The World’s Oldest Living Vertebrate

A study published in the journal Science in August 2017 determined that the elusive Greenland Shark is the world’s longest-living vertebrate at 272 years old.

The sharks live in the deep of the North Atlantic Ocean and were once hunted for their liver oil but are now considered bycatch and not wanted. Much of the animals’ behaviors and habits were unknown because of where they lived and how reclusive they were, and one of the most pressing questions was how long the sharks lived.

The answer to the shark’s real age had previously been unknown. One shark had been tagged in 1936 and then recaptured in 1952, but only its change in size was measured. It wasn’t until 2016 that the shark’s exceptional longevity was finally discovered when scientists under Greenland’s fish-monitoring program were able to study 28 female shark specimens that had died accidentally.

Determining the age of the sharks was difficult. The age of other fish can be found by examining the otoliths, or ear stones of the fish, and the age of sharks is determined by counting the growth rings of the vertebrae and fin spines since they are made mostly of cartilage. Greenland sharks, however, have no hard structures in their bodies, so using these methods didn’t work to find their age. Scientists came up with another way of discovering the age of these particular…