Researchers are uncovering strange details about one of the slowest-living predators on Earth.
It’s not just ancient trees or frozen bacteria that outlast generations. Somewhere in the pitch-black depths of the North Atlantic swims a shark so slow-growing it can live longer than the United States has existed. And it doesn’t just survive—it thrives in a world without sunlight, in icy waters that could stop most creatures cold. Here’s what scientists have uncovered so far, and why this shark has become one of the most mysterious animals in the ocean.
1. A single lifetime can span nearly half a millennium.
According to the Marine Research Institute in Iceland, Greenland sharks can live over 400 years, making them the longest-living vertebrates known. The oldest ever recorded was estimated at around 392 years old, and researchers believe that wasn’t even the maximum. Imagine a shark that was swimming when Shakespeare was alive, still cruising the same waters today. It doesn’t just live long—it outlives human civilizations, watching history pass without ever coming to the surface for a glimpse. The sheer timescale is so enormous that it redefines what “old” even means. And the ocean doesn’t exactly keep a scrapbook, so every decade of its life remains an unphotographed mystery.
2. Growth so slow, centuries pass before it matters.
At an average of less than one centimeter per year, this shark’s growth rate is glacial—literally slower than most glaciers move. Scientists discovered this by tagging individuals and returning years later to find they’d barely changed in size. The effect is surreal, as if time runs differently down there. In a way, it does, since metabolic processes slow dramatically in the near-freezing water. This steady, almost static existence means a 16-foot Greenland shark could easily be centuries old, hiding its true age beneath an unchanging, almost ancient-looking exterior. The idea of something moving through life that slowly, with no rush to reach any milestone, makes our own frantic timelines look absurd by comparison, as stated by research from the University of Copenhagen.
3. Parasites have claimed its eyes as prime real estate.
As discovered by the Arctic University of Norway, many Greenland sharks have a bizarre parasite attached to their eyes—a tiny crustacean called Ommatokoita elongata. It latches on and clouds their vision, sometimes making them nearly blind. Oddly, this doesn’t seem to be a huge problem for them. Living in near-total darkness, sight isn’t their top priority. They rely on an extraordinary sense of smell and the ability to detect vibrations to hunt or scavenge. Still, it’s hard not to imagine what it’s like to cruise through the depths for centuries with a permanent, uninvited roommate attached to your eyeball. And the fact that they don’t seem to care makes them even more unfathomably alien.
4. The menu is mostly decades-old leftovers.
A Greenland shark isn’t racing after schools of fish—it’s taking its sweet time, often eating carrion that’s drifted down into the depths. We’re talking whale carcasses, dead seals, and whatever other ocean leftovers happen to sink its way. This slow, opportunistic feeding style fits perfectly with its low-energy lifestyle. It doesn’t waste calories chasing food when the ocean eventually brings dinner to its door. The result is a diet that’s as unpredictable as it is unappetizing to us, yet it fuels the shark for centuries of life.
5. One bite of fresh meat could send you stumbling.
While you technically can eat Greenland shark, you’d regret it unless it’s been fermented for months. The flesh contains high levels of trimethylamine oxide (TMAO), which can cause extreme intoxication—think dizzy, disoriented, and barely able to stand. This is why in Iceland, it’s processed into hákarl, a traditional dish that involves burying and drying it until the toxins are neutralized. Fresh, it’s nature’s version of a dangerous cocktail, one that’s been making curious humans sick for centuries.
6. Speed is laughably low, but survival is sky-high.
Even when fully grown, Greenland sharks cruise at a leisurely 0.7 miles per hour. That’s slower than most people walk. Yet somehow, this doesn’t seem to hurt its survival odds. In the depths, speed isn’t everything—stealth and endurance matter more. This unhurried movement means it can travel huge distances over decades without exhausting itself, quietly patrolling territory while other predators burn out in a fraction of its lifetime.
7. Sightings have popped up far beyond its icy home.
Though most are found in Arctic and North Atlantic waters, there have been reports of Greenland sharks turning up as far south as the Gulf of Mexico. This range suggests they’re far more adaptable than previously thought, able to navigate drastically different temperatures and depths. It also fuels theories that they may be quietly inhabiting areas we don’t yet monitor. In a world where humans think we’ve mapped everything, this is a reminder that the ocean keeps most of its secrets well out of reach.
8. Their mating habits remain one of the ocean’s biggest mysteries.
No one has ever documented Greenland sharks mating in the wild, and scientists aren’t even sure where it happens. The females don’t reach sexual maturity until they’re around 150 years old, which means any courtship is staggeringly rare. Theories suggest deep, remote areas far from human eyes, possibly even under ice sheets, could be the setting. This lack of evidence keeps researchers guessing, and every encounter with the species feels like brushing against a centuries-old riddle with missing pages.
9. They can vanish into depths that seem unreachable.
While they’ve been caught at shallower depths, Greenland sharks are known to roam down to 7,200 feet below the surface. At that depth, the pressure is intense, the temperature barely above freezing, and sunlight doesn’t exist. For humans, this is an utterly inaccessible environment without high-tech submersibles. Yet for these sharks, it’s just another quiet corridor of their vast home range, a place where no predator follows and where they can disappear for decades at a time.
10. Even their deaths leave behind a lasting impact.
When a Greenland shark finally dies—likely after centuries—it doesn’t just vanish into the darkness unnoticed. Its body sinks to the seafloor, becoming a feast for a community of deep-sea creatures. Hagfish, crabs, and countless unseen scavengers will strip it clean over months, turning it into a temporary oasis of energy in an otherwise food-scarce environment. In life, it shaped the ecosystem slowly and quietly. In death, it fuels the deep just as silently, completing a cycle that can take half a millennium to play out.