Greenland Sharks Live Centuries

In the frigid, deep waters of the North Atlantic and Arctic Oceans, a creature swims that may have been born during the time of Shakespeare. The Greenland shark's extraordinary lifespan is a direct result of its extreme environment. The icy, dark water dramatically slows down its metabolism, leading to a life lived in ultra-slow motion. This glacial pace is evident in its growth rate of only about one centimeter per year. To put their timeline in perspective, these ancient animals don't even reach sexual maturity and begin to reproduce until they are around 150 years old, a period longer than the entire lives of most other vertebrate species.

For decades, the true age of these sharks was a mystery, as their soft, cartilaginous skeletons lack the growth rings scientists typically use for age estimation. The breakthrough came from an ingenious analysis of their eyes. The proteins in the core of a Greenland shark's eye lens are formed before birth and remain unchanged throughout its life, creating a perfect time capsule of the ocean's chemistry from its birth year. By using radiocarbon dating on these inert proteins, researchers were able to accurately pinpoint the age of numerous sharks, with the oldest in one study estimated to be at least 392 years old. This discovery firmly established the Greenland shark not just as a curiosity, but as the undisputed longevity champion of the vertebrate world.