Greenland sharks are now known as the longest-living vertebrates on Earth, says scientists.
Researchers used radiocarbon dating to determine the ages of 28 of the animals, and estimated that one female was about 400 years old. The team also found out that these sharks grown at just 1cm a year, and reach sexual maturity at about the age of 150.
The research is published in the journal Science, with Julius Nielsen, a marine biologist from the University of Copenhagen as the lead author.
The former vertebrate record holder was a bowhead whale estimated to be 211 years old.
A 507-year-old clam named Ming holds the title of the most aged invertebrate and animal.
Greenland sharks are huge beasts and can grow up to 5m in length.
They can be found swimming slowly through the cold deep waters of the North Atlantic.
With it's leisurely pace of life and very slow grow rate, the sharks were thought to live for a long time. But still, determining any ages was difficult.
For some fish, scientists are able to determine their age by examining ear bones called otoliths, which when sectioned shows a pattern of concentric rings that scientists count, just like the rings in a tree.
Sharks, however, are harder. Some species like Great White have calcified tissue that grows in layers on their back bones, that can also be used to age the animals.
But the Greenland shark is a very, very soft shark. It has no hard body parts where growth layers are deposited. However, the team found a clever way to age them.
According to Mr. Nielsen, the Greenland shark's eye lens is composed of a specialized material and contains proteins that are metabolically inert. After the proteins have been synthesized with the body, they are not renewed anymore. And so, they can isolate the tissue that formed when the shark was a pup, and do a radiocarbon dating.
Using this technique, the team was able to establish that the largest shark, a 5m-long-female, was extremely ancient.
Though the radiocarbon dating does not produce exact dates, they believed that the shark was born between the years of 1501 and 1744, but her most likely date of birth was in the 17th century.
The team also believes that the animals only reach sexual maturity when they are 4m-long, which doesn't occur until the animals are about 150 years old.
According to Mr. Nielsen, when the size distribution all over the North Atlantic were evaluated, it is quite rare to see sexually mature females, and quite rare to find newborn pups or juveniles. With a very large amount of 'teenagers,' it will take another 100 years for them to become sexually active.
Source: BBC
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