The Greenland shark is a slow, cold-water giant that most people will never see, and yet it holds one of the most astonishing records in the animal kingdom: it is the longest-lived vertebrate known to science, with individuals estimated to survive for centuries. The math is dizzying — a large Greenland shark cruising the North Atlantic today may have been born before the founding of the United States, and possibly before the pilgrims landed.
That claim sounds like folklore, but it rests on a clever piece of forensic chemistry rather than legend. For a species that lives in near-freezing darkness and grows about a centimeter a year, ordinary methods of aging an animal simply do not work, and it took an unusual approach to reveal just how old these sharks can get.
Radiocarbon in the eye lens revealed the age
The breakthrough came from a 2016 study that dated the sharks using the one part of their body that never stops carrying a chemical timestamp: the eye. Researchers analyzed the lens nuclei of 28 female Greenland sharks caught as bycatch and applied radiocarbon dating, taking advantage of the fact that the center of the lens forms before birth and stays chemically unchanged for life. Published in the journal Science, the work used eye-lens radiocarbon to reveal centuries of longevity in the species, whose scientific name is Somniosus microcephalus.
The technique leaned on an accident of history. Atmospheric nuclear tests in the 1950s and 1960s released a pulse of carbon-14 that spread through the oceans and into the tissues of animals alive at the time, leaving a detectable marker. Sharks whose lens chemistry showed that bomb-pulse signal had to have been born around or after that era; those without it were older, and their ages could be estimated from the size-and-age relationship the study built.
An estimated lifespan measured in centuries
The results were staggering. The analysis, summarized in the study’s published record, put the sharks’ lifespan at a minimum of 272 years, with the largest specimen — a female measuring about 502 centimeters, or more than 16 feet — estimated at roughly 392 years. Because the method carries a wide margin of uncertainty of about 120 years, the true range for that animal stretches from roughly 272 to 512 years. Even at the conservative end, that makes the Greenland shark the longest-lived vertebrate ever documented, outstripping bowhead whales and long-lived fish like the rougheye rockfish.
The same work produced an equally remarkable finding about reproduction: female Greenland sharks appear not to reach sexual maturity until they are around 156 years old. An animal that spends its first century and a half simply growing toward adulthood is exceptionally vulnerable to population decline, because losses to bycatch or hunting cannot be replaced for generations.
Life in the cold and the dark
Everything about the Greenland shark’s biology points toward the slow lane. It lives in the frigid waters of the North Atlantic and Arctic, often at great depth, where temperatures hover near freezing and food is scarce. Its metabolism runs correspondingly slowly, and it moves at a famously sluggish pace — slow enough that seals it is known to eat may sometimes be taken while asleep. A profile of the species notes that this large, cold-adapted shark grows only about a centimeter per year, which is why reaching lengths beyond five meters implies such extreme age.
That combination of cold, depth and torpor is widely thought to underlie the longevity. Low temperatures and a slow metabolism reduce the cellular wear that accumulates over a lifetime, and researchers studying the species have looked to it as a natural model for how aging can be stretched across centuries rather than decades.
Eyes that keep working after a hundred years
The eye that made the aging study possible also raises its own puzzle. Many Greenland sharks host a parasite that attaches to the cornea and can leave the animal effectively blind, which long led to the assumption that vision mattered little to a creature hunting in the dark. But more recent research has complicated that picture. A 2025 study of the species’ visual system, published in Nature Communications, found that the sharks retain functional vision across extraordinary spans of time, suggesting the eye continues to serve a purpose even in an animal that may have been alive for hundreds of years.
Together, the findings reframe a shark long dismissed as a sluggish scavenger into one of the more scientifically valuable animals in the ocean. Its lens records history, its slow clock offers clues to the biology of aging, and its long march to maturity is a warning about how easily a centuries-old species could be pushed toward collapse. For an animal that may quietly outlast a dozen human generations, the Greenland shark has turned out to have a great deal to say about time.
This article was produced with AI assistance and reviewed by the Morning Overview editorial team.
More from Morning Overview
