By Scott A. Rowan
If a report published last week in “Science” magazine is correct, the oldest living animal isn’t Jonathan, the 184-year-old giant tortoise living comfortably on St. Helena, an island in the South Atlantic, but an anonymous Greenland shark, swimming sluggishly in the ice-cold waters of the sub-Arctic ocean.
Radiocarbon dating of 28 female Greenland sharks revealed that a 16-foot caught between 2010 and 2013 was at least 272 years old and could be more than 500 years old. The shark’s highest estimated age was 392 years old, with a 120-year margin of error, allowing for the possibility of the shark being 512 years old.
“I am 95 percent certain that the oldest of these sharks is between 272 and 512 years old,” Julius Nielsen told the Los Angeles Times. “That’s a big range, but even the age estimate of 272 years makes it the oldest vertebrate animal in the world.”
Jonathan, the 184-year-old giant tortoise, was considered the world’s oldest vertebrate prior to the last week’s report, whose lead author was Nielsen, a marine biologist at the University of Copenhagen. If Nielsen’s report is correct, Greenland sharks don’t reach maturity until approximately 150 years of age and routinely reach hundreds of years in age. The oldest known animal alive used to be Ming, a clam, that scientists determined was 507 years old when it died in 2006.
There are some scientists who disregard Nielsen’s report, disputing the research because part of the approach done by the researchers from the University of Copenhagen supposed that the largest sharks were the oldest.
“We know that in sharks and bony fish size is a very indicator of age,” Simon Thorrold, a biologist at the Woods Hole Oceanographic Institution, told the Los Angeles Times. “That’s why we spend millions of dollars every year to age fish – because we simply can’t use size.
Despite knowing his research has detractors, Nielsen said that he believed in the work his team did, not merely relying on the length to prove age. The radiocarbon testing the Copenhagen researchers did focused, in part, on the pulse of carbon-14 produced by nuclear tests conducted in the 1950s and its role in the development of the eye of each animal. By radiocarbon dated the eye lens nucleus from each of 28 female Greenland sharks, the scientists determined that the youngest sharks were more than 50 years old.
“We completely agree it is possible that Greenland sharks of the same size can be different ages,” Nielsen told the Los Angeles Times. “We still believe the calibration is sound and allows for an estimation (not determination) of Greenland shark life spans.”
LOCH NESS MONSTER
If the findings by Nielsen and his team are correct, it would only be one of the more unusual aspects of the Greenland shark. In addition to being poisonous for human consumption without weeks and months of curing, the species has also recently been accused of being the Loch Ness Monster.
In a 2013 episode of “River Monsters” with Jeremy Wade, researchers suggested that the mysterious Loch Ness Monster was actually a Greenland shark that made its way into the loch before the waterway was sealed, locking the large shark in the loch.