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The polar bears of Svalbard are at war. They pace in front of their enemy, heads swinging back and forth, claws scouring the ground. Polar bears are fearsome predators, the largest and most powerful carnivores in the world, weighing in at close a ton, with paws 12 inches in diameter and claws over 2 inches long. They are the undisputed rulers of the food chain, with no natural enemies. So what is threatening the bears of Svalbard?
Svalbard is a group of small islands located at the far north of Finland, between 74 and 81 degrees latitude – right on the edge of the polar sea. The islands are home to Ny Elesund, the world's northernmost permanent human settlement, and also home to one of the five loosely defined populations of polar bears. The polar bears of Svalbard are geographically separated from the other populations, three which are all located on or very close to North America (Alaska, Canada, and Greenland) and one of which is in Russia. The Svalbard bears, as a population, are leaner and slightly smaller than other polar bears. Their lean physique is an effect of the war the bears of Svalbard wage every day against the constantly shifting pack ice on which they live.
Polar bears, tellingly, are classified as marine mammals, like seals and sea lions, and not as terrestrial mammals. They as comfortable in the water as they are on land, but most importantly, their main food source is the sea - polar bears live mostly on a diet of seal meat, with an occasional walrus or whale thrown in for variety. But while a polar bear can swim hundreds of miles through icy waters and have keen underwater vision, they cannot capture prey while swimming. The bears must be on or near a solid surface (such as the ice) in order to launch their enormous muscle mass and utilize the full power of their killing equipment. And female bears must have a den in which to give birth and raise their young. So while the bears are dependent on the sea for food, they are equally dependent on the solid pack ice that borders it. They can live only in that small zone betwixt the two, and in Svalbard, that zone can move by many miles in a single day. Ice can form and then break up within hours, leaving some passageways open, and others suddenly blocked with treacherous shifting ice, impossible to walk on and equally dangerous to try and swim through. In addition, the pack ice shifts seasonally, and the bears must follow the icy coast as it moves south in winter and then reverses and creeps northward each summer. In order to stay in one place, the bears must walk the edge of the ice as it moves under their feet, a constant icy treadmill.
In the high summer, the ice sometimes retreats entirely from Svalbard, leaving the bears stranded on the islands. It is not an end to the war, but a long siege, of hunger and confinement. The seals go with the ice, and the bears are left with no prey. In North America, the polar bear populations have adapted to the retreat of the pack ice in summer in various ways. Some bears, famously, have become scavengers, invading human towns to root through trash, or stalking people and pets. Other bear populations gorge themselves when the ice is present, laying on extra pounds of thick fat to live on through the lean iceless summer. But the bears of Svalbard have no significant human communities to prey on, and the constant shifting of the ice keeps the bears on the move, burning the calories that the North American bears convert to fat. When the ice leaves Svalbard, all they can do is wait. They line the beaches, shoulder to shoulder, their muzzles high, facing into the wind and waiting for the ice, and their constant battle with it, to return.
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