Greenland sharks can live for centuries, outlasting the ships that first spotted them

Somewhere in the cold, dark waters of the North Atlantic and Arctic Ocean, sharks alive today may have been swimming since before the United States existed. Research into the species’ age has suggested lifespans stretching into the centuries, making it one of the longest-lived vertebrates known to science.

A Slow-Moving Giant of Frigid Waters

The Greenland shark is a large, sluggish predator found primarily in the cold waters around Greenland, Iceland, and the North Atlantic, typically dwelling at significant depths where sunlight barely penetrates and temperatures hover just above freezing. Adults commonly grow to around 10 to 16 feet long, rivaling great white sharks in size, though they move through the water at a fraction of the speed, cruising at roughly walking pace for most of their lives.

That slow, cold, deep-water existence turns out to be central to understanding the species’ extraordinary lifespan. Cold environments generally slow metabolic processes across many animal species, and the Greenland shark appears to represent an extreme example of just how far that slowdown can extend a life.

How Scientists Figured Out Its Age

Unlike most sharks, whose age can be estimated by counting growth rings in hard structures like vertebrae, Greenland sharks lack the mineralized tissue needed for that standard aging technique. Researchers instead turned to the lens of the shark’s eye, a layer of tissue that forms in early life and remains chemically unchanged afterward, effectively locking in a chemical snapshot of the conditions present when the animal was young.

Using radiocarbon dating on the proteins in the eye lens, a team of scientists analyzed dozens of Greenland sharks and estimated that the species can live for at least 250 years, with the largest specimens examined potentially reaching 400 to 500 years of age. The study, one of the most detailed vertebrate longevity investigations ever conducted, relied on a distinctive radiocarbon spike left in the ocean by mid-20th-century nuclear weapons testing to help calibrate the ages of sharks born around that period.

Older Than the Ships That First Documented the Species

A shark living several centuries would have been born long before many landmark events in modern maritime history, including the voyages of numerous historic sailing ships that first cataloged Arctic and North Atlantic marine life. A Greenland shark born in the 1600s, under the upper range of longevity estimates, could theoretically still be alive today, having outlasted generations of the wooden vessels whose crews first hauled the species up in their nets and described it in early natural histories.

That framing helps illustrate just how unusual the species’ lifespan is relative to nearly every other vertebrate on Earth, since almost no other animal with a backbone is thought to survive for anywhere close to that length of time. Even other famously long-lived marine animals, such as certain deep-sea clams or corals, that rival or exceed Greenland shark lifespans are typically simpler invertebrates rather than complex vertebrates with brains, hearts, and eyes.

A Life Lived in Extreme Slow Motion

Consistent with its extreme longevity, the Greenland shark appears to grow remarkably slowly, by some estimates less than half an inch per year, meaning it could take a century or more just to reach sexual maturity. That combination of slow growth and delayed reproduction is a pattern seen in several other long-lived species, where a low metabolic rate and calorie-limited environment favor a life history strategy built around surviving a long time rather than growing or reproducing quickly.

Greenland sharks inhabit some of the coldest and least explored parts of the ocean, often descending to deep-sea environments where food can be scarce and metabolic demands stay low year-round. Researchers believe that harsh, resource-limited setting, combined with the shark’s naturally slow metabolism, has favored an evolutionary strategy that prioritizes an exceptionally long lifespan over rapid growth, since a slower pace of living reduces the cellular wear associated with a faster metabolism.

Why a 500-Year-Old Shark Matters to Science

Findings about the Greenland shark’s lifespan have drawn considerable interest from researchers studying aging more broadly, since a vertebrate capable of surviving for centuries with a functioning heart, brain, and reproductive system offers valuable insight into how biological systems can resist the kind of cellular decline that limits lifespan in most animals, including humans. As a member of the broader shark lineage, a group of cartilaginous fish that has existed for hundreds of millions of years, the species also raises questions about how such extreme longevity might relate to sharks’ generally low cancer rates and slow aging compared with many other vertebrates.

Because Greenland sharks reproduce so slowly and mature so late, researchers have also raised concerns about the species’ vulnerability to overfishing and accidental bycatch, since a population that takes over a century to replace individuals lost to fishing nets recovers far more slowly than most commercially harvested fish. Continued study of the species’ biology, both its remarkable lifespan and its slow reproductive cycle, remains central to understanding how to protect an animal that may live longer than almost any other creature with a backbone.

This article was produced with the assistance of AI and reviewed by Morning Overview editors.

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