold up a section of Weiassipu. They hoped to find new frog species on the rugged cliff faces, the one tepui environment scientists have never studied.
Photograph by MATTHEW IRVING

After a week of this, we finally set up a base camp of sorts downstream from a roaring 200-foot cascade that Bruce called Double Drop Falls. It looked like a gargantuan two-hump waterslide and hammered into a pool with such force it filled the air with a fine mist that drifted over the camp. 

The team gathered under a tarp, sitting on a bench around a crude table made from fallen logs, to take stock of our situation. Bruce spread a map across the table, and with a wrinkled finger, he traced the route that still lay between us and Weiassipu. To the south lay a valley that was unexplored, according to our team’s Akawaio guides, members of the small Indigenous group that lives in the area where Guyana, Venezuela, and Brazil converge around Roraima. Above the roaring falls rose the massive tepui, Weiassipu, which remained hidden behind thick forest canopy and swirling clouds. 

Sitting across from me at the table, Alex was practically vibrating, so eager was he to get to the mountain where he could climb his way up and out of what he called “mud world.” Fuco, bespectacled and with thick curly brown hair flecked with gray, sat quietly next to me. He’d led more than 20 expeditions to the tepuis over the past 27 years, but he’d never been involved in a scientific expedition on a tepui. He’d always wanted to be a scientist, even pursuing a Ph.D. in biology at one point, and I noticed that Bruce often called on Fuco when trying to identify the flora and fauna that surrounded us. 

Picture of person working through dense vegetation.
On top of Weiassipu, Pisani searches for frogs among a thicket of tank bromeliads. Each tepui offers a unique opportunity to study evolution, because many plants and animals on its summit have been isolated from other species for thousands of years.

Standing behind Alex were the leaders of the 70-strong team of local Akawaio people who were supporting our expedition as guides and porters. Edward Jameson and Troy Henry were legendary among the Akawaio for having climbed the 1,500-foot Prow route of Roraima with a British expedition in 2019. They didn’t know it yet, but we had brought medals from Guyana’s newly elected president, Mohamed Irfaan Ali, to present to them in honor of their feat.

Short, rippling with muscle, and constantly smiling, Edward, 55, had accompanied Bruce and me on our previous expeditions to the region. He’d grown up in this forest and could survive out here more or less indefinitely with little more than his trusty machete, which he kept razor sharp with a file he wore on a string around his neck. He told me that since our last expedition, he’d been working off and on as a mining prospector, or “pork-knocker,” a Guyanese term that refers to the miners’ backcountry practice of living on pickled wild bush hog. 

Since I’d last seen Edward in 2006, Guyana had been gripped by a gold rush. A few thousand artisanal mines had been dug throughout the country’s interior. Like most Akawaio, Edward had spent much of his life farming and hunting. But the lure of earning cash, maybe even finding life-changing treasure deep in the jungle, was impossible to resist. He described how the miners would dig down to a layer of clay, then inject high-powered jets of water to blast the clay into a slurry, which then was pumped to the surface, sluiced and rinsed, and then mixed with mercury, which binds to the gold. The chemical process especially worried Bruce.

“A teaspoonful of mercury can contaminate an entire river system,” he told me. 

Picture of toad.
MacConnell’s pebble toad (Oreophrynella macconnelli) inhabits the forest near Double Drop Falls and is one of two known species of pebble toad that don’t live on a tepui summit.
Photograph by RYAN VALASEK
Picture of frog with red eyes.
An unnamed species of Stefania was found in the cloud forest below Weiassipu.
Photograph by Renan Ozturk
Picture of tree frog.
The Roraima tree frog (Boana roraima) lives between the leaves of arboreal bromeliads.
Photograph by RYAN VALASEK
Picture of frog with large black eyes.
The Kanaima tree frog (Nesorohyla kanaima) has unusually dark eyes. “Few other frogs have irises so black that you cannot see their pupils,” Bruce Means says. It’s unclear what advantage black irises may have over colorful ones.
Photograph by Renan Ozturk

An Akawaio named Denver Henry showed me a map detailing the location of dozens of mining claims scattered across the rainforest surrounding the Paikwa River. So far, the pork-knockers had been held off by the inaccessibility of the terrain and the Akawaio’s resistance to building an airstrip in their villages. But Edward told me that during the last rainy season, when the lowlands flooded, outside prospectors had come in with boats from Kamarang, one of the biggest villages in the region, to explore claims. Every year these mines get a little closer to the Paikwa River Basin. 

Around the table, we agreed Bruce needed time to recover, so we decided to split up. The climbing team would move ahead to cut a trail to the base of Weiassipu’s north face, about five miles away, while Bruce and a team of Akawaio collected specimens at Double Drop Falls. 

Bruce emerged from his hammock the next morning wearing only muddy briefs and was met by a group of Akawaio holding gallon-size Ziploc bags. At the beginning of the trip, he’d announced that in order to sample the biodiversity, he would pay for specimens. The payout was 100 Guyanese dollars (about 50 cents) per creature, with a premium bonus for a Stefania frog, which immediately created a thriving microeconomy in a land where there is little opportunity for Indigenous people to earn hard currency. 

Bruce opened his journal to a blank page and started taking notes. Edward was first in line. His baggie held four frogs. Salio Chiwakeng was next, with five lizards and six frogs. Markenson James confidently delivered a large black scorpion, Tityus obscurus, and his friend presented a spider fit for a Stephen King movie. Bruce pulled it out of the bag with his bare hand, pinching its hairy body between his fingers as one might hold a crab. “Theraphosa blondi,” he said, “aka the Goliath birdeater.” A member of the tarantula family that happens to be the world’s largest spider by mass (and yes, it eats birds), this one tipped the scales at half a pound and was six inches across. It stared at us with beady eyes and bared curved black fangs that looked like a vampire’s. After jotting down a few notes, Bruce put it onto his balding pate and let it walk around.

Picture of mountain with flat top and clouds over forest below.
The nine-mile-long east face of Roraima, Guyana’s highest point, towers above the Paikwa River Basin. Frequent rain on its summit drains into the watersheds of three of South America’s major rivers: the Essequibo, Amazon, and Orinoco.

Meanwhile, Alex, Fuco, and I loaded up with food and gear for the climb, including a thousand feet of rope and three hanging cots, called portaledges, for camping on the side of the cliff. Two Akawaio guides, Harris Aaron and Franklin George, led us up a narrow ridge and over a hump into a thick forest. Wielding machetes, they slashed a path through a carpet of giant ferns and between old-growth trees held fast in the thin, sandy soil with colossal buttress roots that extended, pyramid-like, 20 feet across their bases. 

Spiky bromeliads of every conceivable size and color covered the ground and grew up the sides of the trees, sprouting from clumps of moss. Orchids with delicate white flowers emerged from rotten stumps. White bellbirds, rainbow-colored macaws, and tiny iridescent hummingbirds darted through the leaves, filling the air with their warbles and whistles. For brief moments the clouds would lift, letting the sun filter through holes in the canopy, illuminating patches of the steamy forest floor where luminous blue morpho butterflies flitted in shafts of light.

On the second day of fighting our way to the base of Weiassipu, we began to catch glimpses of its towering north face through occasional openings in the forest. Soon we entered a maze of jumbled, slippery boulders cloaked in a spongy blanket of electric-green moss. Gradually, the firm ground gave way to an elevated lattice of deadfall that occasionally would break out from under our feet like a trapdoor. 

This was the Diamond Waterfall, where legend has it the plunge pool at its base sparkles with diamonds the size of one’s fist.

Late in the day I heard a loud oof behind me. I looked back to see Alex hanging by his armpits. One of his legs had broken through the rotten trellis of dead wood and augered into a jagged void between two rocks. After extricating himself, he pulled up his pant leg. His shin was covered in a paste of blood and muck. Fuco caught my eye. He didn’t say anything, but I knew what he was thinking: How in the world are we going to get Bruce through this section? 

When we finally walked out of the forest at the base of Weiassipu just before sunset, it felt like being reborn. The clouds had lifted, and the wall glowed in the dusk. Across the valley, we stared at the nine-mile-long east face of Roraima, where a dozen waterfalls, each as tall as the Empire State Building, poured out of the mountain like flowing ribbons of golden silk.

Franklin directed our attention to the most spectacular cataract, which burst from a hole in the side of the cliff about 200 feet below the rim. This, he said, was the Diamond Waterfall, where legend has it the plunge pool at its base sparkles with diamonds the size of one’s fist. It’s a tale that dates back to Sir Walter Raleigh, who wrote that some of his Native guides promised to bring him to a mountain that had “very large pieces growing diamond-wise; whether it be crystal of the mountain, Bristol diamond, or sapphire, I do not yet know, but I hope the best.” 

Early the next morning, we started to climb Weiassipu. Our plan was to ascend the wall via whatever seemed to be the best route, laying a trail of ropes anchored to the mountain along the way. When the entire cliff was rigged, we’d strap Bruce into one of the portaledges and haul him up behind us. From the comfort of this hanging platform, Bruce would look for new species on the vertical walls that guard Weiassipu’s summit. 

Progress was painstakingly slow, and by late afternoon, Fuco and I found ourselves huddling on a small ledge about 150 feet up the wall. Above us, a mud-stained rope snaked up and across a 25-foot horizontal section of rock—known in climber parlance as a roof—to where it was tied to Alex, who hung like a bat with his left leg hooked over a spike of rock. 

“What do you think?” he called down. “Should I go for it?” The last section of the roof followed a flake of rock that stuck out from the wall like a diving board. There was no way to say for sure how solid it was. Earlier that day I had taken the first whack at this pitch, getting to where Alex was now, before chickening out and handing over the lead to Mr. Free Solo. 

“Better to leave it for tomorrow,” yelled Fuco. “It will be dark in a few minutes.” 

Without saying anything else, Alex reached out to the edge of the flake with his right hand, cut his feet loose, and swung out over the void. Then he proceeded to go hand over hand across the flake, completely trusting that it would stay attached to the mountain. After 15 feet or so, he let go with one hand to chalk up his fingers.

Picture of man with gray pony-tail reaching tree trunk with his hand. Waterfall on background.
Means pauses for a moment by Double Drop Falls before leaving the rainforest he’s studied for 35 years. The 2021 expedition was his 33rd and final scientific mission to the Upper Paikwa, yet much remains to be discovered. Only about half of the region’s frog species have been scientifically identified, Means says. “It’s up to someone else to pick up where I’ve left off.”

Watching him dangle casually by one arm, 200 feet above the jungle, I was struck by the uncanny resemblance he bore to a pebble toad I’d seen clinging to Bruce’s finger a few days prior. Seconds later, Alex reached for another crack above his head, and the last thing I saw as darkness enveloped the mountain was his legs slithering over the lip. 

That night, back down in our makeshift hammock camp at the base of the wall, Alex, Fuco, and I were arguing about the feasibility of our plan. In setting the route, it had become clear to me that hauling Bruce up the cliff like a piece of baggage was going to be a lot more dangerous than any of us had expected. My biggest concern was that Bruce was on blood thinners for a heart condition—something he had failed to disclose until we were well into the trek. What if he got hurt somehow and we couldn’t stop the bleeding? 

Right then, a light flashed in an opening in the jungle far below, a signal from base camp. I turned on our radio and heard Bruce’s voice. With a heaviness in his speech, he told us that Brian Irwin, our expedition doctor, had just persuaded him to pull the plug on our harebrained plan. 

“I can’t tell you how much this grieves me,” Bruce said. “Fuco, especially, knows the herpetofauna well. I’ll send up the picture that I’ve drawn of the Stefania that I’m pretty sure is new to science up there.”

“OK, Bruce,” Fuco said. “I’m going to do my best to find the lucky Stefania.”

(In the heart of a South American rainforest, a team of rock climbers and biologists are the first to climb Mount Weiassipu in search of new species of frogs—and adventure. Listen now on Apple Podcasts.)

The next morning, the entire valley below Weiassipu was enveloped in the same gray mist that we had been living in for days. I now understood why Bruce called this zone a cloud forest. This basin seemed to create its own weather, and it was a rare moment when we could see more than a hundred feet in any direction. It rained for hours, but luckily the wall was overhung just enough that we usually avoided getting wet. 

While Alex led the way, Fuco and I followed, looking for frogs inside cracks and digging into any patches of soil we found. At the end of each pitch, we used pulleys to haul up heavy bags that held everything we needed to survive on the wall for a few days. It was an exhausting day, during which the only creatures we found were a centipede with an orange stripe on its back and a big, possibly carnivorous, cricket. It wasn’t until well after sunset that we crawled into our portaledges, anchored to the wall next to a narrow ledge 700 feet above the jungle. We fell asleep to the sound of rain pattering against our nylon rainflies. 

When the sun rose the next morning, I unzipped the door. The clouds were gone, and the sun pulsed in a deep blue sky. Below, an ocean of clouds blanketed the valley. To the west, I could see dozens of waterfalls pouring from Roraima’s 1,500-foot-tall east face, forming halos of rainbows around the plunge pools at the base.

After downing a cup of coffee and some energy bars, we set off across the ledge, hoping it might lead to the summit. After half a mile of tunneling upward through thick bushes covered in spiderwebs, we turned a corner and found ourselves at the top of the tepui, staring across the plateau. In the span of a few feet, we stepped from a hanging cloud forest onto a bog covered in pitcher plants, yucca, and sundews, glistening carnivorous flora that resembled Venus flytraps. Off in the distance, twin rock pinnacles rose above the sinkhole that Bruce and I had explored in 2012. 

It started to rain, and the clouds that had blanketed the valley began curling over the summit rim and enveloping us. Fuco and I found shelter under a mushroom-shaped rock, where we huddled, soaked and shivering, with my poncho draped over us like a tarp. Alex, meanwhile, had disappeared, presumably to go climb something. 

Fuco called Bruce on the radio. “Where is the best place to find that lucky Stefania?” he asked. I felt bad for Fuco because I knew that he carried the weight of everyone’s expectations. Bruce told him to look on the branches of small trees and shrubbery. But he also mentioned that Stefania like to hide inside clumps of moss during the day and that he usually finds them at night when their eyes catch the beam of his headlamp. 

Fuco and I spent the afternoon wandering in the fog and rain, poking through thick moss and combing branches and leaves, hoping to spot one of the minute frogs, or any kind of vertebrate, but all we found were some tadpoles from a known species of frog. Fuco went out again that night in yet another rainstorm but found nothing. It felt like a major defeat. Although the expedition had been designed to sample a broad range of fauna, the focus had been to find frogs on this tepui, especially the new species of Stefania. That this was probably Bruce’s last expedition made our failure especially crushing.

Two days later we’d run out of supplies and were forced to head down the mountain. Bruce had relocated to a new spot, “Sloth Camp,” a day’s hike above Double Drop Falls. We found him sitting at a workbench sketching a rubbery brown frog, its body laid out on a metal tray next to his notebook. His field lab was covered with several glass jars of formaldehyde, filled with frogs, lizards, and snakes. He lit up when he saw us, but his eyes were puffy and red rimmed. His safari shirt was ripped and splotched with mud. As he gripped the edge of the table and tried to stand, he grimaced, and I realized that he was in a great deal of pain.

“I’m so sorry we didn’t find the Stefania,” Fuco said, handing Bruce a baggie that contained the centipede and cricket. 

“It’s OK,” said Bruce. “The fact that you didn’t find any frogs up there is actually a scientific result in its own right.” I could see that a devilish grin was spreading across his face. He led us over to the workbench, where he picked up the brown frog and held it up for us to see. A small white tag with some numbers was attached to its foot.

“Is that … ?” I said, recognizing it from the sketch of the Stefania that Bruce had sent us.

“I won’t know for sure until I’ve been able to do the DNA analysis,” Bruce said, “but I’m about 95 percent sure that this is a new species of Stefania.” He explained that it was different from the one he’d seen all those years ago on top of Weiassipu—the one Fuco, Alex, and I had just been killing ourselves to find—but it was almost definitely another missing link in the Stefania evolutionary tree that he and Philippe Kok had been working on for years. 

Bruce put the frog back down and started pulling out other specimens to show us. “It’s funny how it worked out,” he said. “Me not going up the wall turned out to be a blessing in disguise, because it gave me time to thoroughly explore this cloud forest, which no scientists have ever investigated before.” 

In all, Bruce was confident he’d found six species new to science, including a nonvenomous colubrid snake and a spectacled lizard, which had a transparent lower eyelid that allowed it to see when its eyes were closed. 

That evening, over a dinner of watery noodles, we discussed what had long been the elephant in the room. Bruce’s condition had deteriorated to the point that there was simply no way he could make the trek out. The only option was to call in an emergency helicopter rescue. 

The canopy was so thick that our satellite phone didn’t work, but after several hours we finally managed to text our coordinates to our outfitter back in Guyana’s capital, Georgetown.

The next day a helicopter descended into the small opening at the base of Double Drop Falls. After a round of hugs, Bruce headed for the chopper, only to trip and fall one last time. As the helicopter climbed out over the jungle, I saw Bruce in the passenger seat looking out the window. I knew he could see Weiassipu and Roraima to the south and west, rising from the cloud forest, their waterfalls casting rainbows and diamonds into the rivers far below. Ahead, the veiny path of the sparkling Paikwa River twisted northward, growing turbid as it passed through the scars of the encroaching mines, which every year draw a little bit closer to this Shangri-la of biodiversity.

As I turned to begin packing up for the long trek back out of the jungle, Edward pulled me aside. From an inside pocket he produced a small plastic vial holding a pea-size raw diamond. Now that our expedition was over, he was hoping I might buy it from him. Holding that tiny stone between my fingers, I thought about all the pork-knockers who wanted to dig mines to pull these out of the ground and all the money they could provide to their families. I marveled at how such a small rock could threaten something as ancient and primordial as the Paikwa River Basin and the tepuis that surround it. And I thought about how my old friend would probably never see this place again—and about the new species that he now carried in the waterproof bag between his feet. 

If the tepui gods were smiling, maybe one of these creatures might prove so rare and singular that the world would finally realize what Bruce Means has known all along: The real treasures of El Dorado aren’t gold and diamonds—they’re the plants and animals that call this magical place home.

Writer Mark Synnott and photographer Renan Ozturk last teamed up to search for George Mallory’s lost camera on Mount Everest. Their story appeared in the July 2020 issue.

The National Geographic Society, committed to illuminating and protecting the wonder of our world, has funded Explorers Bruce Means and Mark Synnott’s expeditions in South America. Learn more about the Society’s support of Explorers.

EXPLORER: THE LAST TEPUI
Follow as the team searches for new species on South America’s sky islands, available to stream on Disney+ starting April 22.

This story appears in the April 2022 issue of National Geographic magazine.

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