The icon of the Arctic, the polar bear, is the ultimate survivor in one of the harshest areas on Earth. Reigning over a world of ice, tundra, and snow, this carnivore would seem to have a lineage that traces back to some mammoth creature of the icy regions.

But in fact, the polar bear’s closest ancestor is a land carnivore we associate more strongly with our forests. Over the years, scientists have uncovered an evolutionary path suggesting that polar bears are a relatively new species, and actually a subspecies, of Ursus arctos, more widely known as the brown bear. Scientific evidence has found that the brown bear, a species that also includes grizzly bears, was a “precursor” to polar bears, which then went on to develop specializations for inhabiting the harsh Arctic.

Proving their genetic compatibility, brown bears and polar bears can mate and produce viable, or fertile, offspring. It is this reproductive viability that establishes that an animal belongs within a given species. In 2006, a hybrid grizzly/polar bear, which some call a “pizzly,” was discovered in the Canadian Arctic, providing researchers proof that polar bears and grizzly bears can interbreed, even in the wild. And when researchers in Alaska compared the DNA of brown bears from around the world, looking for genetic links, they made an interesting discovery about one population of brown bears in particular. Analysis of the DNA of a distinct population of brown bears living on Alaska’s ABC islands, 900 miles south of the nearest polar bear, revealed that the ABC bears were even more closely related to polar bears genetically than they were to other brown bears.

So just when did polar bears arise as a separate subspecies? Genetic models show that the emergence of the polar bear could have taken place as recently as 70,000 years ago or as many as 1.5 million years ago. For many years, a fossil found at Kew Bridge in London was considered the oldest polar bear specimen. The fossil then placed the evolution around 70,000 years ago. But recently, scientists uncovered a fossilized jawbone from an island in the Arctic Ocean midway between Norway and the North Pole, dated to be at least 100,000 years old. Scientists believe this jawbone may represent the remains of the oldest-known polar bear, thus marking the appearance of the polar bear earlier than previously thought.

Relying on the fossil record and DNA analysis, scientists have been able to arrive at a clearer picture of the polar bear’s evolutionary path over the millennia. Some 200,000 years ago, when glaciers covered much of Eurasia, the Arctic Ocean was completely frozen. It was during this challenging period that brown bears began to wander in search of food. Approximately 125,000 years ago a population of brown bears in the far north of their range was likely split off from their brown bear ancestors, perhaps because of competition for food. The population likely became isolated by massive glaciers and, while most died in the harsh environment, those bears with an evolutionary advantage — ideal coat color and thickness for extreme cold — survived and bred. Over thousands of years, this population of bears underwent further evolutionary change, adapting even more specialized traits for surviving the harsh polar environment. When life in the North demanded teeth better shaped for ripping apart seals than munching berries, the polar bear’s molar teeth changed significantly from those of the brown bear. The bears also grew white fur, which camouflaged them in their snow-covered surroundings and gave them a hunting advantage. Scientists believe that at first these bears scavenged seal carcasses that had washed ashore, and gradually began to hunt the seals by waiting at the water’s edge as the seals surfaced to breathe. This is believed to be an important step in the evolution of a new subspecies of bear — Ursus maritimus or the polar bear.

Nature once exerted such extreme pressure on the brown bear that it eventually gave rise to a new, better-adapted subspecies, the polar bear. Now, once again, evolutionary forces are acting on this long-enduring species. As the Arctic warms, the polar bear’s unique specializations that once lent it an evolutionary edge, may now be the creature’s downfall. A changing climate may name a new king of the Arctic — the fierce and opportunistic brown bear.

Bears and humans tread common ground in NATURE’s Walking with Giants: The Grizzlies of Siberia.

Jutting into the North Pacific from Siberia, Kamchatka is a rugged peninsula of volcanic craters and steep valleys. While its impenetrability once made Kamchatka the perfect home of a notorious Soviet prison camp, its isolation also has kept it a haven for one of Earth’s last giants, the grizzly bear.

In fact, there are more grizzlies per square mile there than anywhere else on the planet. The discovery of this bear sanctuary gave two naturalists, Charlie Russell and Maureen Enns, the opportunity they’d been looking for — to live among the grizzlies and study them in close proximity to understand their true nature.

To order a copy of Walking with Giants: The Grizzlies of Siberia, please visit the NATURE Shop.

Online content for Walking with Giants: The Grizzlies of Siberia was originally posted February 1999.

It is with great sadness that I write this update to all of you.

In May of 2003, Maureen and I arrived at our cabin in Kamchatka for our eighth year in the field, studying the bears chronicled in Walking with Giants. Rosie, Chico, and Biscuit had become part of our family, and we were excited and anxious to see how they were doing. What we found on our arrival was unimaginable: a bear gall bladder hanging on the wall. At first we refused to accept this proclamation as the barbarous message it was meant to be. But as time passed and we could find no trace of any of the bears we had come to know so well, we were forced to accept the meaning of the message: While we had been away for the winter, all our wonderful bears had been killed. Maureen and I could hardly function we were so devastated.

The loss of these bears plunged us deep into grief and anger, and we have struggled to understand the nature of the slaughter. Was this horrible and incontrovertible proof that bears are more adaptable and forgiving than people are? Had these bears been killed precisely because of our success with them?

In time, we would come to understand that it was the success of the ranger program we had funded to protect our bears that ended up being their undoing. People in Kamchatka had finally been coming around to the notion that a live bear was worth more to them than a poached bear. The World Heritage Site in which our cabin sits had long been a sanctuary for poachers, not wildlife, and someone clearly wanted a return to the old status quo.

I have not given up on the work in Kamchatka. From the time I learned that the efficiency of our ranger program was threatening enough to bring about the death of our bears, I have been looking into how I can possibly keep it functioning. I will find a way to continue on my own until some organization, agency or perhaps the Russian government itself, can relieve me.

Although the South Kamchatka Sanctuary, where we have lived with our bears for eight years, has been proclaimed a World Heritage Site, without some form of substantial protection the designation is meaningless. I am determined to find a way to give this wonderful area the care it deserves. As for our ranger program, some crucial aspects of the program have to be adjusted. In the spring of 2004 I will go to Moscow, then on to the Far East to attend meetings in Petropavlovsk.

I have also long seen a need in North America to help communities coexist with bears and other wildlife. I am working on an opportunity to apply much of what our bears taught us in Russia, to our everyday living with them here. I anticipate this will keep me busy for years.

I would like to thank all of you for your letters of concern and your calls for justice. They have helped Maureen and I make it through one of the most difficult times in our lives. It’s people like you who continue to spread the word, help make this world a friendlier place and give us conviction and perseverance to stay on course. Thank you from the bottom of our hearts.

- Charlie Russell

* * *

If you’re interested in learning more about Charlie and Maureen’s bear research in Kamchatka, they’ve written two books on the subject: Grizzly Heart: Living Without Fear Among the Brown Bears of Kamchatka and Grizzly Seasons, the companion album of photos.

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.

Charlie Russell’s and Maureen Enns’s efforts to reintroduce three orphaned grizzly bears to Kamchatka is one example of the growing international efforts to restore wildlife to their rightful place in the world. But sometimes restorationists want to put predators like grizzlies back into places they haven’t been seen in centuries, sparking opposition from those who say dangerous animals just can’t coexist with people in some places anymore.

Controversy, for instance, surrounds a U.S. government proposal to reintroduce grizzly bears into the Selway-Bitterroot Wilderness areas of Idaho and western Montana. The preserves hold the largest contiguous area of suitable grizzly-free habitat remaining in the lower 48 states. More than half of those who opposed the reintroduction said in a recent poll that they fear that the bears will threaten hikers and nearby residents. But the National Wildlife Federation, which supports reintroduction, says bear attack statistics suggest such fears are unfounded. Since 1900, they note, the chance that a park visitor might be harmed by a bear is less than 1 in 2 million.

“It is important to note that encounters with the bears are infrequent because grizzlies do not naturally behave aggressively toward humans,” a group spokesman says. “Grizzlies are solitary creatures and tend not to wander beyond their home range, much less seek out interaction with people. [They] do not attack people unless surprised, protecting their food or young, or provoked by aggressive human behavior.”

“No grizzly is going to come looking for you,” adds Bud Moore, a retired forester who sides with the federation and has lived in bear country his entire life. “They don’t want to mix with people.” Moore stresses that people must learn to be respectful of bears, rather than fear them. Those who enjoy outdoor recreational activities like camping, hiking, and hunting can take some simple precautions to prevent chance encounters with grizzlies, according to the wildlife federation. For instance:

• Grizzlies are most likely to attack if they are surprised. Hikers that make noise on the trail or converse normally within a group will alert a bear to their presence long before they get close enough to frighten it.
• Wilderness users should be alert for any sign of bear activity, such as fresh tracks, droppings, or a carcass. If you do come across such a sign, it is wise to turn back or take an alternate route so as to avoid a confrontation.
• Grizzly females are very protective of their young. While they may be cute, travelers should recognize grizzly cubs as a sign of danger and avoid them at all times.
• Most importantly, be sure to store food and garbage properly when in grizzly country. Place all foodstuffs in commercially available bear-proof containers or suspend it out of reach of bears. Campers should also cook away from their campsite and sleep in different clothes than those they cooked in, as grizzlies have an acute sense of smell.

The importance of keeping grizzlies out of human food and garbage cannot be overemphasized, the National Wildlife Federation says. Bears that become habituated present a danger because they lose their shyness. Grizzlies that end up wandering around towns are bound to get into trouble, bringing tragedy to both people and themselves. But by using common sense, wilderness lovers can help make the outdoors a safer place for both bears and humans.

Studying Grizzly Bears in the Wild
http://www.cloudline.org
Details about Charlie Russell and Maureen Enns’ adventures in Kamchatka.

National Wildlife Federation: Grizzly Bears
http://www.nwf.org/grizzly/programHomepage.cfm?cpId=56&CFID;=932434&CFTOKEN;=12853333
The life and activities of the grizzly, as well as current conservation efforts and actions.

The Kamchatka Independent Ecological Group
http://www.kamchatkapeninsula.com/kieg.html
Facts and figures from this Russian conservation group.

Grizzly Bears
http://www.hsus.org/wildlife/a_closer_look_at_wildlife/grizzly_bears.html
Learn about bears from the Humane Society.

Grizzly Bear Info.
http://cmiae.hypermart.net/grizzlyinfo.htm
Extensive background information on the big bears.

The Bear Den
http://www.excite.sfu.ca/projects/exwork/best/bearden/brown.htm
Extensive links and more.

Books

Bobrick, Benson. EAST OF THE SUN: THE EPIC CONQUEST AND TRAGIC HISTORY OF SIBERIA. New York: Poseidon Press, 1992.

Hummel, Monte, and S. Pettigrew. WILD HUNTERS: PREDATORS IN PERIL. Toronto: Key Porter Books, Ltd., 1992.

McMillion, Scott. MARK OF THE GRIZZLY: TRUE STORIES OF RECENT BEAR ATTACKS AND THE HARD LESSONS LEARNED. New York: Falcon Publishing Company, 1998.

Treadwell, Timothy. AMONG GRIZZLIES: LIVING WITH WILD BEARS IN ALASKA. New York: HarperCollins, 1997.

Ward, Kennan. GRIZZLIES IN THE WILD. San Francisco, CA: Northword Press, 1994.