Researchers said a Greenland shark found swimming in the Atlantic was believed to be 512 years old and could be the world’s oldest living vertebrate.
The shark’s discovery was detailed in the journal Science this week, Newsweek reported, which said radiocarbon dating on the eye lens of the Somniosus microcephalus revealed the shark could be more than five centuries old.
Scientists did radiocarbon dating on the eye lens of 28 Greenland sharks, with their ages ranging from 272 years old to 512 years, with 95 percent certainty, Newsweek said. The scientists said the oldest of the sharks, a female, may not have reached its sexual maturity until after 150 years.
Greenland sharks have been found in the North Atlantic and Arctic from eastern Canada to western Russia, Newsweek said. At times, they have even been found in the deep sea in the Gulf of Mexico.
Marine biologist Julius Nielsen of University of Copenhagen was one of the researchers who started to put together the puzzle about the longevity of the Greenland sharks in a study in 2016, National Geographic reported.
Greenland shark eye structures give the best clues to how old they are, according to National Geographic. The shark’s eye lens grows throughout its life, adding layers as it gets older.
Scientists remove all the layers that have been added over the years until they reach the center, or the embryonic nucleus, of the lens, National Geographic said, then researchers can analyze the chemical composition of the eye lens nucleus to estimate an animal’s age.
The New Yorker magazine reported last month that the mammal’s longevity just adds to their mystery, saying the answer may have to do with the animal’s slow metabolism and their cold water habitat.
“I’m just the messenger on this,” Nielsen told The New Yorker. “I have no idea.”