The Shark That Doesn't Hit Puberty Until Age 150

Deep in the frigid waters of the North Atlantic and Arctic Ocean swims a creature that makes the concept of "aging gracefully" feel like a dramatic understatement. The Greenland shark can live for more than 400 years, officially earning the title of longest-lived vertebrate on the planet. A 400-year-old Greenland shark would have been a pup back when people were still debating whether the Earth was round.

Here is the part that really scrambles your brain: Greenland sharks do not reach sexual maturity until they are around 150 years old. Imagine going through puberty at 150. That is not a coming-of-age story — that is a geological event.

They grow at less than a centimeter per year, which is the animal equivalent of watching paint dry while the paint is also somehow still alive and completely unbothered. Scientists figured out their age by radiocarbon dating the proteins in the lenses of their eyes — lenses that form at birth and never change, like a biological time capsule sealed in a very large, very old fish.

They are also nearly blind, often host parasites permanently attached to their eyeballs, and cruise through the deep dark at a leisurely two miles per hour. None of this seems to trouble them. Apparently, if you plan on living for four centuries, there is simply no rush for anything.