Wade Davis will drink blood and eat insects or even a grizzly when he must, but he prefers polar bear, which he says tastes like "the best pork ever." He grows animated when describing mysterious potions made from exotic plants by forest dwellers, especially if they contain some powerful mind-altering alkaloid. Davis counts shamans and voodoo sorcerers among his friends and is equally at home in the foothills of Mount Everest and along the banks of the Río Pira Paraná in the northwest Amazon. Since he abandoned a promising academic career in the 1980s – after his dissertation research on Haitian zombies produced a bestseller and a major motion picture – Davis has traveled the world as an independent anthropologist, ethnobotanist, and "explorer in residence" for the National Geographic Society, campaigning on behalf of vanishing peoples, languages, and habitats.

Davis and I met in the Trophy Room of the Explorers Club in Manhattan, where he was scheduled to deliver a lecture that evening on his latest book, 'Into the Silence: The Great War, Mallory, and the Conquest of Everest.' Within minutes he was describing the effects of ebena, "the semen of the sun," a hallucinogenic snuff used by the Yanomami and other peoples along Venezuela's upper Orinoco. "Jerry Garcia used to say that I was the only guy in America who was allowed to take drugs legally," Davis said proudly, adding that ebena was probably the weirdest hallucinogen he'd ever experienced. The active ingredient is a tryptamine compound, and taking the snuff results in the complete dissolution of reality. "You're not even there anymore."

Our setting was especially appropriate, surrounded as we were by relics of threatened species and dwindling cultures. We were inspecting the room's many trophies, and Davis, wearing a black turtleneck and dark jeans, was nose to nose with a stuffed cheetah, peering into its glass eyes. His longish, wavy blond hair perfectly matched the pelt of the big cat.

Along the dark-wood-paneled walls and even in the rafters of the vaulted ceiling above us were the preserved heads of caribou, bison, Cape buffalo, bighorn sheep, pronghorn antelope. Large lead-glass windows admitted the midday sun, which slanted brilliantly across a lion skin. Glass cases displayed Maori wood carvings, shells from Papua New Guinea, a piece of mauve goat hide labeled as a yeti scalp.

Davis threw himself down on a red leather couch below a large portrait in oil of Peter Freuchen, the great Danish explorer, who inspired a tale that began like this: "When I was narwhal hunting at the tip of Baffin Island, these guys told me this incredible story." It was during the dark days of the 1950s, when the Canadian government was asserting its sovereignty, forcing the Inuit into settlements. "The grandfather of this old man I was hunting with refused to go," Davis said, "so his family took away all his weapons and tools, thinking that would force him into the settlement." Instead, Davis continued, one night the old man "slipped outside the igloo, pulled down his caribou-hide and sealskin trousers, and defecated into his hand." As the feces began to freeze, he shaped it into the form of a tool – a shit knife. "When the implement he had forged in the cold from human waste was fully formed," Davis said, speaking in well-formed prose, "he put a spray of saliva along the edge and used it to kill a dog." The rib cage of the dog became an improvised sled, with strips of the frozen dog skin acting as runners. The old man then tucked his shit knife under his belt and disappeared into the arctic night. An amazing story, no doubt, but Davis remained somewhat skeptical about the existence of shit knives: "I thought they were pulling my leg, obviously." Then, some time later, he read Freuchen's journals, in which the Danish explorer describes being trapped in the barrens under his sled, which he had pulled over him as a shelter but now was a coffin of his own making. "And in his journals, he says totally casually and in passing: 'I thought of making a shit knife, but I really couldn't maneuver.'

It's not like there was an assembly line making shit knives," Davis continued, clearly warming to the subject, "but when you're in the arctic, everything is made from the cold. The runners on the sleds used to be made of fish. There's no wood, so it's three arctic char wrapped in the skin of a caribou hide." Had he ever made a shit knife? "I've never made a shit knife, but if you leave a towel in that cold overnight, it becomes a tool. I have helped dig igloos with shovels made of frozen towels. You know, once something freezes, it's solid. That's the key to the arctic – they didn't fear the cold, they made use of it."

Davis' observation about fear is characteristic of his stories. Similar points abound in his books, and the general theme is consistent. Native peoples tend to work with their environments rather than struggle against them. The contrast he draws is not a matter of magical thinking versus science. The peoples of the Amazon display a sophisticated knowledge about their plants and general environment that is far more precise and empirical than that of the average American or European, many of whom have no idea what's growing in their backyard.

Davis was born in Vancouver in 1953 but raised in Montreal. It was, he says, "a completely suburban Canadian environment." But in the late Sixties and early Seventies, when Davis came of age, Canadian young people had relatively easy access to the bush, and he and his friends all wanted to go north. Beginning when he was 15 years old, Davis spent eight seasons working for the Canadian parks service. "It was sort of a combination Outward Bound and Youth Conservation Corps – teams would go into the remote parks, cut trails, fight fires, build basic stuff like outhouses and cabins, but then also there was a strong component of wilderness training." It was a good apprenticeship for an explorer. "At 16, they'd say to you, there's a forest fire 20 miles up that valley. Go put it out, and if you have time to build a helipad, we might be able to give you a ride out. Otherwise, you'll have to sleep in the bush and walk out tomorrow."

When he arrived at Harvard in 1971, Davis was bewildered to hear people refer to backpacking as a form of recreation. "I had no idea what they were talking about. I had never known about the notion of just going backpacking for the fun of it. We had chainsaws on our backpacks." Those months in the remote Canadian wilderness led to an interest in indigenous peoples and a decision, after two and a half years of college, to head off to South America for 15 months. Of course, he was also inspired by his mentor, the great ethnobotanist Richard Evans Schultes, who helped launch the psychedelic revolution with his discovery of the Aztecs' magic mushrooms and his work on the ritual use of peyote in the American Southwest. In keeping with the spirit of his teacher, and the age, Davis' fieldwork was all about pushing the boundaries of experience and consciousness.

Davis is a formidable talker, and his stories flow in quick succession, ranging from his pathbreaking mid-1980s work on Haitian zombies to his investigation of the belief among a number of anthropologists that a large species of toad, Bufo marinus, was used by the Mayans and other ancient peoples of Mesoamerica as a hallucinogenic drug. Adventurous dope fiends had also heard about the toad theory, it seems, so there was a public health imperative as well. "We were trying to get kids to stop licking toads," Davis said, as he casually tossed a large globe into the air. "Because they were dying." Along with his friend Dr. Andrew Weil, Davis eventually determined that a different species of toad, Bufo alvarius, was the more likely candidate for the ancient toad cult. Through Weil, Davis met a psychedelic wayfarer named White Dog, who had smoked magic toad maybe a hundred times. Toad, according to White Dog, was an "astral propellant," the ultimate spiritual high. After careful self-experimentation, Davis concluded that White Dog spoke the truth: Smoking Bufo alvarius toad venom, which contains some of the same compounds found in the Yanomami snuff, produces a sensual, pleasant, and hallucinogenic effect. "Andy and I were the ones who discovered the first hallucinogen ever from the animal kingdom," Davis said. "We were so proud of ourselves – we thought we'd get Nature or Science magazine. Instead, we were on the cover of the Wall Street Journal. We practically got arrested."The affair of the smoking toad wasn't the first time that Davis' work had stimulated controversy. His research in Haiti also generated some unwelcome attention – mostly, it seems, from conventional academics offended by all the publicity. At Harvard, there was even an unsuccessful attempt to spike his doctoral dissertation. Faculty squabbling and interdisciplinary warfare are hardly unusual, though few dissertations lead to a film directed by Wes Craven. The experience helped Davis realize that he was not meant to inhabit the groves of academe. Despite his long scientific CV – he has published some 150 papers – Davis likes to say that he is essentially a storyteller, and he draws on traditions that are far more ancient than modern science.

Exploration, for Davis, is more than a geographical or narrowly scientific pursuit; in harsh and unforgiving places, under extreme conditions, trials of the body give way to triumphs of spirit that are not easily captured by typical adventure tales or staid scientific treatises. And there are few environments on Earth more extreme than the upper reaches of Mount Everest. In October 2011, after 12 years of labor, Davis published what might appear to be a significant departure: a historical narrative about 26 white men in which he personally plays no role. In fact, Into the Silence represents his most ambitious inquiry to date. It is an exhaustively researched and subtly executed account of the first three attempts to climb Mount Everest – in 1921, 1922, and 1924 – the last of which ended in enigma, near the summit, with the deaths of mountaineers Sandy Irvine and George Mallory.

As we moved downstairs from the Trophy Room, passing dozens of photographs of the great figures who have been members of the Explorers Club, Davis explained how he came to the subject of Mount Everest. While attempting to photograph clouded leopards at the base of the Kangshung Face, his attention was captured by those famous deaths in June 1924 near the summit. He was traveling with Daniel Taylor, the founder of a community-development and educational foundation called Future Generations who grew up in the Himalayas and knew some of the members of the early Everest expeditions. Taylor told stories of Englishmen in tweeds and puttees reading Shakespeare to one another at 23,000 feet. Davis wanted to know who these men were and what energies had motivated them to penetrate the death zone. He had a strong hunch that their experience of the Great War would be important – of 26 men who took part in the expeditions, all but six had fought in the trenches.

The point was not that the Everest mountaineers reminisced about the war while sitting around at base camp. On the contrary, many never spoke of it at all. There was no need. For such men, death was not an undiscovered country, and the extreme conditions they were destined to experience on the North Col of Everest presented no deterrent. "Because death had nothing to teach them," Davis said, "they were prepared to accept a level of risk that would have been unimaginable before the war." Trench warfare, the needless deaths of millions of boys, had shattered the pretensions of empire. All certainties had crumbled, and the world had been drained of meaning. Once the war finally ended, a quest that had been interrupted by Armageddon was taken up again, and a small group of former soldiers threw themselves at the highest mountain on Earth. What had begun as a grand imperial gesture, motivated by the failure of the greatest empire on Earth to win the race to the North and South poles, was transformed by the Great War into "a mission of regeneration."Davis mentioned Daniel Taylor more than once, so I was curious to know what Taylor thought of the book he had helped inspire. Although he is now a professor at the Future Generations graduate school in West Virginia, Taylor's family has lived in the Himalayas for almost a century, and he has helped found nine national parks in the region. When I spoke to him on the phone, Taylor pronounced the book "brilliant" and a "tour de force." Davis, he said, "realized that the really amazing story is not whether Mallory made it to the top but what made the men [go there]." He also pointed to a theme that has yet to appear in reviews. "The book is about the making of a man," he said. "It is a very serious anthropological investigation into masculinity." Taylor, who has made 44 trips into Tibet, knows the Himalayas as well as anyone, and he emphasized the rigor and seriousness with which Davis approaches his subject. "Wade brings the anthropological method to what is otherwise an adventure narrative. So it adds depth. It's not a narrative of exploits." I asked him about Davis' field methods, the way he approaches exploration in the field. Out on an expedition, Taylor said, by way of illustration, "when you arrive at camp in the evening, most people will go for the hot mug of tea. Wade goes right over to the yak herders. He doesn't sit with the other white folks."

Taylor's point was echoed by Johan Reinhard, one of the world's foremost mountaineers and explorers, who in 1995 in Peru discovered the Incan Ice Maiden mummy. "I know a lot of explorers," Reinhard told me. "I've been on a lot of expeditions, but I haven't seen many like him." There was something fitting about Davis' attraction to the early Everest expeditions, Reinhard said, because "he's like the old British explorers." Reinhard emphasized the range of Davis' abilities – his physical strength and endurance, his talents for writing and lecturing, his empathy and ability to gain the trust of his subjects – with a sense of wonder. "Wade himself is a disappearing species," Reinhard said. "He is one of a kind, a rare breed."

If Davis represents a vanishing type, perhaps it's natural that he gravitates toward others who are threatened by the long march of modernity. Indeed, here is a theme that runs like a bright thread through all of Davis' work: the spiritual and moral and aesthetic value of cultures, languages, plants, animals, whole landscapes, regardless of their practical use, a value that inheres in their very existence. This thread ties Davis to the Tibetans, the peoples of the Amazon, and those of Borneo, Australia, Polynesia – all the cultures and languages, places and landscapes that animate his books, and especially to the headwaters of British Columbia's Stikine, Skeena, and Nass rivers. It is there – on the Spatsizi Plateau, the surrounding mountains, and in the valleys, lakes, and streams radiating outward from it – that Davis' journeys really began, where he wandered as a young man, working as a ranger and a guide. Today this landscape is threatened by the global commodities boom and the heedless scramble to extract Canada's natural resources at untold environmental and social cost.

Back in the Explorers Club lounge, which itself feels like a throwback to an earlier, more heroic age, Davis and I talked about his commitment to saving the Spatsizi. Surrounded by paintings of an extinct woolly rhinoceros, an endangered polar bear, and a long-dead arctic explorer, Davis spoke of his youth guiding and fighting fires in the Canadian wilderness and of his great friend Alex Jack, a native guide whose Gitxsan name, Axtiigeenix, means "he who walks leaving no tracks." Davis' dream as a young man was to write a book about the Stikine country, and it was there that he first began to record mythology. "There was a mountain above our camp and, it's funny, because I was just back there last summer for the first time in years, and I looked up at this pyramid mountain, with these terraces on it, and I couldn't believe the memory of how fast I climbed it that time. I mean, it was this big mountain, and Alex had sent me up and said, 'Go see how fast you can climb that,' and I got there in like half an hour or something. That would take me three hours today." Alex told him to stay at the summit, without food or water, until his vision arrived. "And so I did, and then I saw something. And when I came down, he said, 'How long it take you?' I said half an hour. He said, 'Ah, pretty good. It took me 20 minutes when I was a kid.'"

Now, more than 30 years later, Davis has finally written his Stikine book, 'The Sacred Headwaters,' lavishly illustrated with photography, and he intends it to catalyze a campaign, led by the Tahltan people who inhabit that land, to save what has been called the Serengeti of Canada from live burial under more than 400 million tons of toxic tailings and waste rock generated by open-pit gold and copper mining. Mountaintop-removal coal operations are also planned, and Shell Canada was issued a lease to pursue coal-bed methane extraction throughout a vast territory. "It's not just a regional issue," said Davis, almost sputtering with outrage over the scale of the proposed devastation. "It really speaks to what's happening to wild lands all over the world."

Saving this wilderness is not just another cause for Davis – it's also about saving his home. "When I really began my lifelong engagement with the place was in 1987, when I tried to write that book again and, more important, took my wife, Gail, up there. And she fell in love with the country." She did so in spite of suffering a fairly serious injury on a long hike. "The first day out, Gail stumbled, and her heavy pack drove her face into the rocks. At first I thought she had fractured her skull. We were four days from the nearest dirt road, and it was before satellite phones." Her eyes swelled shut, and the two still had 10 days of hard walking in front of them, but Gail carried on, insisting all the while that she was fine. "It was that spirit that I fell in love with," Davis said. She still bears a scar from that trip, "a slight indentation in her forehead above her eyes." Davis, one might not guess from reading his books, is a great family man and devoted father. One of the first stories he told when we met was that he had just received a call from an NGO in Panama where his eldest daughter had been working. "Your daughter is missing," they told him. "Then we got an email a couple of hours later – by chance she wrote us – to say that she had gone off to explore a volcano." He was so proud. "When she first went down to Panama to work with the Indians, I said, 'Honey, you're only 23 years old.' She said, 'Daddy, what were you doing when you were 20?'"Listening to Davis talk about his family, his wife and daughters' love for their mountains and rivers in British Columbia, I could understand why the struggle to save the sacred headwaters is so important to him. The same could be said for the Tahltan and the other victims of modernity who just happen to live atop the minerals craved by the global commodities markets. They are fighting for their homes. But the fight is far larger than that, and Davis returned to his point that saving the Canadian wilderness, opposing environmental atrocities like the extraction of the Alberta tar sands, is not a local issue: It's a matter of stopping or slowing or at least mitigating global climate change.

There was a moment, Davis said, not so long ago, when environmentalists and scientists hoped that humanity might just run out of oil and natural gas and begin the transition to noncarbon sources of energy before we pushed the climate over the edge. Such hopes were in vain. "Now," Davis said, his voice rising, "it looks like unconventional sources are going to buy us another couple hundred years." If that happens, he continued, if we're willing to do anything, even "drilling for oil in the Sistine Chapel," as he put it, thus obliterating the most dramatic landscapes on the planet to feed our hunger for hydrocarbons and precious metals, then it's likely, because of the huge quantities of carbon released, that human civilization will succeed in destroying itself along with the Osborne caribou, red goats, Stone sheep, moose, grizzly bears, and wolves that for now still populate the Canadian northwest.