A Greenland Shark Born in 1620 is Still Alive Four Centuries Later

Imagine a creature so ancient that it was already swimming through the icy waters of the North Atlantic when Galileo was peering through his telescope and Shakespeare was still crafting plays. A living being that has silently witnessed the rise and fall of empires, the birth of electricity, and the dawn of the digital age all without making a sound.

This is no legend, no mythical sea monster etched into old sailor maps. It’s the Greenland shark an elusive giant of the deep that holds the record for the longest-living vertebrate on Earth. One female, born around the year 1620, is still alive today, gliding slowly through the frigid darkness with the patience only centuries can teach.

How does a shark live for 400 years? What secrets does it hold beneath its thick skin and glacier-chilled blood? Scientists are only beginning to unravel the mystery one that challenges everything we thought we knew about aging, resilience, and time itself.

Understanding the Extraordinary Lifespan of the Greenland Shark

The Greenland shark’s remarkable longevity up to 400 years or more is not the result of a single evolutionary advantage, but rather a convergence of unique biological traits and environmental factors that allow this species to outlive virtually every other vertebrate on Earth.

At the heart of this longevity is an incredibly slow growth rate. Greenland sharks grow at just about 1 centimeter per year, a glacial pace that aligns with their overall sluggish life strategy. A typical adult can measure up to 5–7 meters in length and weigh over a ton, but it takes them centuries to get there. Most astonishingly, they don’t even reach sexual maturity until around 150 years of age, a record in the animal kingdom. This slow development mirrors an internal aging process that’s equally gradual.

Another crucial factor is their cold-water habitat. These sharks dwell in the deep, frigid waters of the North Atlantic and Arctic Oceans, where temperatures hover around -1.6°C (29°F). In such an environment, biological processes are naturally slowed, reducing the metabolic wear and tear that typically accelerates aging. Their heartbeat is slow around 10 beats per minute and they cruise through the deep at an unhurried pace of about 0.76 mph, earning them the nickname “sleeper sharks.”

Yet for decades, one major mystery remained: How could scientists be sure of their age? Most fish can be aged by counting growth rings in bones or scales, but Greenland sharks lack the calcified tissues needed for such methods. The breakthrough came when scientists discovered that the proteins in the core of their eye lenses remain unchanged from birth, essentially freezing a biological timestamp in place. Using radiocarbon dating a technique commonly used in archaeology researchers analyzed 28 sharks and found one female whose age was estimated between 272 and 512 years, with 400 years being the most likely.

Dr. Julius Nielsen, who led the 2016 study published in Science, expressed astonishment at the findings: “We had our expectations that we were dealing with an unusual animal, but… everyone doing this research was very surprised to learn the sharks were as old as they were.”

The discovery not only redefined what we know about vertebrate longevity, surpassing the previous record held by the 211-year-old bowhead whale, but also raised profound questions about aging, adaptation, and what life at the extremes can teach us. As scientists now examine the sharks’ genetic material, immune systems, and cardiac health, there’s growing curiosity about whether these cold-water giants may hold insights that extend far beyond the ocean.

How Harsh Environments May Help Sharks Cheat Time

If the Greenland shark’s near-immortality seems otherworldly, much of the explanation may lie in the world it inhabits one that is cold, dark, and largely untouched by human interference. In the bitter waters of the North Atlantic and Arctic Oceans, where temperatures can plunge to -1.6°C (29°F), this shark has evolved to not only survive but thrive under conditions that would debilitate most other marine life.

Scientists believe this extreme cold is a key player in the shark’s longevity. Cold environments naturally slow down biological processes, reducing cellular turnover, metabolic stress, and the accumulation of molecular damage over time. In other words, living in near-freezing temperatures may act as a biological brake on aging. As Dr. Julius Nielsen put it, the Greenland shark’s body is “built for patience and endurance,” and the cold amplifies that design.

This adaptation is evident in their lifestyle. Greenland sharks move at an average speed of just 0.3 meters per second less than one mile per hour making them among the slowest swimmers in the ocean. They conserve energy with every movement, minimizing metabolic strain. Their sluggish pace earned them the nickname “sleeper sharks”, but their occasional bursts of speed when attacking prey remind us they are still apex predators when needed.

Their circulatory system mirrors this slow rhythm. With a resting heart rate as low as 10 beats per minute, their internal organs operate with extreme efficiency. This isn’t merely a function of cold-blooded biology it’s an intricate evolutionary response to conserving energy in a habitat where resources are sparse and energy cannot be wasted.

Moreover, the deep-sea environment where they reside often at depths of 600 to 2,000 meters offers additional advantages. The absence of sunlight at these depths reduces exposure to ultraviolet radiation, a known accelerator of cellular damage and aging. The pressure is immense, but the environment is also relatively stable, with fewer predators and less environmental fluctuation. This consistency may allow the shark’s slow-growing body to avoid the kinds of stress that trigger aging processes in more dynamic ecosystems.

Still, these frigid, low-light ecosystems don’t come without cost. Greenland sharks often host copepod parasites on their eyes, which can impair or even block vision completely. Yet they manage to navigate and survive, relying on other senses, possibly even electromagnetic detection, to find food and orient themselves in the ocean.

Human Impacts and Conservation Challenges

Historically, Greenland sharks were hunted extensively for their oil-rich livers, which were once a valuable source of lubricant for machinery and lamp oil. This commercial exploitation reached its peak in the early 20th century, especially before World War II, when synthetic alternatives were not yet available. Tens of thousands of sharks were killed during this period, and though targeted hunting has declined, the ecological scars remain.

Today, the threat has shifted to accidental capture, known as bycatch. Greenland sharks are frequently entangled in fishing gear intended for other deep-sea species. Around 3,500 of these sharks are believed to be caught unintentionally each year a significant number for a species that reproduces slowly and doesn’t reach maturity until about 150 years of age. Most of the sharks observed today are considered “teenagers” in biological terms, not yet capable of contributing to the next generation.

Dr. Julius Nielsen, one of the leading researchers on Greenland sharks, noted the troubling implications: “When you evaluate the size distribution across the North Atlantic, it is quite rare to find sexually mature females or juveniles. That makes sense most of the older sharks were lost to historical fishing, and it will take a century or more for today’s young sharks to replace them.”

Adding to the difficulty is the mystery surrounding their reproduction. Scientists have yet to observe Greenland sharks mating or giving birth in the wild. It’s believed that they may carry up to 10 pups at a time, with gestation periods possibly lasting several years, but these are educated guesses at best. Without a clearer understanding of their reproductive biology, conservation planning becomes even more complex.

Efforts to protect Greenland sharks are growing but still lack global coordination. Experts recommend practical interventions such as using LED lights on deep-sea fishing nets to deter sharks, establishing protected marine zones, and restricting the use of gillnets in critical habitats. Marine conservationist Amanda Costello cautioned, “Any loss from fishing or accidental capture could take hundreds of years to fix. We have to protect them now if we want them to survive into the next centuries.”

Science, Mystery, and the Future

One of the most profound unknowns is how Greenland sharks reproduce. No one has ever witnessed them mating or giving birth in the wild. Based on limited data, scientists speculate that females may carry up to 10 pups at a time, and that gestation could last several years but without direct observation, these remain theories. This reproductive obscurity presents a major obstacle to conservation efforts, as it’s impossible to design effective protections without knowing when, where, or how often these sharks breed.

Their migration patterns and social behaviors are equally elusive. Greenland sharks are believed to inhabit a wide swath of the North Atlantic and Arctic Oceans, yet their movement through these vast and mostly inaccessible regions is difficult to monitor. Advances in deep-sea tracking technology and satellite telemetry may eventually yield answers, but for now, many aspects of their daily lives remain hidden in the deep.

Perhaps most intriguing is the potential for biomedical discovery. Scientists are now turning their attention to the Greenland shark’s genome, immune system, and heart function to understand what biological mechanisms allow them to age so slowly and resist age-related diseases. The eye lens dating technique that helped estimate their age also opened a new frontier in aging research offering a rare opportunity to study how long-term metabolic stability might influence longevity in other species, including humans.

There is also interest in whether certain adaptations such as the shark’s resistance to cellular degradation in extreme cold or its extremely efficient circulatory system could be applied to human health, longevity, or medicine. Early-stage research is exploring if insights from the shark’s biology could contribute to immune-boosting therapies or methods of slowing human aging, though such applications remain speculative.

Even in the realm of statistics, the Greenland shark continues to challenge conventions. The age range of the oldest known female shark was calculated using Bayesian statistics, a method devised by Reverend Thomas Bayes in the 18th century ironically, during the very century the shark itself was likely born. This poetic overlap serves as a reminder that while science has made remarkable strides, nature often keeps the upper hand when it comes to time.

As marine biologist Julius Nielsen said, “We are only beginning to understand these sharks.” And that truth may be the most compelling aspect of all: a creature so old, so enduring, and yet still so unknown. In an age where information seems boundless, the Greenland shark is a humbling testament to how much of our natural world remains undiscovered.

Guardians of Ancient Oceans

The Greenland shark is more than a biological marvel it is a living connection to a time when the world was vastly different. It began life in an ocean untouched by industrial fishing, centuries before electricity lit our cities or railroads crisscrossed continents. And yet, it continues to glide silently through the dark waters, unbothered by the passage of empires, inventions, and ideologies.

Its story is a reminder that longevity is not just about survival, but adaptation, patience, and balance. The Greenland shark doesn’t sprint through life it drifts deliberately, slowly accumulating the years with quiet endurance. In many ways, it embodies the opposite of our fast-paced, short-sighted approach to nature. It teaches us the value of slowness in a world obsessed with speed, and endurance in an era driven by urgency.

But this ancient endurance is not invincible. The threats Greenland sharks face today—overfishing, habitat disruption, and climate change are entirely human-made. And because of their biology, any damage we inflict may take centuries to undo, if it can be undone at all.

Protecting the Greenland shark is not just about saving one species. It’s about preserving a window into Earth’s distant past, a creature that holds secrets we’ve only begun to decode. It’s also a moral reckoning with how we treat life forms that can’t cry out or fight back, especially those that have endured for centuries without ever harming us.

As marine conservationist Amanda Costello wisely said, “This is not about the next five or ten years. It’s about saving a species that might still be here in 2425.”

In a time when the future of so many species feels uncertain, the Greenland shark gives us both urgency and hope. It reminds us that we are not the first to walk this Earth—and with care, we don’t have to be the last.