The Greenland shark grows about one centimetre a year, does not reach sexual maturity until around age 150, and a specimen carbon-dated by Danish researchers in 2016 was estimated to be at least 272 years old, meaning it was already swimming the North Atlantic when Mozart was composing symphonies.

As soon as marine naturalist Julius Nielsen tempted the contour from the eye of a five-metre Greenland shark in his Copenhagen laboratory, he was hosting tissue that had launched forming before the United Claims existed. The healthy and balanced proteins in his hands had been staked down at some time in the 1600s — perhaps earlier still. They had survived three centuries or a lot more of swimming using direct-funky Arctic marine, and also they were about to render Somniosus microcephalus the lengthiest-resided vertebrate ever recorded.

The fear Nielsen had broken was one that had bested shark conservationists for a century: how execute you date an creature that vacates most clearly no heighten rings?

The dating fear

Sharks are notoriously hard to period. Bony fish leave heighten rings in their ear rocks; trees leave them in trunks. Sharks have neither. Their skeletons are cartilage web content, and also Greenland sharks in picky have most clearly no calcified vertebrae to matter. For years, the species’ lifespan was presumed at from indirect indications — Danish whalers in the 19th century sensed the terribly same marked civilization turning upwards in their webs year after year, however most clearly no one might ranked a figure on it.

Nielsen’s team went for the eye. The contour of a vertebrate eye includes healthy and balanced proteins staked down before birth that never ever retrieve amended. If you can date those healthy and balanced proteins, you can date the creature.

The weakness was radiocarbon. Atmospheric nuclear bomb appointments in the 1950s and also early 1960s swamped the earth using carbon-14, disowning a sharp impale — the so-discussed bomb pulse — in the tissue of anything active at the time. Youthful sharks in the study towed the bomb-pulse signature in their lenses. Older sharks did not, which recommended they had been born before the mid-1950s. The best specimen predated the signature by a wide margin.

The figure Nielsen immigrated at

In August 2016, Nielsen and also his spouses uploaded their result in Science: a Greenland shark towed upwards as bycatch in the North Atlantic, carbon-dated to a selection of 272 to 512 years, using a the majority of-probable middles of 392 years. The original record, “Eye contour radiocarbon discloses centuries of long life in the Greenland shark,” appeared in Science on August 12, and also the institutional press let loose from co-author Richard Brill’s laboratory at the Virginia Institute of Marine Science strolls using the method. The central price estimate places the oldest viewer’s birth in the early 1600s — steady using Galileo’s later telescopic work.

To retrieve there, Nielsen had to equalize a heighten contour against the bomb-pulse advice times from the vibrant sharks in his instance. The species grows approximately one centimetre per year. Massaging backwards from a five-metre figure and also a heighten contour that flattens using period, the math alluded to the early steady period. NPR’s contemporaneous coverage strolls using the calibration in unvarying language, and also a 2017 Reside Science description spells out what the irresoluteness pubs usually routine.

A spirit resided at 29 levels Fahrenheit

The maladies that obtained Nielsen’s dating strategy work are the terribly same maladies that obtained the shark antiquated in the first void. Greenland sharks stay in marine that hovers in between approximately minus one and also four levels Celsius. They cruise the deep North Atlantic and also Arctic, sporadically surfacing direct Greenlandic and also Icelandic coastlines in winter. Their travelling pace is slower than a nonchalant human stroll pace.

Everything about the creature runs slow-sliding. Metabolism, heighten, recreation, also the firing of courages. Funky-marine physiology owns been the kneading description for their long life because the 19th century — however the kneading description is not the terribly same as a product, and also that hole is what the contour examples have opened upwards.

What the eye is still divulging

The contour-dating strategy was the onset, not the end. As soon as Nielsen had authenticated the critters were that antiquated, the famous next misgiving was what preserved them functioning. A decade of heed-upwards study owns integrated on a solitary counterclaim: an unusually predacious seated of DNA-recover paths.

In January 2026, Dorota Skowronska-Krawczyk, an affiliate professor of physiology and also biophysics at the University of California, Irvine, uploaded a study in Nature Correspondences on the Greenland shark’s visual mechanism. Her team inspected retinas from critters upwards to approximately 130 years antiquated, contrasted them against bovine and also human eyes, and also ran the shark’s genome against five other shark species. The retinas unveiled most clearly no noticeable decrease. The visual mechanism is intact, acclimated for dim light, and also reportedly preserved that way by bolstered DNA-recover gizmos, also in critters whose corneas are routinely colonized by parasitical copepods. UC Irvine’s writeup of the record and also Science Friday’s January 2026 meeting using Skowronska-Krawczyk lay the findings out for a basic target bazaar.

The contour examples are not merely clocks, in other words. They opened a programme of study into which botanical mechanisms in the shark wear out first, and also which ones can be coaxed to last longer. The existent say of that work overlaps using existent genomic results: a 2024 chromosome-scale setting upwards of the Greenland shark genome, uploaded on bioRxiv by an global team led by Arne Sahm at Ruhr University Bochum, detected widened gene families for DNA recover and also immune impartial, along using structural corrections in TP53, the tumor-suppressor gene that does identical work in elephants.

What the terribly same strategy owns disclosed about the species

Applied across Nielsen’s instance, the contour-dating strategy amassed a lot more than a solitary headline figure. It amassed the first creditable heighten contour for the species — and also using it, the unsettling discovery that female Greenland sharks execute not reach sex-related maturation until about 150 years antiquated, at a figure length of approximately four metres. Nielsen’s spouses ranked the figure a lot more accurately at 156 years, plus or minus 22.

That figure is itself a item of the dating work. Without a way to period the critters, most clearly no one had know as soon as they incubated. Now that the contour exists, it owns reframed every preservation misgiving fastened to the species. A shark collared in a longline today might be a young x-rated by her species’ clock, years from her first clutter. Historic Greenlandic and also Icelandic fisheries that collected the species for liver oil using the early 20th century were, it turns out, detaching critters that had not yet recreated — and also would most clearly not have, for an additional human lifetime.

The meat itself is ruining as soon as fresh, due to high increases of trimethylamine oxide and also urea, and also is lone edible after months of recovery and also troposphere-drying out, the basis of the Icelandic recipe hákarl. That toxicity is arguably the lone excuse the species was not fished to collapse before anybody provided how gradually it grew.

Why the strategy crunches past one shark

Greenland sharks have come to be a quiet centre of gravity in comparative gerontology — the study of why some species period gradually and also others period rapid. The bowhead whale resides past 200. The sea quahog clam, an Icelandic specimen nicknamed Ming, was dated to 507 years. Greenland sharks rest at the peak of the vertebrate list, and also they rest there because Nielsen detected a way to authenticate it.

The eye-contour strategy is now being acclimated for other long-resided species in which perfunctory aging philosophies autumn short. And the healthy and balanced proteins themselves are being read for what they can tell scientists about cataract development, cancer resistance — the Sahm team’s genome work claims the shark’s bolstered DNA-recover networks and also befouled TP53 route might clarify how 400 years of cell department can pass without gleaning noticeable malignancies — and also the straightforward biochemistry and also biology of botanical time.

None of this would most clearly exist without a solitary insight: that the counterclaim to an indisputable misgiving was sitting, unharmed and also unmodified, within the eye of the creature with one voice along.

Yielded using AI help. Swiped an additional kind at by the Earn Technology Less complicated editorial team before publication. Consultation our editorial manifesto and also about page.

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