Somewhere between 200 and 2,600 metres beneath the surface of the North Atlantic, a shark the length of a small car is moving at roughly the pace of a person walking through knee-deep snow. It is grey, blunt-nosed, and probably older than the United States. Two milky tendrils may trail from its eyeballs — a parasitic copepod called Ommatokoita elongata, latched onto the cornea and slowly clouding the surface. The animal can lose much of its vision and still keep moving through the dark.
The Greenland shark, Somniosus microcephalus, is the longest-lived vertebrate on Earth. A 2016 study led by researchers at the University of Copenhagen and published in Science put the species’ lifespan at a minimum of 272 years, with the oldest individual in the study estimated at 392 years, plus or minus 120 years. The two largest sharks in that study, measuring 493 and 502 centimetres, were estimated to be 335 and 392 years old respectively. The larger of the two may have been a pup when Isaac Newton was still drafting the Principia Mathematica in his rooms at Trinity College, Cambridge, in the mid-1680s.
How to date a shark that has no bones to count
Sharks have cartilage instead of bone. There are no growth rings to slice open, no otoliths like the ones biologists pull from fish ears to read like tree stumps. For decades, nobody could say with much confidence how old a Greenland shark actually was — only that the animal seemed to grow so slowly that the usual rules of age and size did not quite apply.
The breakthrough came through radiocarbon. Between the 1950s and early 1960s, atmospheric nuclear testing sent a spike of carbon-14 into the environment. That signal moved through air, water, and living tissue. Biologists call it the bomb pulse, and it can act as a chemical timestamp in tissues that formed during that period.
Researchers at the University of Copenhagen and their collaborators studied the eye lenses of 28 female Greenland sharks caught accidentally by commercial fishing vessels. Eye lenses are unusual: their inner proteins are laid down before birth and are not replaced in the same way as many other tissues. Peel a lens back to its core and you are holding tissue that dates back to the animal’s earliest development. The method drew on work by Jan Heinemeier, John Fleng Steffensen, and Julius Nielsen, whose Greenland shark work helped turn an old biological hunch into a measurable age estimate.
The team’s headline finding — that the oldest individual was at least 272 years old and plausibly far older — made the species the record-holder among backboned animals, beating the bowhead whale by more than a century.
Not everyone is convinced the top of the range is exact. Some biologists have pointed out that the deep, cold water Greenland sharks inhabit mixes slowly, meaning the bomb-carbon signal may not move through that environment the same way it does elsewhere. That could affect the highest age estimates. The exact ceiling is still argued. The floor is already extraordinary.
A shark that becomes a teenager at 150
Everything about the animal moves slowly. Females are estimated to reach sexual maturity at roughly 150 years old and around four metres long. A Greenland shark alive today that is capable of reproducing may have been born sometime around the Victorian era.
Adult length can run to about seven metres. Weight can approach a tonne. BBC Wildlife Magazine notes that some individuals cruising the North Atlantic today may have been born around 1625 — the year Charles I became King of England and the Dutch West India Company was founding New Amsterdam on the southern tip of Manhattan.
Cruising speed is about 0.3 metres per second. A person on a leisurely walk moves several times faster. There is video of divers overtaking them without effort. Their metabolism is so slow that a meal appears to last months. Stomach contents pulled from captured sharks have included seals, reindeer, polar bear remains, and horse bones — much of it probably scavenged from carcasses that sank rather than chased down in open water.
The parasite on the eye
Many adult Greenland sharks carry Ommatokoita elongata, a parasitic copepod that anchors into one or both corneas. The copepod is pale, narrow, and long enough to be visible when it dangles from the eye. It embeds itself into the corneal tissue and can cause severe visual impairment.
Infection rates in some surveys are extraordinarily high. The sharks appear to lose much of their useful vision and to keep hunting and navigating anyway, presumably using smell, mechanoreception through the lateral line, and electroreception via the ampullae of Lorenzini — the gel-filled pores clustered around the snout that detect faint electrical fields produced by other animals. In water below 4°C, at depths where sunlight is faint or absent, eyes are only one part of the instrument panel.
There is a curious wrinkle here. Recent work on the Greenland shark visual system suggests that the underlying retina may remain surprisingly functional over long periods, even as parasites damage the outer surface of the eye. The animal may not be simply blind in the ordinary sense. It may be carrying a long-lived visual system behind a badly scratched window.
What the genome is starting to reveal
In 2026, researchers led by Shigeharu Kinoshita at the University of Tokyo reported a near-complete Greenland shark genome sequence. The team recovered most of the genome and started finding what long-lived species often force scientists to look for: systems for maintaining DNA, regulating stress, and limiting cellular damage.
The researchers flagged several findings in particular. First, they reported unique amino-acid substitutions in linker histone proteins, which help spool DNA into chromatin. Those substitutions may stabilise the packaging of the shark’s genome and slow the accumulation of damage. Second, they found expansion of gene families involved in immune response and DNA repair. Third, they reported an expansion of ferritin genes, which govern iron storage and may help control oxidative stress and ferroptosis, a form of iron-dependent cell death.
The genomic work does not point to a single magic longevity gene. It points instead to maintenance: genome stability, iron metabolism, immune function, stress resistance, and cancer suppression working together over an animal lifetime that can stretch across human empires.
The Space Daily team has covered how these sharks live for hundreds of years from the ecological angle. The genome now lets biologists ask what is happening at the level of individual base pairs.
Why the Arctic, and why so slow
Cold is part of the answer. Greenland sharks live in water that can hover around freezing. Chemical reactions run slower there, including some of the reactions that damage cells. Their metabolism is among the slowest measured for a fish of comparable size, and their pace of life seems matched to the deep, dark water they inhabit.
Their range extends from the North Atlantic up under the Arctic ice and, apparently, into places nobody expected. Researchers tagging tiger sharks off Belize once accidentally caught one — well outside its assumed territory. Reports about sharks thought to have been born in the 1600s still go viral because most people have no intuitive category for an animal that old still moving through the ocean today.
The comparison that puts it in perspective
Bowhead whales live about 200 years. Galapagos tortoises can reach around 175. Rougheye rockfish can push past 200. The only vertebrate that comes close to the Greenland shark’s ceiling is itself. Among all animals, the ocean quahog clam (Arctica islandica) is one of the few individual animals confidently known to exceed it, with a recorded age above 500 years.
Line up the human timeline against a single 392-year-old Greenland shark and the arithmetic gets strange. That shark was born before the invention of the steam engine, before the founding of the Royal Society, before Bach was born. It was already a century old when the American colonies declared independence. It was middle-aged when Darwin sailed on the Beagle. It was reaching sexual maturity around the time Marconi sent the first transatlantic radio signal.
The late John Fleng Steffensen of the University of Copenhagen spent much of his career helping turn the Greenland shark from a curiosity hauled up in fishing gear into one of the most important animals in longevity biology. The work by Steffensen, Heinemeier, Nielsen, and their collaborators made it possible to treat the shark’s lifespan not as folklore, but as a scientific problem.
Somewhere out there tonight, a Greenland shark that was born during the reign of Charles II may be drifting through black water at walking pace, guided by smell and the electrical pulse of something small moving nearby, its corneas clouded by a parasite and its genome carrying clues scientists are only beginning to read. It has already outlived nations. It may still have another century to go.