Massive slow-moving predators that dwell in the cold waters of the Arctic and North Atlantic Oceans are said to be the longest-living vertebrates on Earth, with one especially ancient individual estimated to be as much as 512 years old.
Recent research found that Greenland sharks can live upwards of 300 years, and don’t reach sexual maturity until they’re around 150.
But, for these remarkable creatures, longevity may come at a cost.
The species is often plagued by worm-like parasites that latch onto their eyes – and, these sharks have been known to enjoy an occasional meal of rotting polar bear carcass.
Massive slow-moving predators that dwell in the cold waters of the Arctic and North Atlantic Oceans are said to be the longest-living vertebrates on Earth, with one especially ancient individual estimated to be as much as 512 years old
In a study published this summer, researchers used traces of carbon-14 produced by nuclear tests in the 1950s to determine the age of Greenland sharks, by examining lens crystallines in their eyes.
The largest was estimated to be about 392 years old.
But, given some uncertainty in the method, it could be anywhere from 272 to 512 years old.
Even at the lowest estimates, however, the researchers say the Greenland sharks are Earth’s longest-living vertebrates.
Despite their amazing lifespan and elusive nature, these sharks are sometimes considered the equivalent of ‘stepping in dog poop’ when they’re accidentally caught, a biologist told The New Yorker.
Greenland sharks are bizarre-looking creatures, with ghostly eyes and ever-gaping mouths.
And, while seal are known to be among their most important prey items, these sharks also sometimes chow down on what experts have dubbed ‘polar bear steak.’
In September, Danish marine biologist Julius Nielsen, who led the recently-published study, shared a stomach-churning look at one such specimen.
The image posted on Instagram reveals the remains of a polar bear extracted from the stomach of a Greenland shark.
‘And no, I don’t think the shark attacked the bear,’ Nielsen wrote.
‘It is much more likely a carcass found by the shark. Polar bear remnants in Greenland shark stomachs are extremely rare and polar bears are considered of no importance as food source for sharks in Greenland waters.’
The species is often plagued by worm-like parasites that latch onto their eyes – and, these sharks have been known to enjoy an occasional meal of rotting polar-bear carcass. Marine biologist Julius Nielsen shared a look at this ‘polar bear steak’ on Instagram
Scientists have also noted the presence of parasites dangling from these sharks’ corneas, according to The New Yorker.
Given their incredible longevity, experts suspect Greenland sharks may hold the secrets to extending human life as well.
Researchers from the Arctic University of Norway recently sequenced the DNA from Greenland sharks – some of which were alive in the Georgian era.
Greenland sharks are found in deep water in the Atlantic Ocean, from Canada to Norway, and little is known about their biology and genetics.
The team collected DNA from tiny clippings from the fin of the sharks, which are caught on a line live, and tagged before being released.
Using this DNA, the researchers have sequenced the full genome from almost 100 Greenland sharks.
And they are now attempting to find the genes that hold the secret to why the sharks live so long.
Speaking at a conference in Exeter, Professor Kim Praebel, who is leading the study, said: ‘This is the longest living vertebrate on the planet.
‘Together with colleagues in Denmark, Greenland, USA, and China, we are currently sequencing its whole nuclear genome which will help us discover why the Greenland shark not only lives longer than other shark species but other vertebrates.
‘The results we presented here in Exeter will help us understand more about the biology of this elusive species.’
If found, the ‘long-life’ genes could shed light on why all vertebrates have a limited life span, and what dictates the life expectancy of different species, including humans.
While the researchers are still looking for the ‘long-life’ genes, their study has also shed new light on the shark’s behaviour, and how it is related to other members of its species living thousands of kilometres away.
Professor Praebel said: ‘Since the Greenland shark lives for hundreds of years, they also have enough time to migrate over long distances and our genetic results showed exactly that.
‘Most of the individuals in our study were genetically similar to individuals caught thousands of kilometres away.
‘We still do not know where and how the Greenland shark reproduce, but the results we presented here in Exeter showed that the shark may prefer to mate in deep hidden fjords of the Arctic.’
Professor Praebel added that sharks are living time-capsules that could help uncover the impact of man on the oceans over time.
Tissues, bones, and genetic data from the shark could help measure the impact of climate change on the population, when and how contaminants and chemical pollution from industry began to affect the oceans, and the extent to which commercial fishing over hundreds of years has affected the shark population.
He added: ‘The longest living vertebrate species on the planet has formed several populations in the Atlantic Ocean.
‘This is important to know, so we can develop appropriate conservation actions for this important species.’