Researchers using radiocarbon dating have determined that Greenland sharks, slow-moving giants that live in the cold, dark waters of the North Atlantic, are the longest-living vertebrates on Earth, with one recorded as being 400 years old.
Which explains the old Greenland shark quip that goes something like: “God must like practical jokes; why would He make it so female Greenland sharks reach their sexual peak at age 150 while males reach theirs at 75?
Lame jokes aside, the recent evidence uncovered by the team at the University of Copenhagen nearly doubles the age of oldest-known living vertebrate. The former record-holder was a bowhead whale estimated to be 211 years old, according to the BBC.
Researchers used radiocarbon dating to determine the ages of 28 Greenland sharks, and estimated that one female was about 400 years old, according to research published in the journal Science.
“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,” said lead author Julius Nielsen, a marine biologist from the University of Copenhagen.
Greenland sharks, which live farther north than any other shark species, can grow to more than 20 feet and 2,100 pounds.
Determining the age of Greenland sharks proved difficult.
“For some fish, scientists are able to examine ear bones called otoliths, which when sectioned, show a pattern of concentric rings that scientists can count as they would the rings in a tree,” according to the BBC. “Sharks are harder, but some species, such as the Great White, have calcified tissue that grows in layers on their back bones, that can also be used to age the animals.”
But because the Greenland shark is a very, very soft shark, with no hard body parts where growth layers are deposited, it was believed that the age could not be investigated, Nielsen told the BBC.
However the team discovered a means of determining the age of the sharks.
“The Greenland shark’s eye lens is composed of a specialized material – and it contains proteins that are metabolically inert,” Neilson said. “Which means after the proteins have been synthesized 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.”
The team looked at 28 sharks, most of which had died after being caught in fishing nets as by-catch.
Using this technique, they established that the largest shark – a 16-foot-long female – was extremely ancient.
Because radiocarbon dating does not produce exact dates, they believe that she could have been as “young” as 272 or as old as 512. But she was most likely somewhere in the middle, or about 400 years old, the news service reported.
It means she was born between the years of 1501, or less than a decade after Columbus landed in the Western hemisphere, and 1744, or, 12 years after George Washington was born. Most likely the date of birth was in the 17th century. If she were exactly 400 years old, she would have been born the same year William Shakespeare died.
The oldest invertebrate is a 507-year-old clam called Ming. If the female Greenland shark’s age is at the upper end of the scale, she will have outlasted the long-lived clam – and certainly had a much more exciting existence.
And, for the record, Greenland sharks, both male and female, appear to reach sexual maturity at around age 150.