The 400-Year-Old Shark: Earth's Oldest Living Vertebrate

Elle
Aug 13
8 min read

In the frigid, dark waters of the Arctic and North Atlantic oceans swims a creature that has witnessed centuries of human history unfold above the waves. The Greenland shark, a massive predator that can grow up to 24 feet in length, holds the remarkable distinction of being the longest-living vertebrate on Earth. Some of these ancient giants swimming in our oceans today were alive when the Mayflower crossed the Atlantic, when Shakespeare was writing his plays, and when the first permanent English settlement was established in America.

A Record-Breaking Discovery

In 2016, a groundbreaking study published in the journal Science shattered our understanding of vertebrate longevity. The oldest living Greenland shark in this study was estimated at 392 years old, but there are likely older Greenland sharks swimming around today. At nearly 400 years old, the oldest-known living vertebrate crossed the oceans at the same time as the Mayflower.

This discovery didn't happen by accident. It was the result of years of dedicated research by marine biologists, led by Julius Nielsen and his team at the University of Copenhagen. Marine biologists at the University of Copenhagen have deployed an epoch-making method to unveil one of the greatest mysteries surrounding this enigmatic shark and have come to an amazing revelation: with a life expectancy of at least 272 years, the Greenland shark has the longest life expectancy of all vertebrate animals known to science.

The Challenge of Aging a Shark

Determining the age of a Greenland shark presents unique challenges that don't exist with other marine animals. Unlike many fish species, sharks don't have hard structures like ear bones (otoliths) that form annual growth rings. Traditional aging methods don't work on these ancient predators.

The Greenland shark's slow growth rate and massive size provided the first clues to their extraordinary longevity. Greenland sharks have the longest lifespan of any known vertebrate, estimated to be between 250 and 500 years. They are among the largest extant shark species, reaching a maximum confirmed length of over 20 feet. Scientists estimate the Greenland shark lives at least 250 years. They may live over 500 years.

The Breakthrough: Eye Lens Dating

The key to unlocking the Greenland shark's age lay in an unexpected place: their eyes. Steffensen and his graduate student Julius Nielsen spent several years collecting dead Greenland sharks, most of them accidentally ensnared in trawling nets used to catch other types of fish. After that, they employed an unusual technique: They looked for high amounts of carbon-14, a heavy isotope left behind by nuclear bomb testing in the mid-1950s.

Using a method called radiocarbon dating, the scientists measured amounts of carbon-14 (a slightly radioactive form of carbon that is present in all living things) in each of the shark's eyes that they sampled between 2011 and 2013.

The brilliance of this method lies in the unique properties of the eye lens tissue. Unlike other parts of the body that continuously regenerate and replace cells throughout an animal's lifetime, the center of an eye lens is formed during embryonic development and remains unchanged for the entire life of the organism. This means the carbon-14 signature in the lens nucleus reflects the atmospheric conditions at the time the shark was born.

The Nuclear Age as a Dating Tool

Along the recent historical timeline are key reference points for assigning dates, like the dropping of the atomic bombs and an increase in nuclear testing after World War II. The presence of a "bomb spike", or a significant increase in carbon-14, meant the shark was born before the 1960s.

Extra carbon from the resulting "bomb pulse" had infiltrated ocean ecosystems by the early 1960s, meaning that inert body parts formed during this time, in particular eye lens tissue, would contain elevated levels of carbon-14. Sharks born after the nuclear testing era would show this distinctive chemical signature, while older sharks would not.

This nuclear fingerprint provided scientists with a reliable method to distinguish between sharks born before and after the 1960s. For sharks that showed no evidence of the bomb pulse, researchers could then use standard radiocarbon dating techniques to estimate their birth dates, working backward from known carbon-14 decay rates.

The Remarkable Research Results

Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks revealed ages that astounded the scientific community. The largest shark in the study, measuring over 16 feet long, was estimated to be around 392 years old, with a margin of error that could place her age anywhere from 272 to 512 years.

Radiocarbon dating methods determined the age of a 16.5-foot female fish discovered swimming in the Arctic, making her potentially the oldest vertebrate ever recorded. Scientists found a 400-year-old Greenland shark likely born around 1620, making the sharks now the longest-living vertebrates known on Earth.

This means that the oldest sharks alive today began their lives during the early 1600s, when:

The Pilgrims were establishing Plymouth Colony
Galileo was making his astronomical discoveries
The Thirty Years' War was raging in Europe
Shakespeare had recently completed many of his greatest works

Life in the Slow Lane

Their incredibly slow lifestyle matches the extraordinary longevity of Greenland sharks. These giants of the deep live life at a pace that seems almost meditative compared to other marine predators. They grow approximately one centimeter per year, meaning a 20-foot shark has been slowly, steadily growing for centuries.

Greenland sharks can live to be 400 years old and only become sexually mature at 150, raising conservation concerns. This extended juvenile period means that Greenland sharks don't begin reproducing until they've survived for more than a century and a half.

A Cold-Water Giant

Greenland sharks, living in the cold, deep waters of the Arctic and North Atlantic Oceans, are one of the largest sharks in the world and can grow up to seven meters in length. Their massive size and slow metabolism are perfectly adapted to life in some of the ocean's most challenging environments.

This denizen of the frigid deep not only lives a crazy long life, but it can also grow up to 24 feet in length, and eating its flesh can make humans "shark drunk." The flesh contains high levels of trimethylamine oxide, which breaks down into a compound similar to alcohol when consumed, causing intoxication in humans, a fact known to indigenous Arctic peoples for generations.

The Mystery of Extreme Longevity

What allows Greenland sharks to live for centuries while most vertebrates live for decades? Scientists believe several factors contribute to their remarkable longevity:

Cold Water Metabolism: The frigid Arctic waters where these sharks live significantly slow their metabolic processes. Cold temperatures reduce the rate of cellular damage and metabolic wear and tear that typically accumulates over time.

Slow Growth Rate: Their extremely slow growth rate may contribute to longevity by minimizing cellular stress and reducing the risk of cancer-causing genetic mutations that can accumulate with rapid cell division.

Deep-Sea Environment: Living in the stable, low-stress environment of the deep ocean, away from temperature fluctuations, UV radiation, and many predators, may contribute to their extended lifespan.

Efficient Cellular Repair: These sharks may have evolved superior DNA repair mechanisms and antioxidant systems that help prevent the cellular damage typically associated with aging.

Conservation Implications

The discovery of the Greenland shark's extreme longevity has profound implications for conservation efforts. Greenland sharks can live to be 400 years old and only become sexually mature at 150, raising conservation concerns.

Their incredibly slow reproductive cycle means that Greenland shark populations are extremely vulnerable to overfishing and environmental changes. A single female might not begin reproducing until she's older than the United States as a nation, and the loss of mature breeding individuals could take centuries to replace naturally.

Currently, Greenland sharks are not heavily targeted by commercial fisheries, but they are often caught as bycatch in Arctic fishing operations. Climate change poses another threat, as warming Arctic waters could disrupt their deep-cold habitat and the ecosystems they depend on for food.

What These Ancient Sharks Have Witnessed

To put their longevity in historical perspective, consider what the oldest Greenland sharks have lived through:

1620s Birth Era:

The Mayflower voyage and Plymouth Colony establishment
The height of the Little Ice Age
The beginning of European colonization of the Americas

Throughout Their Lives:

The entire Age of Sail
The Industrial Revolution
Two World Wars
The invention of electricity, automobiles, airplanes, and the internet
The exploration of space
The development of modern medicine and technology

These sharks have been silent witnesses to four centuries of human progress, swimming through waters that have seen whaling ships, naval battles, and modern shipping lanes.

Ongoing Research and Future Discoveries

Dr Julius Nielsen, who has studied these mysterious creatures for many years, was part of the first team to estimate their extraordinary lifespan and explains exactly how they did it. His research continues to uncover new aspects of Greenland shark biology and behavior.

While the more than 5-meter-long Greenland shark is one of the world's largest sharks, it is also one of the least understood animals on our planet. Scientists are working to learn more about their:

Reproductive behavior and cycles
Migration patterns and habitat preferences
Diet and role in Arctic ecosystems
Population numbers and distribution
Response to climate change

The Search for Even Older Sharks

The oldest living Greenland shark in this study was estimated at 392 years old, but there are likely older Greenland sharks swimming around today. The research published in 2016 examined only 28 sharks, and given the species' wide distribution and the margin of error in dating techniques, even older individuals may exist in the deep Arctic waters.

Some researchers speculate that the oldest Greenland sharks could potentially be over 500 years old, which would make them contemporary with the early voyages of Christopher Columbus and the height of the Renaissance. The search for these ancient giants continues as scientists work better to understand the full extent of their remarkable longevity.

Lessons from the Deep

The Greenland shark's extraordinary lifespan offers valuable insights for aging research and longevity studies. Scientists are investigating the genetic and physiological mechanisms that allow these sharks to live for centuries, hoping to understand:

How they avoid cancer despite their large size and long lifespan
What cellular repair mechanisms prevent age-related deterioration
How their immune systems remain functional for centuries
Whether their longevity secrets could inform human health research

A Living Link to History

The oldest Greenland sharks are living links to centuries of Earth's history. Swimming in the same waters their ancestors have inhabited for millions of years, these ancient predators carry in their bodies the chemical signatures of bygone eras and the genetic wisdom of countless generations.

Now, scientists have discovered that Greenland sharks can live for hundreds of years, making them the world's longest living vertebrates. This discovery has fundamentally changed our understanding of vertebrate longevity and opened new avenues for research into the mechanisms of aging and longevity.

Guardians of Deep Time

The Greenland shark stands as a testament to the remarkable diversity of life strategies that evolution has produced. While most animals live fast and reproduce quickly, these giants have chosen a path measured in centuries.

As we face an era of rapid environmental change, the Greenland shark reminds us that some of nature's most remarkable achievements unfold over timeframes that dwarf human experience. These ancient mariners have survived ice ages, solar storms, and countless natural disasters by living slowly, growing steadily, and adapting to one of Earth's most challenging environments.

The 400-year-old shark swimming in today's Arctic waters has witnessed more history than any other animal on Earth. She represents a living connection to our planet's past and, if we protect her habitat and species, will continue to be a guardian of the deep for generations of humans yet to come. In a world of rapid change, the Greenland shark stands as a monument to the power of patience and the extraordinary potential for longevity that exists in the natural world.