The Greenland shark typically inhabits the deep, dark waters between Greenland and the polar ice cap. At over six metres long and weighing up to 2,000 kilograms, it is the largest shark in the North Atlantic and the only shark in the world that lives under Arctic ice. Once heavily harvested for its vitamin A-rich oil — as many as 50,000 were caught annually according to a 1948 estimate — little is known about the animal.