What Is Greenland Shark? — The Full Story Explained

Defining the Greenland Shark

The Greenland shark, scientifically known as Somniosus microcephalus, is a massive deep-water predator primarily found in the cold waters of the North Atlantic and Arctic Oceans. Often referred to as the "sleeper shark" due to its sluggish movements and perceived lethargy, this species is one of the largest cartilaginous fish in existence. While its name suggests a limited range, researchers have documented these sharks as far south as the Caribbean and even the Gulf of Mexico, typically at extreme depths where the water remains near freezing.

Physically, the Greenland shark is distinct from the more famous Great White. It possesses a thick, cylindrical body that can reach lengths of up to 23 feet (7 meters), though most individuals are smaller. Its skin is typically dark gray, brown, or black, often appearing mottled. Unlike many other shark species, the Greenland shark lacks an anal fin and has relatively small dorsal fins. Its snout is short and rounded, housing rows of specialized teeth designed for gripping and cutting through a wide variety of prey.

Record-Breaking Lifespan and Age

Perhaps the most fascinating characteristic of the Greenland shark is its longevity. As of 2026, it remains the longest-living vertebrate on Earth. Scientific studies utilizing radiocarbon dating on the lenses of their eyes have revealed that these sharks can live for at least 272 years. Some estimates suggest they may reach ages of 400 to 500 years. This means there are individuals swimming in the Arctic today that were born before the industrial revolution or even during the era of early global exploration.

This extreme lifespan is attributed to an incredibly slow metabolism and the cold environment in which they live. They grow at a rate of only about one centimeter per year, and females are believed to reach sexual maturity only after they are 150 years old. Their biological processes are so slow that they appear to defy the typical aging patterns seen in other mammals and fish. Recent research into their "super DNA repair" kits suggests they have evolved highly efficient mechanisms to maintain cellular health over centuries.

Habitat and Arctic Survival

The Greenland shark is the only shark species known to tolerate the frigid conditions of the Arctic year-round. They are master divers, capable of reaching depths of over 7,000 feet (2,100 meters). They prefer water temperatures ranging from 1 to 12°C. In the winter, they may be found near the surface, but as the seasons warm, they retreat to the deeper, colder layers of the water column to maintain their preferred body temperature.

Survival in such an environment requires unique adaptations. Their tissues contain high concentrations of trimethylamine N-oxide (TMAO) and urea, which act as anti-freeze, preventing ice crystals from forming in their blood and cells. However, these compounds make their meat toxic to humans and other animals unless it is specifically treated through a long process of fermentation or drying.

Diet and Hunting Habits

Despite their slow movement, Greenland sharks are top predators with a diverse diet. They are not picky eaters and will consume almost anything they encounter in the deep. Their diet includes a variety of fish, such as eels, skates, and smaller sharks, as well as marine mammals like seals. There have even been instances where remains of terrestrial animals, such as reindeer and horses, were found in their stomachs, likely scavenged after the animals drowned or fell through the ice.

Because they move so slowly, it was long a mystery how they caught fast-moving prey like seals. It is now believed that they may ambush seals while they are sleeping underwater or use their stealth to approach prey undetected in the dark, murky depths. They are also significant scavengers, playing a crucial role in the deep-sea ecosystem by consuming carcasses that sink to the ocean floor.

Vision and Parasitic Relationships

A common feature of the Greenland shark is its seemingly poor vision. Many individuals are found with a specific parasitic copepod, Ommatokoita elongata, attached to their corneas. These parasites feed on the eye tissue, often causing partial blindness. For a long time, it was assumed that these sharks were effectively blind and relied entirely on their sense of smell and electroreception to find food.

However, recent studies in 2025 and early 2026 have challenged this "blind shark" narrative. While the parasites do cause damage, researchers have found that the sharks still possess functional visual systems and may even use the bioluminescence of the parasites to attract curious prey. Their DNA contains specific genes, such as ERCC1 and ERCC4, which help repair damage caused by aging and environmental stress, potentially preserving some level of sight even in extreme old age.

Comparison of Arctic Predators

To better understand the Greenland shark's place in the marine hierarchy, it is helpful to compare it with other large sharks found in similar or adjacent regions.

Feature	Greenland Shark	Great White Shark	Pacific Sleeper Shark
Max Lifespan	272–500 years	70 years	Unknown (likely long)
Max Length	Up to 23 feet	Up to 20 feet	Up to 14 feet
Water Temp	1°C to 12°C	12°C to 24°C	0°C to 15°C
Primary Habitat	Arctic / North Atlantic	Temperate / Subtropical	North Pacific / Arctic
Metabolism	Extremely Slow	Fast (Endothermic)	Slow

Conservation and Human Impact

The Greenland shark is currently classified as "Vulnerable" by the International Union for Conservation of Nature (IUCN). Historically, they were hunted for their liver oil, which was used as a lubricant and fuel. While large-scale commercial fishing for the species has largely ceased, they are still frequently caught as bycatch in deep-sea trawling operations targeting other fish like Greenland halibut.

Because they grow and reproduce so slowly, their populations are extremely sensitive to overfishing. If a large number of breeding-age adults are removed from the population, it could take centuries for the species to recover. Current conservation efforts focus on monitoring their movements using acoustic tags and reducing bycatch through improved fishing gear technology. Interestingly, while these sharks are not typically part of the financial markets, those interested in the broader "blue economy" or environmental conservation tokens can find related assets on platforms like WEEX. For those looking to diversify their portfolios into emerging sectors, you can visit the WEEX registration page to explore various trading options.

Interaction With Humans

Interactions between Greenland sharks and humans are incredibly rare due to the shark's preference for deep, cold water. There is only one historical report from the mid-19th century of a Greenland shark potentially attacking a human, but this has never been modernly verified. They are generally considered non-aggressive toward divers, often appearing indifferent to their presence.

The primary "interaction" humans have with this shark today is through scientific research and the traditional Icelandic dish known as Hákarl. To make Hákarl, the poisonous meat is buried in gravelly sand for several weeks to ferment, then hung to dry for several months. This process neutralizes the toxins, though the resulting meat has a very strong ammonia smell and taste that is an acquired preference even for locals.

Future Research Directions

As of February 2026, the scientific community is focused on unlocking the genetic secrets of the Greenland shark's longevity. By sequencing their entire genome, researchers hope to identify the specific proteins responsible for their "super DNA repair" capabilities. This research has implications far beyond marine biology, potentially offering insights into human aging and the prevention of age-related diseases.

Furthermore, climate change poses a significant threat to their habitat. As Arctic ice melts and water temperatures rise, the deep-sea environment is changing rapidly. Understanding how these ancient giants adapt to a warming ocean is a top priority for marine biologists. New non-invasive monitoring methods, such as environmental DNA (eDNA) sampling and deep-sea acoustic arrays, are providing more data than ever before, helping us piece together the life history of this enigmatic "living fossil."