An global team of scientists led by the University of Copenhagen and including the University of Oxford said the shark’s life expectancy exceeds even bowhead whales, turtles and tortoises, the latter of which can reach 100 years of age.
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Greenland sharks are the Earth’s longest-lived vertebrates – or creatures with a spine – with a lifespan that can last as long as 400 years, global researchers said Thursday.
Writing in the journal Science they said the slow-moving giant had an average life expectancy of 272 years, surpassing other species known for long life, including turtles, tortoises and some whales. That conclusion puts the entire species at the top of the longevity list. “But my guess is there are plenty of short-lived animals that are swimming around with this shark”. “Even if you look at the low end of their estimate – 272 years – that’s still substantially longer than any other documented vertebrate”.
The researchers’ findings were then matched and calibrated against radiocarbon changes in the North Atlantic’s marine food web over the past 500 years to allow them to estimate the sharks’ ages.
But such techniques can not be applied to the Greenland shark because it lacks such “hard” structures.
The centre of the shark’s eye is inactive tissue that changes very little over its lifetime. This approach, along with the extraordinary ages for these sharks, makes this study highly unusual.
They measured a life expectancy of nearly four centuries.
They used a radiocarbon dating method previously used to analyse the age of whales for the first time on a fish, studying sharks ranging in length from less than one metre to just over five metres.
Lead author, doctoral student Julius Nielsen, of the University of Copenhagen and Greenland Institute of Natural Resources, carried out the research with UiT the Arctic University of Norway, and Aarhus University.
He added: “We had to take into account the complexity of the oceans and the growth patterns of the sharks when interpreting the data from this project”. The calculation for the oldest shark does come with a rather wide margin of error, plus or minus 120 years.
‘Without the advances in statistical analysis made in recent years, it would not have been possible to demonstrate the extraordinary longevity of this species’. They concluded a gray shark they studied, which recently died, was born some 400 years ago in icy Arctic waters.
The experts already suspected the sharks could reach a ripe old age due to their large size and slow growth – the ferocious-looking fish grow no more than a third of an inch (1cm) a year.
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“I don’t know why they get as old, but I hope someone will find out”, Nielsen said.
