Scientists recently bestowed the title of oldest living vertebrate to the Greenland shark, behemoths of the Arctic that can grow as large as 21 feet (around 5 meters) long. Just how old is the Greenland shark? Estimates put one female shark of this species at around 400 years!
To put this in perspective, this shark, born sometime in the 1600s, was alive even before the Pilgrims arrived at North America in 1620. It would also mean this shark was around 250 years old at the time of the American Civil War.
How did scientists date the shark's age, given that this species doesn't have much hard body parts with clear calcified layers? With a bit of a detective shrewdness, scientists at the University of Copenhagen found that the lenses of the shark had proteins that are metabolically inactive. "Which means after the proteins have been synthesised in the body, they are not renewed any more. So we can isolate the tissue that formed when the shark was a pup, and do radiocarbon dating," said Julius Nielsen, a marine biologist who led the study.
Being so old and big means that the shark grows very little each year. In fact, it grows only about one-third inch (1 cm) per year. Scientists also estimate that it reaches sexual maturity at around the 150 year mark - well beyond the entire lifespan of many other living vertebrates, including us!
Are there creatures that live longer? Perhaps. But until researchers find proof otherwise, the Greenland shark will bear the well-deserved title of oldest vertebrate. If you were wondering, the title of oldest invertebrate belongs to a 507-year-old clam named Ming.