In parts of the Arctic, polar bears are in decline as sea ice, which they depend on to hunt, disappears. That is not the case, however, on the Norwegian island of Svalbard, where bears have actually managed to grow more plump even as ice melts away. In parts of the Arctic, polar bears are in decline as sea ice, which they depend on to hunt, disappears. Polar bears hunt by stalking sea ice in search of seals, but sea ice is shrinking across much of the Arctic, which is warming nearly four times faster than the world as a whole. A study along the western edge of Hudson Bay, in Canada, found that, over the last half-century, the number of polar bears in the region dropped nearly in half, and the bears grew measurably smaller.