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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →The fish behind the best-known claim of a shark living for centuries is the Greenland shark, not a newly discovered Pacific fish. A 2016 study estimated that its oldest sampled shark was 392 years old, but the estimate has a wide uncertainty range: 272–512 years. Scientists inferred the age from eye tissue in sharks caught off Greenland; they did not verify the age of a living animal.
How old is the oldest Greenland shark?
The oldest specimen in the widely cited study had an estimated age of 392 years, with a 95.4% probability range of 272–512 years. The figure is an estimate, not a confirmed birthday or an exact age. NOAA’s National Ocean Service puts the distinction plainly: “Carbon dating can only provide estimates, not a definitive age.”
The finding comes from Nielsen and colleagues’ 2016 study, summarized in the Government of Canada’s 2025 COSEWIC assessment. That assessment says the estimate has not been validated with an alternative method, and uncertainty about deep-ocean radiocarbon makes the sharks’ birth dates difficult to pin down. Calling the animal “400 years old” without that qualification makes the result sound more certain than it is.
Was a 400-year-old shark found in the Pacific?
No. The age record concerns the Greenland shark (Somniosus microcephalus), a species found primarily in the North Atlantic and adjacent Arctic waters. The sampled sharks were caught off Greenland. The evidence does not support a claim that a centuries-old fish was newly discovered in the Pacific Ocean.
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The Pacific sleeper shark (Somniosus pacificus) is a related but distinct North Pacific species. It is the likely source of the geographic mix-up, not the animal behind the Greenland shark estimate. NOAA Fisheries has a separate project exploring age-determination methods for Pacific sleeper sharks; preliminary work indicates they grow substantially faster than Greenland sharks. The cited material does not establish an equivalent centuries-long age record for the Pacific species.
| Question | Greenland shark | Pacific sleeper shark |
|---|---|---|
| Where is it found? | Primarily the North Atlantic and adjacent Arctic, according to the Government of Canada’s 2025 COSEWIC assessment. | The North Pacific; NOAA Fisheries treats it as a separate species. |
| What does the cited age evidence show? | Eye-lens radiocarbon analysis produced an oldest-specimen estimate of 392 years, with a 95.4% range of 272–512 years; it remains unvalidated by an alternative method. | NOAA Fisheries describes a separate aging project and preliminary evidence of faster growth; the cited material establishes no comparable centuries-long record. |
How do scientists estimate a shark’s age?
In the Greenland shark study, researchers analyzed nuclei from the eye lenses of 28 female sharks, 81–502 cm long, as recorded in Julius Nielsen’s University of Copenhagen research record. The sharks had been caught; none was observed alive for centuries.
Proteins in the eye-lens nuclei form before birth and do not undergo the usual metabolic changes over an animal’s life. Researchers used bomb radiocarbon dating on that tissue, then applied a Bayesian calibration model to infer the sharks’ ages at birth. The method can produce an age estimate from a captured animal, but it does not turn the result into a direct measurement. In this case, uncertainty in the history of radiocarbon in deep ocean water is one reason the estimated ages have a broad range.
How deep do Greenland sharks live?
The Government of Canada’s 2025 COSEWIC assessment reports a range from surface waters to at least 2,900 m. NOAA’s National Ocean Service gives a maximum of 2,200 m. These figures differ, so the more recent Canadian assessment supports saying “at least 2,900 m” when describing the documented range; neither figure places the species in the Pacific.
Depth use also varies by observation. Nielsen’s 2017 thesis describes tracked adult females mainly using southern Greenland continental-shelf waters at 200–550 m. The 2025 assessment notes pelagic swimming and frequent excursions below 900 m in tagging records. These observations describe habitat use, not a single depth where the study’s sampled sharks were found.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why does the Greenland shark’s age matter?
The estimate points to an unusually slow life history, but a long potential lifespan should not be mistaken for a known population count or a measured global trend. NOAA notes that Greenland sharks grow slowly and are frequently caught incidentally in fishing nets and lines, making bycatch reduction relevant to conservation. The Government of Canada’s assessment says population size in Canadian waters has not been estimated and global abundance trends remain highly uncertain.
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