Scientists from Denmark have discovered that the Greenland Shark (Somniosus microcephalus) is very likely the longest living vertebrate in the world. The shark which grows to more than 6 meters (20 ft) can live up till 272 years, and possibly a hundred years more than that.
Ever since Danish fishery biologist Paul Marinus Hansen fifty years ago conducted a survey on hundreds of Greenland Sharks, they have been known to grow very old.
Hansen caught, measured and tagged the sharks, known in Inuit as eqalussuaq. When a 262 cm (8 ft. 7) shark was recaptured 16 years later it had grown a mere eight centimeter (3,1’) while another had grown 15 cm (5,9’) in 15 years.
Because of the size of the sharks it has been assumed that they lived to a respectable age. Their soft tissue made it impossible to determine their exact age.
However, modern research has shown that the nucleus of the eye lens contains tissue, that is metabolically inactive and therefore hasn’t changed since the birth of the animal.
The Danish scientists have succeeded in carbon dating the eye lenses of the Greenland Shark:
»With a 95 percent certainty we found the largest and oldest of our Greenland Sharks to be between 272 and 512 years old. Within this spectrum it is most likely that the oldest shark was approximately 390 years old,« says marine biologist Julius Nielsen from Copenhagen University, first author on an article in the prestigious magazine Science.
(English translation: Lars Rosenkvist)