In the cold, dark waters of the far North swims a shark so slow and so long-lived that individuals alive today may have been born before some of the world’s oldest nations existed. Scientific dating of these animals suggests a lifespan measured not in decades but in centuries, placing them among the longest-lived creatures with a backbone.
A shark built for the deep cold
The Greenland shark is a massive, sluggish predator of the North Atlantic and Arctic, where it cruises through frigid water that would slow almost any other large fish to a crawl. Adults can grow to great size, reaching lengths comparable to a great white, yet they move with a famously unhurried, almost drifting motion.
That slow pace suits an animal adapted to the deep and the cold, where energy is scarce and metabolism runs low. Its coloration is a dull gray to brown, and its body is thick and heavy, better suited to endurance than to bursts of speed.
Life in near-freezing water shapes almost everything about the species. A cold environment slows the chemical reactions that drive an animal’s body, and the Greenland shark appears to have leaned fully into that reality, trading speed and rapid growth for a metabolism that ticks over at an extraordinarily unhurried rate. Many of its most remarkable traits, from its longevity to its languid movement, flow from that basic adaptation to the deep cold.
Dating a life span in centuries
The claim of extreme longevity does not rest on guesswork. Because the Greenland shark lacks the hard, bony structures that scientists normally use to age fish, researchers turned to the tissue of the eye lens, which forms early in life and preserves a chemical record. By applying radiocarbon dating to that tissue, they estimated ages reaching into the hundreds of years.
Those estimates pointed to a lifespan that can stretch to roughly four centuries, making the species the longest-lived vertebrate known to science. An overview of its biology and the aging research is maintained by NOAA Fisheries in its profile of the Greenland shark.
Growing at a glacial pace
Extreme age comes paired with extreme slowness in growth. Greenland sharks add only about a centimeter to their length each year, which means reaching full size is the work of many decades. That crawl toward maturity has a striking consequence: the animals are thought not to reproduce until they are well over a century old.
Such a late start to breeding shapes everything about the species’ vulnerability. A population that takes generations to replace itself cannot bounce back quickly from losses, which makes the sharks especially sensitive to being caught, whether deliberately or as bycatch.
A diet, and a body, full of surprises
The Greenland shark is an opportunistic feeder, taking fish and marine mammals and scavenging carcasses that sink to the depths. Its flesh contains high levels of a compound that is toxic if eaten fresh, which is why traditional preparation in the far North involves lengthy fermenting and drying before it is considered safe.
Many individuals also host a small parasitic organism attached to the eye, a peculiarity that has fascinated observers. A wider account of the shark’s habits and its record-setting age appears in the reference on the Greenland shark.
Living history beneath the ice
The staggering ages involved turn each animal into a kind of living archive. A large Greenland shark encountered today could plausibly have been swimming the Arctic for the better part of four hundred years, meaning its life overlaps with vast stretches of recorded human history.
That framing is more than a curiosity. Long-lived animals accumulate a lifetime of exposure to their environment, and studying them can offer clues about how conditions in the deep ocean have changed over centuries.
Why longevity makes conservation urgent
The same traits that make the Greenland shark extraordinary also make it fragile. Slow growth, late maturity, and a centuries-long lifespan mean that removing adults from the population has outsized, long-lasting effects, because replacements take so long to arrive.
History compounds the concern. The species was once targeted heavily for the oil in its liver, and although that fishery has faded, the animals are still caught unintentionally in nets and lines set for other species. For a shark that may not breed until it is more than a century old, even a modest, steady loss of adults can quietly erode a population long before the decline becomes obvious.
Protecting a species that measures its generations in human lifetimes calls for caution well beyond what faster-breeding fish require. The Greenland shark’s remarkable endurance, in other words, is exactly what leaves it exposed, and what makes careful stewardship of the cold northern waters it inhabits so important.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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