This is scientific American 62nd Science. I'm Cynthia Graber.

By human standards, a few vertebrate species have incredible longevity.

Some tortoises live for nearly 200 years.

Bowhead whales can live even a decade or two longer.

But now there's a new champion, the Greenland shark, which conservative estimates have swimming in the seas for almost three centuries.

Julius Nielsen is a marine biologist and PhD student at the University of Copenhagen.

While on a research vessel in Greenland where such sharks were accidentally caught, Nielsen became curious about the creatures.

And perhaps the biggest of all the mysteries were how long do these sharks actually live,

because it has been expected that they can get very old, and that's based on some observations of very

very slow growth so the longevity could be exceptional and extreme but it has just

never been been possible to investigate.

That's because Greenland sharks don't have the same body structures used for gauging the age of most fish or even other sharks.

So Nielsen and colleagues used a new technique based on the lens of the eye.

The centers of the lenses can be analyzed

by radiocarbon dating to determine about when the shark was born. They tested 28 female sharks.

And what we found was that the biggest shark in our analysis and also the oldest shark was estimate the most likely single year age was almost three approximately 390 years.

Nielsen stresses that the estimate contains a fair amount of uncertainty.

Though the likeliest age is 390, the shark could be as young as a mere 272.

That still make Greenland shark the longest living vertebrate known to science.

And at the upper limit, it's possible that the shark is more than 500 years old.

The study is in the journal Science.

Also shocking, the study is in the journal Science.

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