SVALBARD, Norway -- Born at Christmastime, cradled in pure white snow, two newborns are sleeping and suckling, protected by one of the fiercest creatures on Earth.
The brothers were born blind, toothless, a pound apiece, as feeble as kittens. For four months they will nestle in a den carved by their mother on the bleak, snowy banks of a frozen sea. They will gorge themselves on rich, fatty milk, doubling their weight every few weeks.
Etched by harsh winds and ancient glaciers, closer to the North Pole than to Oslo, Svalbard is a brutal place, unforgiving of weaknesses. From the moment of birth -- even conception -- animals here struggle against the odds. Most polar bears die before their first birthday.
Yet it is an unnatural threat -- a man-made one -- that is intruding upon this polar bear nursery. Even before they leave the safety of their dens, the cubs carry more pollutants than most other creatures on Earth, having ingested industrial chemicals from their mother's milk.
Recent scientific studies suggest that extraordinary loads of contaminants have migrated to the Arctic and are weakening polar bears and other animals, jeopardizing their survival. Like a giant sink, the remote, icy realm surrounding the North Pole -- particularly Norway's Svalbard archipelago -- collects many of the world's most toxic chemicals, especially banned industrial compounds called PCBs and pesticides such as DDT.
Scientists have also found that a relatively new contaminant -- flame retardants that are still widely applied to furniture and construction materials in the United States -- has made its way to the North Pole.
In a phenomenon called the grasshopper effect, chemicals repeatedly evaporate and fall to the ground, hopping across the world in this fashion. Riding northbound winds, they end up above the Arctic Circle, traveling thousands of miles from their points of origin in industrialized regions. Ocean currents also slowly carry chemicals north.
Once in the Arctic, the chemicals stay there. They build up in ice and ocean sediment, enduring for decades -- perhaps centuries -- and accumulate in the fat of animals, peaking at the top of the food chain.
As a result, the Arctic's most voracious predators are among the most contaminated living organisms ever found. Only Pacific Northwest orcas, Baltic Sea seals and St. Lawrence River belugas have been found with higher doses of PCBs than Svalbard's bears.
Scientists say that the globetrotting contaminants are responsible for an array of symptoms. Recent studies in Norway and Canada show that polar bears' immune cells and antibodies, needed to fight off disease, have been suppressed, and that their levels of testosterone, progesterone, vitamin A and thyroid hormones are altered by PCBs.
Although the evidence is incomplete, scientists think the pollution may be culling Svalbard's older bears and perhaps weakening or killing cubs. Females more than 15 years old are rare, and the population seems small. Researchers have also come across small numbers of strange, pseudo-hermaphroditic bears, ones with mostly female anatomy but also parts of male anatomy.
"Could you realistically put 200 to 500 foreign compounds into an organism and expect them to have absolutely no effect?" said Andrew Derocher, a Canadian scientist with the Norwegian Polar Institute who has tested about 4,000 bears in 20 years of research in the remote reaches of the Arctic.
"I would be happier if I could find no evidence of pollution affecting polar bears," he said, "but so far, the data suggest otherwise."
Sea That Never Melts
It is early evening, nine days after the return of the midnight sun, and the glaciers are casting jagged shadows on the ice below. From the front seat of a helicopter, Derocher is scanning the ice, looking for tracks. "There should be lots of bears just waiting for us here," he says.
Spring has arrived in Svalbard. Brilliant cobalt-blue seawater is shattering its icy shield, splitting the fiords into patches, like frosty white lily pads floating on a pond. But in the northern reaches of Spitsbergen, Svalbard's largest island, the sea never melts. The ice looks as taut as a bedsheet in some spots, as billowy as a down comforter in others. The horizon is lost on overcast days as shades of white blend seamlessly.
This vast, silent prairie, 600 miles from the North Pole, is a favorite spot for polar bear mothers to raise their cubs. Svalbard is home to about 2,000 bears, 10% of the world population.