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This is Scientific American 60-second 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 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.

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