Experts say that the 'longest-living' shark, which has been alive since 1627, is found in the Arctic Ocean.

In 2016, researchers embarked on a comprehensive study of Greenland sharks, which scientists agree are the longest-living vertebrates on the planet.

To their amazement, during this study, they discovered a shark that had been roaming these cold waters since 1627.

But how did they figure out the age of such an ancient creature?

The researchers used a method known as radiocarbon dating to determine the ages of 28 Greenland sharks they were analyzing.

This approach led to an astonishing discovery: one female shark in the group was estimated to be around 400 years old.

Julius Nielsen, the lead author of the study and a marine biologist at the University of Copenhagen, remarked:

"We had our expectations that we were dealing with an unusual animal, but I think everyone doing this research was very surprised to learn the sharks were as old as they were."

The Greenland shark roams in the Arctic ocean Getty Stock Photo

For many years, scientists believed it was impossible to determine the age of Greenland sharks.

This belief came from the fact that researchers often rely on the growth layers in tissues found on the backbones of sharks, such as the Great White, to estimate age.

Speaking with the BBC, Nielsen said: "But the Greenland shark is a very, very soft shark - it has no hard body parts where growth layers are deposited. So it was believed that the age could not be investigated."

Despite the previous doubts, the team of researchers discovered a clever way to unlock the age mystery of the Greenland shark.

Explaining this unique method, Nielsen shared: "The Greenland shark's eye lens is composed of a specialised material - and it contains proteins that are metabolically inert."

"Which means after the proteins have been synthesised in the body, they are not renewed any more. So we can isolate the tissue that formed when the shark was a pup, and do radiocarbon dating."

Radiocarbon dating does not give an exact age, but even the lowest estimates showed just how ancient this shark truly was.

Nielsen added: "Even with the lowest part of this uncertainty, 272 years, even if that is the maximum age, it should still be considered the longest-living vertebrate,"

The shark’s incredible lifespan caught the attention of Reddit users, who shared a few lighthearted reactions.

One user joked: "That guy has no idea how much stuff has happened on land since 1627. It's a TON of stuff,"

Another chimed in with: "Bro looks tired af,", while someone else added: "Can't believe I feel bad for a shark. Imagine humans would not die we would go insane lol."