If it was clear to David and Bella Kuptana what had happened to their hunting cabin on Victoria Island in the Arctic Archipelago last spring, it’s because there was a bear-shaped hole in the wall. Tracing the frozen coastline on snow machines, they found five more cabins in a similar state of ruin; behind one that appeared untouched, they spotted the rogue, making a break for the open plain. David, who took down his first polar bear when he was nine years old and has killed as many as three a year since then, felled the animal with his first shot, and immediately knew something was wrong. Its head was unusually wide, and its paws were brown. Except for all that matted white fur, it looked more like a grizzly.