The Greenland shark can live 400 years, older than the United States itself

The Greenland shark is a slow, cold-water predator that most people will never see, yet it holds one of the most extraordinary records in the animal kingdom. A landmark study estimated that the species can live for roughly four centuries, which would make an individual alive today potentially older than the United States. That single finding rewrote the record books, pushing the Greenland shark past whales and giant tortoises to claim the title of the longest-lived vertebrate known to science.

What makes the claim so striking is not just the raw number but the biology behind it. These sharks grow at a glacial pace, mature only after more than a century, and drift through the frigid depths of the North Atlantic and Arctic in a way that seems almost designed to stretch a lifespan across human history. Confirming their age required a clever workaround, because a fish that lives for hundreds of years leaves behind almost nothing that can be counted like tree rings.

Reading age in the shark’s eye lens

Most fish can be aged by counting growth bands in hard tissues such as ear stones or fin spines, but Greenland sharks have soft bodies with no such structures to read. To get around that, researchers turned to the one part of the eye that forms before birth and never turns over: the crystalline center of the lens. Because that tissue is metabolically inert and is laid down earliest, its chemistry preserves a snapshot of the environment from when the animal was still an embryo. The research team applied radiocarbon dating to the eye lenses of 28 female sharks collected as bycatch to work backward to each animal’s birth.

The analysis leaned on an unusual historical marker. Nuclear weapons tests in the 1950s and early 1960s flooded the oceans with a pulse of radioactive carbon, and that spike shows up in the tissue of animals born afterward. Sharks whose lens cores carried the bomb-pulse signature were relatively young, while those without it had to be older, giving the team a fixed calibration point to anchor the rest of their estimates.

What 400 years actually means for one animal

The results were staggering even to the scientists who produced them. The study put the average lifespan of the sampled sharks at least 272 years, and the two largest animals, measuring roughly 16 feet, were estimated at about 335 and 392 years old. With uncertainty ranges factored in, the oldest could have approached or exceeded four centuries, which is where the widely repeated 400-year figure comes from. An individual at the top of that range would have been born before many of the nations that now border its range even existed, and the work established the Greenland shark as the longest-lived vertebrate on record.

That comparison to the age of the United States is not just rhetorical flourish. A shark estimated at nearly 400 years old in the mid-2010s would have entered the world in the seventeenth century, generations before the American colonies declared independence in 1776. The same animal could still be swimming in Arctic waters, having outlasted empires, industrial revolutions, and dozens of human lifetimes.

A life lived in the slow lane

Extreme longevity in this species is tied to an extreme pace of living. Greenland sharks inhabit deep, near-freezing water where cold temperatures suppress metabolism, and they grow only about a centimeter or so per year. That crawling growth rate is the flip side of their long lives: reaching a body length of several meters simply takes centuries. Descriptions of the species by wildlife specialists consistently emphasize how this sluggish existence, played out in one of the harshest habitats on the planet, stretches every stage of the life cycle far beyond what faster-living animals experience.

The most consequential side effect is reproductive. If the study’s estimates are right, female Greenland sharks may not reach sexual maturity until they are around 150 years old. A predator that takes a century and a half just to begin breeding has almost no capacity to bounce back quickly from population losses, which is one reason scientists have flagged the species as vulnerable to bycatch and other pressures despite its remoteness.

Why the record still stands

Before the eye-lens work, the crown for longest-lived vertebrate was often given to the bowhead whale, thought to reach around 200 years, or to giant tortoises that can pass 150. The Greenland shark’s estimated ages roughly doubled the top of that range, and no other backboned animal has since produced comparable evidence to unseat it. The finding endures as a benchmark precisely because the method, dating a tissue formed in the embryo, sidesteps the guesswork that plagued earlier attempts to age soft-bodied deep-sea fish.

The estimates carry acknowledged uncertainty, and refining them will take more specimens and improved calibration. But the central conclusion has held up: a fish that most people have never heard of quietly outlives every other creature with a spine. For an animal that spends its centuries drifting through darkness far below the surface, the recognition marks one of the more surprising discoveries in modern zoology, and a reminder that some of the oldest living things on Earth are hiding in plain, cold water.

This article was researched and drafted with the assistance of AI and reviewed before publication.

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