The Greenland shark is the longest-lived vertebrate on Earth — one female was radiocarbon-dated to nearly 400 years old, meaning she was born around the time of Shakespeare. It swims at the pace of a slow walk, its flesh is toxic enough to make sled dogs drunk, and most of them are functionally blind because a parasite eats their eyes. And to age them, scientists had to find the one tissue in the body that never changes: the lens of the eye.
A full documentary on the hunt to film and study the Arctic's most elusive giant — the animal that may be older than the country you're watching from.
The quick official primer: at least 250 years, possibly over 500, living down to 2,200 meters in near-freezing dark — a metabolism so slow it borders on suspended animation.
National Geographic on the biology — 23 feet, 1.5 tons, cruising at a stroll, and the copepod Ommatokoita that dangles from its eyeballs and leaves most of them nearly blind.
OceanXplorers footage of live Greenland sharks in their element, and the researchers explaining how cold and slowness may be the secret to their staggering lifespan.
The press release that stunned biologists: Julius Nielsen's team dated 28 sharks and found one at ~392 years, obliterating the previous record held by the bowhead whale.
Britannica on what these ages actually imply — sharks alive today that predate the American and French revolutions, and why we may never know the true maximum.
Close-up encounters with the Arctic's largest fish — a ghostly, scarred, ancient animal that almost no one ever sees alive.
The original Science paper. The clever trick at its heart: the eye lens forms before birth and never renews, so its carbon is a birth certificate written in atomic-bomb fallout and cosmic rays.