The Gobi is Earth’s fifth largest desert, sprawling across half a million square miles of southern Mongolia and northern China. It sees temperatures of minus 40°F in winter and 120 in summer, and gets just two to eight inches of annual rainfall. Some years parts of the region receive no rain at all. Windstorms sweep through day and night, with gusts strong enough to send a tent sailing away over the horizon. When winds are calm, the Gobi’s immense silence can feel as overwhelming as the heat.

Signs of life come as a surprise in this sun-blasted, wind-scoured landscape. Peering through binoculars, I at first see just barren rock rising in ranks of mountains. The only things that move are dust devils and the shimmering heat.

Slowly, as I discover where to look, animal forms emerge: A lizard rests in the thin shade of a saxaul shrub. A saker falcon lifts off from a distant cliffside. Gerbils poke their heads from burrows.

But many days pass before I finally lay eyes on the animal I crossed half a world to see: a Gobi bear, among the rarest and least known large mammals on Earth. There are perhaps no more than two or three dozen left in the wild, and none live in captivity anywhere.

This male stops at an oasis to sip water, then rests nearby. Elated by our good luck and mesmerized by the sight, my companions and I watch the bear for two hours, from late afternoon to nightfall. Most bears become active toward day’s end, but this one remains oddly still. When he finally attempts to walk, his gait seems pained and slow. He must have traveled a great distance to reach water, I tell myself, and the journey might have left him exhausted and temporarily lame.

In reality, the bear is dying. A week later a ranger finds his body near the same oasis. The old male had likely emerged from hibernation in poor condition at a time when food plants were just starting to grow.

View Images Biologists Harry Reynolds and Amgalan Luvsanjamba give a boost to Mike Proctor so he can check the level of grain pellets in a bear feeder. The Mongolian government has placed feeding stations at many desert oases in part to compensate for the loss of natural forage due to livestock overgrazing years ago.

For those working to bolster the Gobi bear’s alarmingly low numbers, the death of even one individual underscores the urgency of their task. So too do the clear signs that boom times are at hand in Mongolia. Vast deposits of minerals, precious metals, and fossil fuels are being uncovered in the country, especially in its desert. Nearly a third of the nation’s income may soon come from a massive new copper and gold mine in the Gobi. What may one day rank as the world’s largest coal mine is under development in the desert as well. The suspected mineral wealth here is so great that industry players have taken to calling this land “Minegolia.”

While storm clouds darken the Gobi bear’s horizon, there are flickers of hope. The Mongolian government declared 2013 the “Year of Protecting the Gobi Bear,” with a promise of more money for conserving the species. The Mongolian public has embraced the beleaguered bear as a national treasure, all the more precious for its rarity. Not long ago a gold-mining company sought access to protected land crucial to the bear’s survival. The government turned down the request, at least for now.

View Images The starchy, underground tuber of wild rhubarb (at left) is a staple of the Gobi bears’ diet. They also eat golden buttons, which appear after a rare rain.

The people of southwestern Mongolia have long known of the mysterious animal they called mazaalai, but credible reports were mixed with tall tales of a shaggy, humanlike creature roaming the wildest reaches of the desert. Not until 1943 did a Russian scientist-explorer confirm for the outside world that Gobi bears actually exist. Although they belong to the species Ursus arctos, commonly known as the brown bear or grizzly, their coats are often more bronze than brown and show blazes of white on the forequarters and neck. They also tend to be smaller than most North American grizzlies, whose living conditions are plush by comparison.

One genetic study suggests that the Gobi lineage is an ancient one, closer than any other to the ancestral brown bear, which first arose in Asia. Experts originally considered Gobi bears a distinct subspecies, gobiensis. However, they may turn out to be an isolated group of the subspecies isabellinus, still found in China’s Tien Shan mountains and the Himalaya.

“They’ve found a way to live in one of the most extreme environments on the planet.” —Harry Reynolds, Gobi bear expert

For Harry Reynolds, a wildlife biologist and an authority on Gobi bears, Latin labels aren’t what count. “No matter how they end up being classified, Gobi bears are unique,” he says. “They’re the only bear of any kind that dwells exclusively in desert habitat. By adaptation and learning, they’ve found a way to live in one of the most extreme environments on the planet.”

Reynolds has been a student and admirer of bears since his teens, when he apprenticed with brothers John and Frank Craighead, the godfathers of grizzly studies. He went on to spend 33 years working for the Alaska Department of Fish and Game, capturing close to 1,800 grizzlies for research and management.

In recent years Reynolds and Frank Craighead’s son, Derek, director of the science and education nonprofit Craighead Beringia South, have been teaming up with Mongolian researchers to answer some basic but urgent questions about Gobi bears: How many are left? What areas are critical to their survival? Are their numbers so depleted that they should be rounded up and bred in captivity?

View Images An immobilized bear can’t blink, so Reynolds and Luvsanjamba put protective ointment in its eyes. Like other Gobi bears, this female wore down her claws by digging through rocky soil for roots.

A misguided effort to expand livestock herding in southern Mongolia during the middle of the 20th century, when the country was a satellite state of the Soviet Union, brought more people to the Gobi, and with them more guns. Hunting and overgrazing of the desert’s marginal vegetation took a heavy toll on wildlife, and by 1980 Gobi bears had lost much of their former range and population.

One positive legacy of the Soviet era is the Great Gobi Strictly Protected Area (GGSPA), a sprawling nature preserve established in 1976 and declared a Biosphere Reserve by UNESCO in 1990. Today the reserve is the Gobi bear’s sole refuge. Access is allowed only by permission.

Invited to lead a study here in 2005, Reynolds and a team of GGSPA rangers, along with field biologists from the Mongolian Academy of Sciences, began capturing Gobi bears and fitting them with GPS radio collars. Over the next five years the team managed to collar and track ten different animals, some of them more than once. (The collars are designed to fall off after about a year.)

One unit of the GGSPA, an area labeled Gobi A, spans some 17,000 square miles. But Reynolds confirmed that most of the bears’ movements were closely bound to three minor ranges of the Altay Mountains, which make up just a quarter of Gobi A. The reason was obvious: Each of those highland areas, though separated by 40 to 60 miles of desolate desert floor, harbors several natural oases. Some of the watering holes resemble a desert wanderer’s dream—emerald havens of papyrus and poplar shading clear, spring-fed pools and streams. Others are little more than algae-clotted seeps. But even these offer enough water for a thirsty bear to drink its fill.

Spring days were gradually warming, but nights were still cold enough to freeze my water bottle when I joined Reynolds on my first expedition to Gobi A. Mornings began with hot tea followed by the roar of motorcycles as rangers left for the oases, where steel box traps had been set in hopes of capturing bears. Day after day the scouts returned with a shrug: No luck.

Although the elusive bears remained invisible, we frequently came across signs of their presence—and clues to the secret of their survival. Fresh holes revealed where bears had dug up thick, starchy roots of wild rhubarb, a staple of their diet. Still-moist dung piles contained sprouts of wild onion and bunchgrass, along with a few early wildflower blossoms. Bear droppings occasionally included bits of bone and fur from unlucky gerbils and hamsters. More commonly the dung held remnants of beetles and plump wingless grasshoppers. A picture began to form of how a grizzly might carve out a niche here at the outer edge of life’s possibilities.

Amgalan Luvsanjamba, at the time assistant director of the Mongolian Academy of Sciences, showed me nitre bushes, currant bushes, and other shrubs that would bear berries by summer—“if,” he said, “storms bring enough rain.”

“If” is the operative word when it comes to rain in the Gobi. A long, withering drought gripped the desert from 1993 to 2007, and during those years Mongolian authorities put out livestock grain at oases to supplement the bears’ dwindling food supply. The drought finally relented, but rangers continue providing the extra nourishment, though grain has sometimes been in short supply due to lack of funds.

“Bears are a kind of umbrella species. You save them, you save big chunks of habitat.” —Harry Reynolds, Gobi bear expert

Though at first it seemed impossible to me that any animal larger than a hamster could survive in the Gobi’s parched and pitiless landscape, I soon realized just how wrong I was. Following bear tracks, I often crossed those of foxes and wolves. Automatic cameras set up at the oases to identify bears also captured images of lynx and even snow leopards, one of the planet’s rarest cats. We met goitered gazelles on the flats most every day. Argali sheep roamed the hills, and ibex traversed canyon cliffs.

Often described as a wasteland, the Gobi actually serves as a stronghold for wild species pushed to the margins by people. The majority of Mongolia’s khulan, or wild asses, inhabit nature reserves in the desert. The same is true for virtually all of Asia’s last wild, double-humped Bactrian camels.

Protecting land to save Gobi bears—or any type of bear, Reynolds says—has a multiplier effect. “Bears are a kind of umbrella species. You save them, you save big chunks of habitat that benefit the rest of the wild community.”

View Images A female called Borte, after Genghis Khan’s queen, investigates an automatic camera. When first captured in 2006, Borte weighed a healthy 165 pounds. Now she has dropped to 125, probably because of the rigors of raising cubs.

At last came news that a bear had been caught in one of the box traps. Drivers fired up their Russian-made vans, and everyone, including the camp cook, piled in to jolt through canyons and over passes to the oasis. The team drugged the bear and carried it into the open. It was a male weighing 220 pounds, small as grizzlies go, but respectable for a mazaalai.

Short, dark hairs ringed the bear’s eyes. The rest of his outer coat was shaggy and of a hue that earned him the name Altan, Mongolian for “golden.” Altan’s fine underfur was brilliant white and remarkably thick.

“Winters are long here, and temperatures sink far below zero,” explained Mike Proctor, a Canadian bear expert assisting with the project. “Without deep soil to tunnel into for a den, these bears have little choice but to find a shallow cave and go to sleep partly exposed.” Lean compared with bears in more generous settings, Gobi bears likely rely on the extra underfur for insulation in lieu of body fat.

Instead of the sharp, three-inch claws depicted in many a grizzy tale, Altan’s claws had been worn short and blunt by his rocky habitat. An ordinary bear with teeth as worn as his would be judged 20 years old, but Gobi bears can’t avoid grinding sand and gravel along with their meals. Other tooth characteristics revealed Altan to be only five to seven years old. Though his was clearly a hardscrabble life, he was still a healthy young animal. We silently cheered as he woke and powered away into the hills, wearing a collar linked to a spacecraft.

That moment of celebration was followed by a long, disheartening stretch of days checking empty traps. Finally we caught another bear, a female called Borte, named after Genghis Khan’s queen. When first captured in 2006, Borte tipped the scale at 165 pounds. Now she was down to 125. Her teats held milk, which meant that she’d been transferring some of her weight to a nursing cub or possibly twins. But where was her offspring?

Borte’s drug dose wore off faster than expected and suddenly she was standing on all fours, growling, whirling, and swiping while people scattered. Though grizzlies are seldom as ferocious as popular stories portray them to be, those coming out of a drugged sleep tend to rush at the first thing they hear or see. Borte settled for destroying two pricey automatic cameras set up to record her exit.

Sophisticated gadgetry like digital cameras and GPS radio collars have revolutionized wildlife research. But it would be a mistake to underestimate the value of simple, low-tech tools.

Take barbed wire, for instance. Proctor and a young Mongolian geneticist named Odbayar Tumendemberel strung the stuff around each bait station and tacked it onto oasis trees the bears liked to rub against. The barbs snagged more than 900 hair samples for DNA analysis, which in turn yielded a trove of information. The fur turned out to be from eight individual females and 14 males. That told the scientists that the total Gobi bear population was most likely between 22 and 31.

The Gobi A mountain complex stretches 180 miles from end to end. Given the long, thirsty gaps separating the three highland areas with oases, biologists had feared the population might have divided into subgroups that no longer mixed. This would have left each enclave more susceptible to inbreeding—and to outright collapse if its last mature female died or became infertile.

Together with locations from the GPS collars and photos from remote cameras, the hair samples revealed that bears still moved between the different ranges often enough for genetic exchange to continue. The scientists could also tell from the ages of captured bears that 11 cubs born since 1999 had survived to maturity. Young Altan had bumped that number to 12.

The conclusion: Neither an extremely low population density nor a limited gene pool was preventing Gobi grizzlies from reproducing. This was crucial to know, since the alternative would be to take bears in from the wild for captive breeding. Bears might multiply in an artificial setting, but how would those born and reared there know where to find widely scattered sources of water and food when released back into the uncompromising Gobi?

View Images A young male charges an automatic camera set to record his departure from a tagging site.

Seeing distant lights from camp one night, the rangers busted a group of men who had slipped into the reserve at dark to prospect for gold. GGSPA personnel call such intruders ninja miners.

“Six years ago we had almost no ninjas,” said ranger Purevdorj Narangerel, who often patrols 600 rugged miles a week alone on his motorcycle. “Last year I arrested a hundred.” Besides occasional poaching, trespassers camp at oases, which discourages animals from coming in for water.

But the threats posed by ninja miners pale in comparison with the potential harm posed by industrial-scale mining. In addition to spawning major new transportation routes through the Gobi, mine operations will require tremendous amounts of water. No one can predict how that might affect this dry land’s aquifers, which store mainly fossil water—the precipitation from bygone centuries.

Present-day Mongolia is a proud, young democracy with 12 percent of its land in nature reserves, unprecedented new business opportunities, and billions of dollars committed to digging up treasure from the desert. Where Gobi bears will ultimately stand in this balance is impossible to say.

Though perilously low, mazaalai numbers seem to have stayed fairly stable since the end of the 1970s. There’s a faint trace of reassurance in that, but what would it take to turn the trend upward? Better funding for the Great Gobi Special Protected Area won’t answer overarching concerns about the potential impact of climate change on this part of the globe. However, a modest sum could go a long way toward improving the amount and quality of supplemental bear food at this critical period as well as purchase fuel for more frequent ranger patrols.

View Images Rangers Ankhabayar Buyankhishig (right) and Purevdorj Narangerel display metal detectors they confiscated from illegal miners who entered the reserve under cover of darkness to dig for gold.

These are soul-searching times for conservationists. So many creatures are slipping away in so many places that people who care deeply about all wildlife find themselves arguing over which ones to try to save and which to let go. Do you spread your efforts among imperiled creatures that have a fair opportunity to recover, or funnel whatever money and manpower you have toward a few species teetering on the brink of extinction, knowing they might not make it anyway? How much should you devote to a subspecies? An unusual population?

I’m not sure. What I do know is that the Gobi is one of the last grand untamed expanses in Earth’s temperate zone, and the bears’ range within it holds a world-class array of other fauna. I also know this: You can’t turn your back on a great creature in great need after getting to know it.

Which is why I rejoined the Gobi bear field team in 2012 and again the following spring. Although we caught only a single new one in 2013, it was a young male weighing more than 350 pounds, by far the heaviest of the 15 individuals radio-collared to date. The fact that a bear could grow this big and fat here at a relatively early age seemed a promising sign. Ten days later a remote camera captured an image of a female with two brand-new cubs, the first ever photographed—tiny, furry, indisputable proof of ongoing reproduction in the wild. And then a camera at another oasis recorded a different female, also with two cubs scampering behind.

We also heard rumors of Gobi bears along a ridge north of the mountain complex. One walked by a village near an oasis 60 miles east of the GGSPA. A hunter told of watching another mazaalai in a mountain range still farther away.

For bears tough enough to survive in the Gobi, maybe nothing’s implausible, and that includes one day thriving again not only in their present home but in their former territory as well.

“Look, Gobi bears might not make it,” Reynolds once told me. “But you can’t think like that. To see a problem and not want to work to fix it, not try while these bears still have a chance, well… ”

Douglas Chadwick has traveled to some of the world’s most remote corners to report stories for National Geographic. Both he and photographer Joe Riis are trained wildlife biologists.