400-year-old shark is ‘World’s Oldest Vertebrate’

A new method to determine the age of Greenland sharks showed they’re the oldest living vertebrates, with the sharks potentially reaching an astonishing 512 years old.

The age of many fish can be determined by counting growth layers of calcium carbonate “stones” found in their ears – but sharks don’t have these, and Greenland sharks lack other calcium-rich tissues that might allow analysis of age. The age of the creatures has therefore been little more than speculation up to now.

Researchers finally hit upon the idea of looking at lenses in their eyes, where protein builds up throughout their life. Radiocarbon dating of this protein offers a broad range of possible ages for each shark.

Atmospheric levels of carbon-14, the type used for radiocarbon dating, increased in the 1950s and 60s due to atomic weapons testing, and this provided a useful time stamp to scientists.

As old as the Pilgrim Fathers

Of the 28 sharks observed, most of which had died having been caught up in nets, it was assessed that the largest, a 5-meter-long female, would be the oldest and that her age was between 272 and 512. A middle point guess of around 400 years old seemed most likely.

“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,” said Julius Nielsen, a marine biologist from the University of Copenhagen and lead author of the study, published in the journal Science.

The previous vertebrate record-holder was a bowhead whale thought to be around 211 years old.

“Fish biologists have tried to determine the age and longevity of Greenland sharks for decades, but without success.” said Steven Campana, a shark expert from the University of Iceland. “Given that this shark is the apex predator (king of the food chain) in Arctic waters, it is almost unbelievable that we didn’t know whether the shark lives for 20 years, or for 1000 years.”

Some sharks are easier to age. Great Whites, for example, have calcified tissue that grows in layers on their back bones,

The Greenland shark, which hits sexual maturity at 150 years old, still probably falls short of being the oldest living of all creatures – Ming, an Icelandic clam known as an ocean quahog, was confirmed to have made it to 507 years old (before being killed by scientists).

Nevertheless, the thought that something as magnificent as a shark could have been born as the Pilgrim Fathers founded their first colony, and still be around today, is a wonderful one.

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Image credit: Julius Nielsen

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