In a study recently published in Science, a group of researchers posited that they may have found the oldest vertebrate on Earth—a Greenland shark that could be up to 512 years old. The species, also known as a gurry shark or a grey shark, is restricted to the cold waters of the North Atlantic and Arctic Oceans and surprisingly, until very recently, it was difficult for scientists to understand their lifespan.
The slow-growing shark increases in size at about 1 cm (0.39 inches) a year and can reach over 500 cm (16.5 feet), so when the research team happened upon an 18-foot specimen a few months ago, they knew they had something special on their hands. In order to estimate the age, they used a mathematical model that analyzed the lens and cornea of the shark. Of the 28 Greenland sharks analyzed, with an average lifespan of 390 years, they found the 18-foot shark could be up to 512 years old. This would date its birth to 1505, just one year before the death of Christopher Columbus.
It's important to remember that the carbon dating does have a margin of error, however, so the exact test came back with a margin of 120 years, meaning the shark could be anywhere from 272 to 512 years old. Still, it's a stunning discovery considering how difficult dating these marine animals has been, up until last year.
“Fish biologists have tried to determine the age and longevity of Greenland sharks for decades, but without success. Given that this shark is the apex predator (king of the food chain) in Arctic waters, it is almost unbelievable that we didn’t know whether the shark lives for 20 years, or for 1,000 years,” shared Steven Campana, a shark expert from the University of Iceland.
“It's important to keep in mind there's some uncertainty with this estimate,” said Julius Nielsen, a Danish marine biologist and Ph.D. student who was part of the research team. “But even the lowest part of the age range—at least 272 years—still makes Greenland sharks the longest-living vertebrate known to science.”
The exciting discovery is just one step forward in the quest to learn more about the biology of this mysterious animal.