In 2007, Inuit whalers in Alaska made a surprising discovery. In the carcass of a whale, they found fragments of a weapon embedded in its flesh – but this wasn’t a modern piece of equipment. The harpoon was traced back to the 1900s, and after investigation, scientists estimated that the whale itself was around 115 years old, if not older. Bowhead whales (Balaena mysticetus) were severely affected by the introduction of widespread commercial whaling that saw their numbers plummet to fewer than 3,000 members. It was effectively ended by 1921, a move that has seen the population grow to between...