Bear Trouble

Only hundreds of miles from the North Pole, industrial chemicals threaten the Arctic’s greatest predator

mother bear with a tranquilizer dart shot from the helicopter
Having stopped a mother bear with a tranquilizer dart shot from the helicopter, Derocher (with Andersen, left, and Instanes, on Spitsbergen Island) tethers the cubs and takes tissue samples to gauge the mother's exposure to industrial chemicals like PCBs. Marla Cone

Carved by harsh winds and ancient glaciers and marked by jagged mountains and fjords, Svalbard, Norway, comprises a group of islands 650 miles inside the Arctic Circle, closer to the North Pole than to Oslo. One of the last true wildernesses, Svalbard is also one of the world’s most important polar bear nurseries, though the place is so unforgiving that even under the best conditions many cubs die of starvation. Yet it is a man-made threat that now imperils the bears. Despite living in remote reaches of the Arctic, Svalbard’s bears carry higher doses of some industrial chemicals than nearly any other wild animal tested. And scientists increasingly suspect that the chemicals— especially polychlorinated biphenyl compounds, or PCBs— are harming the bears, perhaps jeopardizing their survival.

About 2,000 polar bears, perhaps 10 percent of the world’s population, inhabit Svalbard, and in April, when spring arrives and the midnight sun returns, mother bears and cubs have stirred and left their winter dens. One of the more ominous findings of recent Svalbard research is that many cubs, even before they leave the safety of their dens to confront the elements, already harbor potentially harmful levels of PCBs, absorbed from their mother’s milk.

Ice in the southernmost fjords begins to break up, revealing brilliant cobalt-blue seawater and great ice floes that look like giant white lily pads. Svalbard is desert dry, with 8 to 12 inches of precipitation a year. On overcast days in the northern reaches of Spitsbergen, the archipelago’s largest island, the fjords are still iced over and it is hard to tell where the ice ends and the clouds begin. The ice looks as taut as a bedsheet in some spots, as billowy as a down comforter in others. This vast, silent plain is a favorite spot for polar bear mothers to raise their cubs.

From the front seat of a helicopter, Andy Derocher spots fresh tracks. Even 300 feet up, Derocher, a Canadian scientist with the Norwegian Polar Institute, in Tromsø, Norway, can tell the tracks were made by a mother and two new cubs. Pilot Oddvar Instanes flies side to side, back and forth, skillfully looping and straddling the tracks, trying to follow the erratic path of the bear family. Lounging by a hole in the ice, a seal looks up, as if puzzled by the helicopter’s antics.

“She’s running here,’’ Derocher says, pointing to a row of bear tracks at the edge of a cliff. “I think she’s ahead of us.”

It is Derocher’s seventh season tracking Svalbard’s bears, monitoring their health and testing them for contaminants. He’s one of the score of people on earth who know how to find and catch a polar bear. In nearly 20 years of research in Canada and Norway, he has captured perhaps 4,000. It is no easy thing, finding a polar bear on snow. Like ice, polar bear fur is translucent, and the hollow hair shafts reflect light. It is easier to spot a bear’s tracks than to spot the bear.

Following the tracks, Derocher sees the mother and cubs right below the helicopter. In the chopper’s backseat, Magnus Andersen, his Norwegian colleague, fills a syringe with tranquilizer—the same drug that veterinarians commonly use to anesthetize a dog or cat before operating on it.He injects the pale yellow liquid into a dart and screws it onto a modified shotgun. The pilot dips to about six feet over the mother, so close he can see the coarse hair on her back blowing in the wind. Andersen kneels on one leg and opens the door. A freezing blast of air slaps him in the face. The blades whip up a frenetic whirlwind of snow, masking his view. Andersen, attached by only a thin green climbing rope, hangs out the open door. He takes aim and fires. The smell of gunpowder fills the cabin. “OK,” Andersen says. A dart sticks out of the bear’s rump. Precision is important. If he had hit her in the chest, he would have killed her.

Within minutes, the mother is starting to wobble. After another few minutes, she lies down on her stomach, panting heavily, eyes open but still, one giant paw splayed back. The cubs nuzzle her, trying to waken her, then settle down beside her. They are wide-eyed and curious as the helicopter lands and Derocher and Andersen cautiously approach on foot, their boots crunching in the crusty snow. The two men circle the bears slowly.

Derocher is a big man, 6-foot-3 and 225 pounds, but the mother bear is twice his weight. Amale bear can weigh nearly a ton. Derocher knows polar bears well enough to fear them, and he and Andersen always wear loaded .44 Magnum pistols holstered on their waists. A few years earlier, two young tourists were mauled to death by a bear outside Longyearbyen, Svalbard’s largest settlement (pop. 1,600). Now, as soon as visitors set foot in Svalbard, they are handed a pamphlet with a photograph of two bears ripping apart a carcass—seal, presumably. The animal’s entrails are exposed in a bloody pulp, and the pamphlet warns in bold red letters: “TAKE THE POLAR BEAR DANGER SERIOUSLY!” Derocher never forgets that advice. He doesn’t like being on the bear’s turf, so he watches his back. “It’s never the bear we’re drugging that’s dangerous,” he says in a Canuck accent that sounds a bit Irish in its rustic lilt. “It’s always the bear you don’t see.”

The cubs, which are about 4 months old, are as adorable and innocent as their mother is deadly. At 45 pounds apiece, they are about the size of Derocher’s 6-year-old daughter and just as harmless. Gloveless, Derocher strokes the soft fur on one, and Andersen holds out a finger for the other to sniff and lick. They are the first human beings these cubs have seen, and may be the last. Andersen gently loops ropes around their necks and tethers them to their mother to keep them from bolting. Without her, they would die.

Andersen checks the mother’s ear for an identifying tag. “She was caught once before,” he says.

“When?” Derocher asks.


Derocher sets down his black toolbox, takes out some dental pliers and opens the bear’s jaw. Leaning inside her gaping mouth, he deftly extracts a tooth the size of a cribbage peg. The scientists will use the tooth, a premolar that the bear does not need, to confirm her age. She is around 15 years old, Derocher estimates, and he says he wonders if this will be her last set of cubs. Older mother bears—over 15 years— are rare in Svalbard. Derocher suspects that chemical contaminants are to blame. (Female polar bears in the wild can live as long as 28 years or so.)

Andersen is working on her other end, using a biopsy tool to cut a quarter-inch diameter plug of flesh from her rump. Then he quickly fills a test tube with blood from a vein in one of her hind legs. A lab will analyze the bear’s fat and blood for the presence of numerous chemicals. The two scientists stretch a rope over the mother to measure her girth and length, which they then use to calculate her weight.

No matter how cold it gets, Derocher and Andersen always work with bare hands. Today is warm for Svalbard, right at the freezing mark. A few days before, they worked in minus 2 degrees Fahrenheit. They record their data with pencils because ink freezes. Every April, Derocher leaves his family for a month to work in this icy realm. He says his heroes are the 19th-century polar explorers who set out on uncharted ice, surviving years at a time with few provisions. There’s a touch of adventure to his vocation, but Derocher dismisses any comparison to explorers of old. In fact, he says, he hates the cold. “I don’t think I would last a month out here,” he says. “Not unless I had my Goretex and fleece and high-powered rifle.”

Before evaluating the cubs and taking blood samples, Derocher and Andersen inject them with tranquilizer. Derocher attaches an identifying tag to an ear on each cub. Drops of blood fall onto the snow. Derocher goes back to the mother, gently lifts her massive head and puts her lolling tongue back in her mouth. Instanes, the pilot, uses brown hair dye to paint a large Xon her rump, signaling that she shouldn’t be bothered again this year. The cubs are snoring now, all eight paws splayed out on the snow. The threesome will sleep for about two hours, then awaken, shake off the drowsiness and continue on their way. Andersen and Derocher pack up their toolbox and walk silently back to the helicopter. It has been 40 minutes since they landed.

Capturing polar bears for research can be dangerous for man and bear, but the scientists say it’s critical to understand how the animals are faring, how often they give birth, whether the cubs survive, how many industrial pollutants they carry in their bodies. Otherwise, the polar bear “would blindly stumble into extinction,” Derocher says, adding: “My job is to make sure polar bears are around for the long term.”

When bad weather sets in, or the helicopter breaks down, Derocher and his team can be stranded on the ice. Or worse. On a spring day in 2000, two Canadian colleagues tracking bears were killed when their helicopter crashed during a whiteout, a condition in which heavy clouds and snow obscure the ground. If a whiteout descends on Derocher and his crew, they throw dark-colored, rock-filled garbage bags out the helicopter window to determine which way is up.

Derocher and Andersen weigh a cub they've sedated. Marla Cone

The helicopter lifts off, heading north. Within ten minutes, Derocher has spotted more tracks—this time, a mother and two plump yearlings. Andersen fills another syringe and rests the shotgun on his leg.

Derocher, whose towering height, jet-black hair and full beard give him the aura of a big bear himself, is guided by an internal compass that steers him north, far north, whenever he craves serenity. He was raised along the lush banks of British Columbia’s FraserRiver, where he collected bird eggs and garter snakes and fished for salmon fry. He studied forest biology at the University of British Columbia and earned his doctorate in zoology at the University of Alberta. When he ventured into the Canadian Arctic for the first time as a young researcher, it struck him as barren. Then, his mentor, Ian Stirling, a polar bear expert at the Canadian Wildlife Service, dropped a hydrophone into the sea. Derocher listened to whales singing, seals grunting, ice grinding. When he heard that undersea symphony and also saw bloodstains on the ice left by feasting polar bears, he realized the place was far from being a sterile wasteland and was hooked.

The Arctic “is the end of civilization,” he says. “Far off on the ice, there is an immense sense of peace and remoteness that you can’t find in many places in the world anymore.”
Since the early 1980s, he had dreamed of studying polar bears in their purest form, of finding a pristine population, and when he first set foot in Svalbard, in 1996, he thought he had found polar paradise. The animals had not been hunted or trapped since 1973, so their population should have been booming. But something was amiss. “Things just don’t appear right,” he told colleagues within a year of arriving.

It was as if the bears were still being hunted. Where were the older bears? Why were there so few of them? Why wasn’t the population growing more quickly? A lot of cubs, he found, didn’t make it. Were they more prone to die than cubs in North America? And then Derocher came across strange, pseudo-hermaphroditic female bears with both a vagina and a small penis-like appendage. “Within the first year, it became pretty darned clear that I wasn’t working with an unperturbed population,” he says.

He began to think the reason might be chemical contaminants. Other scientists had been gathering evidence that although the world of the polar bear is as white as the driven snow, it’s not pure after all. Derocher has found the highest PCB levels in Svalbard’s male bears, with as much as 80 parts of the chemical per million parts of body tissue. (Researchers have not established a precise toxic threshold for PCBs in polar bears.) On average, male bears in Svalbard carry 12 times more of the chemical contaminant in their bodies than do male bears in Alaska. In living wild mammals, higher PCB levels have been found only in Pacific Northwest orcas, Baltic seals and St. Lawrence River beluga whales. Svalbard’s bears carry “alarmingly high” concentrations of PCBs, says Janneche Utne Skaare, of Norway’s National Veterinary Institute, who conducts polar bear contaminants research.

The snow is clean. The air is clean. Even the water is clean. So where is this toxic trash coming from? Though PCBs were banned in the late 1970s in most of the world, the compounds, once widely used as insulating and cooling fluids in electrical equipment, are remarkably persistent. In a way, climate and geology conspire to transport PCBs to the Arctic, which in the view of some scientists, is becoming a sort of giant pollution sink. Prevailing winds sweep air pollution from eastern North America, Europe and Russia northward. Svalbard in particular is something of a crossroads, buffeted by three seas and the Arctic Ocean. In a phenomenon that scientists call the grasshopper effect, PCBs from, say, a discarded transformer on the Eastern Seaboard can repeatedly evaporate in warm weather, ride the wind and fall to the ground until they’ve hopscotched to the Arctic, where they land on snowfields and in frigid seas and are trapped. The chemicals work their way up the marine food chain, step-by-step. From water to plankton to crustaceans to cod to ringed seals to polar bears—with each link, PCBs can become 10 to 20 times more concentrated. Predators at the top of the chain thus take in the highest dosages. A polar bear can carry a million times the concentration of PCBs detected in seawater. And a mother that harbors contaminants in her fatty tissue passes them on to her suckling newborn. When newborn cubs feast on their mother’s milk, they feast upon her past.

Norwegian and Canadian scientists have recently linked a variety of effects in the bears to PCBs, including alterations in immune cells, antibodies, retinol, thyroid hormones, testosterone and progesterone. The scientists don’t know what these biological changes mean to the health of individual bears or the whole population. But they have recently amassed disturbing signs of trouble.

Scientists testing bears in Canada have found that concentrations of PCBs were three times higher in denning mothers that wound up losing their cubs than in mothers whose cubs survived. Skaare speculates that pollutants are taking a toll on Svalbard’s bears, too; they seem to den more often than other bears, about every two years instead of every three, which suggests that an unusual number of cubs are not surviving.

Evidence is also mounting that PCBs are suppressing the bears’ immunity to disease. The ability to rapidly produce large volumes of antibodies against viruses and infections is critical for survival. But polar bears with high amounts of PCBs can’t muster up many antibodies, and levels of the immune cells called lymphocytes are suppressed, according to Derocher and other researchers. Bears in Canada, which carry far less PCBs, produce more antibodies than Svalbard bears. Hinting at the capacity of PCBs to weaken the immune system with disastrous effects, a distemper virus wiped out some 20,000 PCB-laden seals in Europe in 1988.

Derocher has also documented altered levels of testosterone in male bears and progesterone in female bears, and he suspects that PCBs may be the reason for the disrupted reproductive hormones. He’s trying to determine whether PCB-carrying bears are also less fertile than other bears and whether the contaminants account for Svalbard’s pseudohermaphroditic bears. (Out of every 100 female bears captured, 3 or 4 also have the genital abnormality.) PCBs also seem to deplete the bears’ reserves of retinol, or vitamin A, which is critical for regulating growth.

Some scientists say that the polar bear population is lower than expected, and they wonder if PCBs are to blame for what they describe as a missing generation. Contaminant levels in Svalbard bears peaked in the late 1970s through the early ’90s. And studies showed that the bears had seven times more of some PCBs in their bodies in the early 1990s than in 1967. At the same time, researchers have found a dearth of bears born in Svalbard when pollution levels peaked. In one study, only 13 percent of Svalbard bears with cubs were over 15 years old, compared with 40 percent in Canada. Geir Wing Gabrielsen, director of ecotoxicology research at the Norwegian Polar Institute, says it is obvious that Svalbard bears have been weakened. “Everything indicates that the polar bear is being affected by these contaminants,” he said. “There are so many indications that there are population effects.”

Yet scientists remain cautious. Peter S. Ross of Canada’s Institute of Ocean Sciences, in Sidney, who is an authority on the effects of PCBs on marine mammals, says the evidence does not necessarily establish that the contaminants have caused the bears’ problems. Wild animals face so many natural and man-made challenges that it’s almost impossible to tease out one factor as the root problem. But Ross acknowledges that PCBs (and other pollutants) correlate with changes in animal physiology and have the potential to do harm.

Ross Norstrom, an environmental chemist at the Canadian Wildlife Service, worries most about the cubs. Perhaps cubs are dying from contamination, or perhaps the effect is more subtle, like altered hormones, Norstrom says. Weighing barely a pound at birth, a polar bear cub in Svalbard is hit with a blast of PCBs from its mother’s milk right when its immune and reproductive systems are developing. Norstrom believes that now, a quarter-century after PCBs were banned in most of the world, scientists are finally on the cusp of determining exactly what sorts of harm, if any, the chemicals have inflicted on the Arctic. The overall health of Svalbard’s bears is “at best unknown,” says Derocher, largely because of the difficulties of observing them in the wild.

Just before 9 p.m. in late April, Derocher and the Norwegian Polar Institute crew are done for the day, and Instanes pilots the helicopter back to town. To the north, the clouds are closing in, threatening a whiteout, but the way south is crystal clear.

The landscape looks almost voluptuous. Curvaceous peaks are bathed in soft light, awash in hues of icy blue and frosty white. Svalbard seems almost welcoming, as if it could enfold the team in a warm embrace. The three men are glowing with the satisfaction—and relief—of knowing they are headed back to camp in Longyearbyen for a hot dinner and warm bed after a long day. They captured six bears on a tank of fuel, and all are safe, men and bears.

Derocher peers out the chopper window. “Boy, it’s pretty when the light is like this,” he says. The pilot nods.

Derocher doesn’t mention it, but this is his last foray into Svalbard. He will soon head home to Canada to conduct research on polar bears in Canada for his alma mater, the University of Alberta. Seven years in Svalbard were not enough to definitively answer the question of the bears’ future. But then, this is a place of mystery, where compasses don’t work, where summer nights look like day and winter days look like night, where sometimes you cannot even tell up from down. But Derocher has learned enough to fear for the bears; he believes that a legacy of man-made pollution promises to haunt the Arctic—frozen in time, slow to heal—for generations to come.

Get the latest Science stories in your inbox.