In 2007, a 100-year-old harpoon was found inside the body of a bowhead whale

[Still Waters]

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.

The harpoon was an exploding lance, a popular choice in New Bedford when it was the whaling capital of the world back in the late 1800s. The patented device enabled Bockstoce and colleagues to narrow down its deployment to sometime between 1885 and 1895, putting the whale at around 115 years old. 

https://www.iflscience.com/in-2007-a-100-year-old-harpoon-was-found-inside-the-worlds-longest-living-mammal-76999