What mammal has the longest life-span?

Bowhead whales can live over 200 years, longer than any other mammal. The Bowhead whale is a stocky dark-colored whale, with a length of 46-59 ft. and weighing 100 tons. Unlike the majority of whales, they do not migrate. They live their lives entirely in fertile Arctic and sub-Arctic waters. They are baleen whales. Baleen is a filter-feeding system in the whale's mouth. The whale takes in water. The whale then pushes the water out through the baleen which traps small animals which remain and become food.

The bowhead whale has suffered heavily from hunting. Being a slow swimmer and the fact that it floats after being killed, made it an attractive target. The bowhead was harvested for its blubber, meat, oil, bones, and baleen. A 1966 moratorium was placed on hunting to protect its severely reduced population. The population is rebounding though it's stressed from a greatly reduced genetic pool and environmental concerns.

Though commercial whaling is over, Native North Americans still practice subsistence level hunting of the bowhead whale. Humans are the bowhead's principal predator though killer whales also feed on them.

A 2007 discovery of a harpoon manufactured between 1879-1895 inside a recently deceased bowhead attested to its longevity. Its age was estimated to be between 115-130 years. Other bowheads were determined to be between 115-130 years old with the oldest known to have been at least 211 years old.