[Animals] What is the oldest shark?

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Sharks are often called "living fossils," and for good reason: The first sharks appeared in the fossil record roughly 450 million years ago and have lived through all five mass extinctions, including the one that wiped out the nonavian dinosaurs. In addition to being long-lived as a group, individual sharks have long life spans. So just how long can sharks live, and what's the oldest shark on record?

On the lower end of the longevity scale, the great hammerhead shark (Sphyrna mokarran) lives about 44 years, although one individual caught by a fisher in Florida was estimated to be as old as 50. The great white shark (Carcharodon carcharias) can live up to 70 years, according to a 2014 study in the journal PLOS One. 

But of all the shark species, one stands out for its mind-boggling longevity. 

"The Greenland shark is the longest-lived shark species by far," Brynn Devine, a marine biologist at the University of Windsor in Ontario and an expert in Greenland shark conservation, told Live Science.

Related: The longest-living animals on Earth

Greenland sharks (Somniosus microcephalus) scour the ocean floor in the North Atlantic and Arctic. These huge sharks, some the size of great whites, are truly remarkable.

"Greenland sharks are not just the oldest sharks," Devine said, "but they are possibly the oldest animals with backbones, which is crazy to think about."

In a 2016 study in the journal Science, researchers determined that the average age of a group of 28 Greenland sharks in their sample was 272 years old. The oldest in the group was estimated to be 392 years old, plus or minus about 120 years. That led to a widely held — but now debunked — misconception that the oldest shark was 512 years old.

The oldest Greenland shark

In a 2016 study in the journal Science, researchers determined that the average age of a group of 28 Greenland sharks in their sample was 272 years old. The oldest in the group was estimated to be 392 years old, plus or minus about 120 years. That led to a widely held — but now debunked — misconception that the oldest shark was 512 years old.

But even at almost 400 years old, the Greenland shark identified in the study could have been traversing Earth's oceans around the same time the Mayflower was transporting the Pilgrims to the New World. 

John Fleng Steffensen(opens in new tab), professor of marine biology at the University of Copenhagen, was an author on the Science paper. "The age of the largest shark we have caught was between 272 and 512 years, and that was 'only' about 502 cm (16.4 feet) long. We believe Greenland sharks can be up to 550 cm (18 feet) long, and since they are growing slower the larger they are, a 550 cm long female may be maybe 100 years older."

https://www.livescience.com/what-is-oldest-shark-llm.html