The oldest known living mammal on earth may have been a giant bowhead whale that had a 130-year old harpoon stuck in its neck.

The whale was caught off the coast of Alaska in 2007. People were surprised to find a 13 cm arrow-shaped fragment dating from around 1880. This means that the whale had at the very least been able to survive being alive since that era!

Traditional whale hunters never took calves, which means it must have at least been several years old when it was first shot. The whale died soon after it was caught in 2007. Scientists speculate that it was about 130 years old. Scientists speculate that these whales may live to be as old as 200. 

(Source)