It may be the most unusual — and adventurous — adoption ever attempted. In the spring of 1997, naturalist Charlie Russell and artist Maureen Enns became the proud foster parents of three rambunctious daughters.

But these were no ordinary little girls: they were wild grizzly bear cubs whose mother had been killed by a hunter. And it was no ordinary adoption. Instead of trying to tame the youngsters, the new parents hoped to teach their sharp-clawed “kids” just enough to survive on their own in the rugged wilds of Russia’s Kamchatka Peninsula. The NATURE program Walking with Giants: The Grizzlies of Siberia tells the remarkable story of how this human couple went about raising a trio of bears in one of the world’s last great wildernesses. And it highlights how, through a combination of careful study and personal courage, Charlie and Maureen are forcing people to reconsider an age-old image of the grizzly bear as a ferocious man-eater who can’t live in harmony with people. They demonstrate that it is possible to learn to forge a respectful relationship with these seemingly fierce giants.

“We are carefully exploring the question of whether, by treating bears well and with respect, we can create a safe environment for both of us,” says Russell, a former Canadian rancher who has nurtured a lifelong fascination with the powerful predators. “If it is possible to truly understand and live with grizzlies, then it should be of great interest to people all over the world who are responsible for managing and preserving bears in the wild, particularly in areas close to human habitation.”

To many people, grizzlies are symbols of power and ferocity — creatures to be feared and, too often, killed. Indeed, they are awesome animals: capable of weighing 1,500 pounds, standing 10 feet tall, and running more than 30 miles an hour over rough terrain. But Russell, Enns, and others say the big brown bear, known to scientists as Ursus arctos, is too often misunderstood and maltreated. Russell, for one, believes that friction between bears and humans often stems from people’s unthinking treatment of the bears, from hunting and harassing them to feeding them from their cars and trash piles. “Most people fear bears because of a perpetual misunderstanding,” he says, “and bears fear people because of the mistreatment [they] receive due to this misunderstanding.”

Unfortunately, as human settlements have encroached on bear habitats around the world, it has become increasingly difficult to find bears that trust humans. In Europe and the United States, for example, people have all but exterminated bears from most areas: only about an estimated 1,000 bears survive in the lower 48 states, occupying less than one percent of their historic range. Biologists estimate another 40,000 or so grizzlies roam the forests of western Canada and Alaska, but these isolated populations too are beginning to feel human pressure.

But in eastern Asia, biologists believe more than 100,000 grizzlies still lope across the landscape. And some scientists say nowhere on Earth supports a denser and more isolated population of grizzlies than Russia’s rugged, volcano-studded Kamchatka Peninsula. Once, this 100,000-square-mile tongue of land astride the Pacific Ocean was considered a Siberian wasteland. The 19th-century Czars and later the Soviet dictators sent their most feared prisoners here to shiver in the freezing winters and struggle through the ferocious storms and insect hordes of summer.

But in this land of extremes, life also blossoms. Attracted by the millions of salmon that use the peninsula’s streams and lakes to spawn, grizzly bears gather by the hundreds and thousands each spring, summer, and fall to gorge themselves on fresh fish. Readying themselves for their winter sleep, they can eat nearly 100 pounds of food a day — not just fish, but a wide array of berries and other plants as well. Upon seeing this isolated bear kingdom for the first time in 1994, Russell and Enns realized they had found an ideal place to test some of their ideas about learning to coexist with wild bears. In 1996, with permission from Russian authorities, they built a small cabin on Kambalnoe Lake at the southern tip of the Peninsula. Using the cabin as a base camp, they have helped local conservationists monitor local grizzlies and protect them from poachers, traveling across the region by foot, boat, and using a small, home-built float plane piloted by Charlie. Braving the region’s world-famous bad weather, they spent long months observing dozens of nearby bears, learning how to live alongside them as just another inhabitant of the landscape.

As Walking with Giants shows, their careful observations helped the couple develop remarkably intimate relationships with the shy and sometimes playful bears. The two have learned how, when, and where they can approach the animals without alarming them. They have shown that the bears are not necessarily a threat, especially if treated with care. “We have seen some incredible things,” says Russell. Enns, however, stresses neither she nor her partner have thrown caution to the winds. “We don’t sit out there taking unnecessary risks,” she says. “We study the bears carefully and we carry pepper spray” to ward off attacks — though she is happy to report that they have never had to use it. Still, the risks are real. In 1996, for instance, prominent wildlife photographer Michio Hoshino, a veteran grizzly observer, was killed by a 7-year old Kamchatka bear that had become used to eating at a garbage dump and thus lacked the wild bear’s instinct to avoid people.

Russell and Enns hope that what they learn from walking with the giants of Kamchatka will help prevent such tragedies in the future. “We have been able to live beautifully with these animals, with no serious threat, because of what we’ve learned,” Russell says. “Hopefully, sharing what we learn will help people — and be a big help to the bear, too. It is a real problem for any species to be misunderstood.”

The moment Charlie Russell and Maureen Enns saw the three orphans in a Russian zoo, they knew what they had to do.

It was May, 1997, and the couple was visiting the animal park in Petropavlovsk, Kamchatka’s biggest city. There, in a cage, were three female grizzly cubs, recently orphaned when a hunter accidentally killed their mother. “The director of the zoo made it very clear to us that there was a death sentence on [the cubs'] heads,” the couple recall in a diary posted on their Web site. “The zoo had no money to feed them and visitors were throwing food in to them as they played behind the iron bars.”

In a moment, the cubs had “won their hearts,” the pair says. That night “we had a carrying box built for their transport” back to their wilderness cabin. Their plan: reintroduce the cubs into the wild, teaching them the basic skills they would need to survive. In this case, however, there was no manual for the new parents to follow on how to bring up the babies. They would literally be making it up as they went along. As Walking with Giants shows, however, the new family got along just fine. Russell and Enns were careful not to get the cubs, named Chico, Biscuit, and Rosie, too used to humans, instead teaching them to forage on their own and encouraging them to romp and swim independently. They did, however, keep them inside a fenced pen for some time, to protect them from adult bears who might kill the youngsters. By the fall of 1997, however, the bears had grown enough to be ready to spend the winter sleeping — and Charlie watched as they began to build a den. (Despite popular belief, bears do not actually hibernate, which involves a reduced body temperature and pulse rate; rather, they enter winter dormancy, a deep sleep from which they can be awakened, even moving to a new location if they are disturbed.)

The following spring, in 1998, “Charlie met the cubs not long after they came out of their den,” Enns recalls. And by that summer, “we were teaching our cubs to dive for dead fish. We start out in about four feet of water, see a fish on the bottom, and then chuck a rock into the pool and call the cubs over to look down in the water. One of the cubs got right in.”  The couple hopes to find their cubs safe and sound for many years to come. “We are proud of the fact that our cubs are still together,” Enns notes, especially since many experts doubted the pair could successfully reintroduce the animals into the wild. “Eventually,” she says, “we hope to see our cubs have cubs of their own,” which could happen when the bears are four or five years old.

What the future holds for the cubs and Kamchatka’s other grizzlies, however, is uncertain. The collapse of Russia’s economy has crippled many conservation and anti-poaching efforts, leaving the bears more exposed than ever to those who would kill the magnificent creatures for their skin, innards, or bones, body parts that many people believe hold magical or medicinal powers. Luckily, the economic woes have also hampered the poachers, who are having a harder time buying the fuel and equipment they need to invade the bear’s isolated wilderness territory.

The polar bear rules the north. To the hardy native people who settled the harsh lands of the Arctic, the powerful hunter with the ghostly white coat is known as the “lonely roamer.” But most of us know the huge mammal as the polar bear. And the story of how the world’s largest land predator prospers in one of Earth’s harshest environments is the subject of the NATURE program Great White Bear.

In extraordinary scenes collected across the top of the world, Great White Bear shows that polar bears are prodigious roamers indeed. Single bears have been known to trek and swim as far as 3,000 miles across icy seas and mossy, treeless tundra in search of food. Typically, however, studies suggest the bears stay within a home range that is just a few hundred square miles. Still, polar bears, by far, range over the largest territories of any bear.

The reason for the huge territories, scientists believe, is the unpredictable availability of their favorite food: ringed seals. As Great White Bear shows, populations of this common, four-foot long arctic seal can build up and melt away mysteriously, much like the ice sheets the sleek swimmers often inhabit. In good years, the bears may not have to travel far to find a seal meal. But in bad years the dark, cream-spotted animals are few and far between.

Though polar bears are excellent swimmers — their scientific name, Ursus maritimus, means “sea bear” — they usually aren’t fast enough to catch a seal in open water. Instead, in winter, the bears creep within striking distance of one of the breathing holes the seals have made in the ice. When a seal pops its head out of the hole to catch a breath, as it must do every ten minutes or so, the bear leaps and yanks the unsuspecting bather out of the water.

Sometimes, however, bears take a more direct route: as Great White Bear shows, they will crash through the top layer of the ice itself in an effort to trap the seals that may be resting in the hollow space below.

Ringed seals are a staple of the polar bear diet. In early summer, when the seals like to bask in the warming sun, hunting bears must use a different strategy. They wait until the seals are asleep and then creep close, freezing in place when the snoozers periodically open an eye to check for danger. Eventually, if the seals don’t spot the stalker, the bear gets close enough to make a powerful pounce.

More often than not, however, the seals escape: some studies have shown that bears outwit their prey less than five percent of the time.

But when the hunting is good, bears can be finicky eaters. They will easily polish off a 100-pound meal consisting of the seal’s energy-packed skin and blubber, or fat layer. But they commonly will leave much of the less nutritious muscle behind. Young bears will sometimes devour the leftovers, but it is often another Arctic inhabitant — an Arctic fox or gull — that rushes in to claim a free meal.

It can take a lot of seals to satisfy a polar bear. Males can be ten feet tall and weigh 1,500 pounds, while females are smaller, topping the scales at about 550 pounds. Remarkably, however, the huge animals can withstand lengthy periods without food. Male bears, for instance, are routinely forced to go without a major meal for three or four months each summer, when melting ice prevents them from hunting seals. And pregnant females apparently go without food for eight months — a record among mammals. Mothers even keep fasting for some weeks after their one-pound cubs, usually twins, are born between late November and January. By the time the cubs have left her care one to three years later, however, the mother has rebuilt her energy stores and is ready for another litter.

To survive their forced diets, polar bears burn a thick layer of reserve fat. In some cases, this layer can be up to five inches thick. But the blubber doesn’t just store energy: in winter, it also provides an excellent insulating blanket in temperatures that can plunge to 40 degrees below zero. Other adaptations, such as a small tail and ears and two layers of specialized heat-trapping fur, also help the bears conserve heat. In addition, each hair of a polar bear’s coat is hollow and transparent, helping to draw the sun’s rays toward the bear’s black skin. But when things get too cold, even polar bears must seek shelter, digging out snow caves in which they curl up like giant furry balls.

In summer, however, that same fat can present a problem. Polar bears can easily overheat when they run — which probably explains why they spend much of their time loping across the landscape at such a leisurely pace. In the southern part of their range, where summer temperatures can rise to levels downright blistering for bears, they may even take to the water simply to stay cool. Such strategies have allowed polar bears, which can live for 30 years, to prosper for at least 200,000 years in a challenging Arctic landscape that is by winter enveloped in icy darkness and by summer bathed by a never-setting sun.

But hunting and environmental changes, such as signs that a warming climate could be melting pack ice, may be taking their toll on the bears. And concern is growing about pollutants, such as mercury and other toxic chemicals, that are making their way into the once pristine Arctic food chain. As a result, scientists are keeping an increasingly close eye on the up to 40,000 bears that live in Canada, Russia, Alaska, Greenland, and Norway. “If a polar bear population is healthy, then one can probably safely assume that the rest of the components of that food chain are doing well,” explains a spokesman for the Canadian Wildlife Service, which has sponsored extensive monitoring studies. “However, if problems develop with polar bear populations, it may indicate problems elsewhere in the ecosystem.”

The goal, scientists involved in such studies say, is to make sure that the Arctic’s great white bear continues to roam across the top of the world.

A Texas-sized nation wedged between Russia and China, Mongolia has a long and proud history. It is especially known as the birthplace of the Mongol Empire, which lasted nearly 170 years in the 13th and 14th centuries.

200,000 years ago: The first Mongols
Early inhabitants migrate into the high rolling hills and sweeping prairies of central Asia.

1167: Birth of a legend
Temujin, who would later become the great Mongol leader Genghis Khan, is born.

1183: Ascending the throne
After leading his horseback army to victory over disparate Mongol bands, Temujin is named the Khan, or king.

1206: Empire builder
Genghis Khan unites Mongol warlords, creating an empire that begins to expand across central Asia. The horse-mounted Mongol soldiers terrified their enemies; cities often surrendered upon the sighting of a single Mongol patrol.

1227: Death of an emperor
Genghis Khan dies; his empire stretches from modern-day Hungary in central Europe to southern Russia to Tibet.

1242: High water mark
A series of new Khans invade northern China and push further into Europe. The Mongol army retreats while on the verge of conquering Vienna, due to the death of their Kahn. The army returns home in an effort to influence the selection of a new Khan.

1260: Chip off the old block
Kublai, the grandson of Genghis, becomes the new Khan.

1264: Big move
Kublai Khan moves the Mongol Empire’s capital from Karakoram in central Mongolia to Daidu, today known as Beijing, China.

1279: Consolidating gains
Kublai Khan unites China, founding the Yuan dynasty. But the Mongol Empire begins to fray at its northern and western edges.

1294: Another generation passes
Kublai Khan dies.

1368: Breakdown
The Mongol Empire disintegrates amidst infighting and attack from outside armies. Over the next few hundred years, Russia and China slowly take control of the Mongol’s former holdings.

1691: Overwhelmed
Modern-day Mongolia comes under the control of China.

1921: Revolution
After several aborted efforts to win independence from China, the Mongolian Revolution creates a new nation-state.

1930s: Sphere of influence
Mongolia becomes allied with the Soviet Union, depending on Russia for energy and economic aid.

1990
With the collapse of the Soviet Union, Mongolia becomes an independent nation.