American Oceans

Greenland Shark

Both experts and the general public find the Greenland shark to be a fascinating animal. It can reach a length of 7 meters and a weight of over 1,000 kilograms, making it one of the largest shark species now extant. Even without its distinctive qualities, it is a striking sight due to its size alone.

Greenland shark near the ocean ground, Somniosus microcephalus

The longevity of the Greenland shark is one of its most amazing characteristics. With some individuals living for almost 400 years, it is the longest-lived vertebrate in the entire animal kingdom.

This is twice as long as the giant tortoise, which is the longest-living land animal. The shark’s extraordinary longevity is still a mystery to scientists, but it is thought to be tied to both its slow metabolism and the frigid, nutrient-poor waters it lives in.

The Greenland shark is an enigmatic animal about which we still have much to understand, despite its astounding size and age. To learn more about this mysterious fish and its place in the ocean environment, scientists are still researching it.


The Greenland shark, also known as the “sleeper shark,” is a cold-water species that inhabits the North Atlantic and Arctic regions.

Greenland shark

It is one of the largest cartilaginous fishes, with females typically growing larger than males. These sharks can reach lengths of up to 7 meters (23 feet) and weigh over 1,000 kg (2,200 pounds) when fully grown.

Physical Characteristics

Greenland sharks have a unique appearance, with a short, rounded snout and small eyes. Their skin is dark gray or black and covered in tiny, tooth-like scales called dermal denticles. These denticles make their skin feel like sandpaper to the touch. The shark’s body is elongated and cylindrical, with two dorsal fins and a long caudal fin.

One of the most notable physical characteristics of the Greenland shark is its slow growth rate and long lifespan. These sharks are believed to live for up to 400 years, making them the world’s longest-living vertebrate. They also have a very slow metabolism, which allows them to survive in the cold waters of the North Atlantic.

The range of the Greenland shark is vast, with individuals being found throughout the North Atlantic and Arctic regions. They have been observed as far south as the Gulf of Maine and as far north as the Arctic Ocean. Despite their wide range, little is known about their migration patterns or behavior.


The Greenland Shark is a slow-moving species that typically swims at rates of less than 3 km per hour.

Greenland shark, Somniosus microcephalus

They are thought to prefer colder, deeper environments but may be found anywhere between the sea surface and depths of 2,200 meters. Very little is known about the everyday behavior of these creatures.

Diet and Prey

Greenland Sharks are known to be opportunistic feeders, which means they will eat almost anything they come across. They are known to scavenge on a variety of dead animals, including polar bears, seals, and reindeer. They are also known to prey on live animals such as fish, squid, and other sharks.

Reproduction and Life Cycle

Greenland Sharks have a slow growth rate and a long lifespan, with some individuals living for up to 400 years. The gestation period for Greenland Sharks is not well known, but it is believed to be around 2 years. Females give birth to an average of 10-12 pups, which are born at a length of around 35-50 cm.


The Greenland shark is a fascinating species with a unique ecology. In this section, we will explore its habitat and range, as well as its conservation status.

Habitat and Range

Greenland sharks are found in the deep waters of the North Atlantic Ocean, including the waters around Greenland. They are primarily found in waters deeper than 200 meters, but they have been known to venture into shallower waters as well. These sharks prefer colder waters, with temperatures ranging from -1.2°C to 10°C.

The Greenland shark’s range is vast, spanning from Canada in the west to Norway in the east. They have also been spotted in the waters around Iceland, the Faroe Islands, and the United Kingdom. These sharks are known to migrate long distances, with some individuals traveling up to 2,000 kilometers in a single year.

Conservation Status

The Greenland shark is currently listed as “Data Deficient” on the IUCN Red List of Threatened Species. This means that there is not enough information available to determine their conservation status. However, there are concerns about the impact of commercial fishing on their populations.

Greenland sharks are often caught as bycatch in commercial fishing nets, and their meat is considered a delicacy in some countries. Additionally, their slow growth rate and late maturity make them particularly vulnerable to overfishing. Carbon dating has revealed that some Greenland sharks can live for over 400 years, making them one of the longest-living vertebrates on the planet. If their populations continue to decline, there is a risk of extinction.

Cultural Significance

The Greenland shark has played an important role in the culture and mythology of the Inuit people. Additionally, the shark has been used as a food source in Iceland for centuries.

Inuit Legends

According to Inuit mythology, the Greenland shark is a powerful and mystical creature. The shark is believed to be the embodiment of the sea goddess Sedna and is thought to possess great spiritual power. The Inuit people believe that the shark’s flesh has a urine-like smell and that it acts as a helping spirit to shamans.


In Iceland, the Greenland shark is known as hákarl. Hákarl is a traditional Icelandic dish that is made from the shark’s flesh. The shark’s meat is toxic when fresh, so it must be buried in the ground for several months to allow it to ferment. After the fermentation process is complete, the meat is hung out to dry for several months.

Hákarl has a strong ammonia smell and a unique flavor that is not for everyone. It is typically served as a snack or appetizer and is often accompanied by a shot of Icelandic schnapps.

In recent years, hákarl has become a popular tourist attraction in Iceland, with many visitors eager to try the traditional dish. However, it is important to note that hákarl is not for everyone and should be consumed with caution.


The Greenland shark (Somniosus microcephalus) is a fascinating species with unique physiological traits that allow it to survive in the harsh Arctic environment. In this section, we will explore some of the key aspects of the Greenland shark’s physiology, including its metabolism, proteins, liver oil, and TMAO.

Metabolism and Proteins

The metabolism of Greenland sharks is relatively slow compared to other fish species, which allows them to conserve energy in the cold waters they inhabit. A recent study published in Nature found that the metabolic rate of Greenland sharks is about 1.3 times slower than what would be expected for a fish of its size. This slow metabolism is thought to be an adaptation to the low temperatures and limited food resources in the Arctic.

Greenland sharks also have unique proteins in their muscles that allow them to function in the cold waters. These proteins are known as “antifreeze proteins” and help prevent ice crystals from forming in the shark’s tissues. This adaptation allows the shark to maintain its muscle function even in sub-zero temperatures.

Liver Oil and TMAO

Greenland sharks are known for their large livers, which can account for up to 25% of their total body weight. The liver of the Greenland shark is rich in oil, which is used for buoyancy control and energy storage. In fact, the liver oil of Greenland sharks has been used by humans for centuries as a source of lamp oil and food.

However, the liver of the Greenland shark also contains high levels of trimethylamine oxide (TMAO), a compound that is toxic to humans. TMAO is produced by the shark’s liver as a way to counteract the effects of the high levels of urea in its bloodstream. Urea is produced by the shark’s metabolism and helps it to maintain buoyancy in the water. TMAO helps to prevent the buildup of urea in the shark’s tissues, but can be harmful to humans if ingested in large amounts.

Interesting Facts

Greenland sharks are fascinating creatures that inhabit the deep, cold waters of the Arctic Ocean and the western Caribbean. Here are some interesting facts about this unique shark species.

Longest-Living Vertebrates

Greenland sharks are known for having the longest known lifespan of any vertebrate species. According to radiocarbon dating, some individuals have lived for over 400 years, making them one of the longest-living animals on the planet. These slow-moving sharks reach sexual maturity at around 150 years of age, and females can carry their young for up to two years before giving birth.

Poisonous Meat

While Greenland sharks are not poisonous themselves, their meat can be toxic to humans. This is because the flesh contains high levels of trimethylamine oxide, which is converted to trimethylamine during decomposition. Trimethylamine is a compound that can cause symptoms such as nausea, vomiting, and even coma in humans if consumed in large quantities. As a result, Greenland sharks are not commonly eaten, although they are sometimes used as bait for other predatory fishes.

Despite their poisonous meat, Greenland sharks are known to be scavengers and will eat a variety of prey, including fishes, invertebrates, and even moose that have fallen into the water. Their teeth are designed for crushing rather than cutting, which allows them to feed on tough prey such as squid and gurry sharks.

Greenland sharks are also unique in that they have a slow metabolism and move at slow speeds, making them well-adapted to life in the deep, cold waters of the Arctic. They are also one of the few shark species that are blind, relying on their sense of smell and electroreception to locate prey.

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