The Greenland shark (scientific name: Somniosus microcephalus) is known for its slow movements and resides farther north than any other shark. They are the closest relatives of the Pacific shark. Greenland shark meat contains a neurotoxin called trimethylamine oxide. This shark is as ferocious as the great white shark.
The Greenland shark lives in North Atlantic around Greenland and Iceland. They swim in cold waters and live mainly on the continental shelf, except for some estuaries and shallow bays during the winter months.
In August 2002, an article was published in the world-renowned journal "Science," which mentioned a new scientific discovery: the lifespan of the longest-lived vertebrate known on earth may reach 400 years old, and 156 years old are counted. In their adulthood, the animal is called the Greenland shark. In the following post, you will learn more interesting facts about the Greenland shark.
Greenland Shark General Description
The Greenland shark is a massive species with a short, rounded snout, small eyes, and small dorsal and pectoral fins. Teeth 48-52 on the upper jaw are very fine and pointed without serrations. These upper jaw teeth act as anchors, while the lower jaw continues to cut chunks of food from prey for a quick and easy meal. Body color ranges from light cream to dark brown and is generally uniform in color, although whitish spots or dull black streaks are sometimes seen on its back.
The Greenland shark is one of the largest cartilaginous fishes. It can reach a length of 7 meters (23 feet) and a weight of 1,400 kg (3,100 lbs) when fully grown, but most are between 2 and 4 meters (6.5 and 13 feet) and weigh 700–1000 kg (2,200 lbs). Men are usually smaller than women. Females are thought to reach sexual maturity when they surpass the 4-meter (13-feet) mark in length, which takes approximately 150 years to achieve. However, people know little about how the species reproduces.
The shark migrates near shore in search of warmer waters in the north. It is usually spotted near the surface during the winter and retreats to depths of 591-1,804 feet (180 to 550 m) during the summer. In southern waters, the shark is found near continental shelves and slopes and is found at a depth of about 3,937 feet (1,200 m).
Although The Greenland shark is the slowest swimmer, it is a top predator. They feed on seabirds, squid, crustaceans, mollusks, and various carrion and offal. The Greenland sharks are also known as "crocodiles of the ocean" because they also eat marine mammals. Parts of reindeer, horses, and polar bears have even been found in the belly of some Greenland sharks. The Inuit used to hunt the Greenland shark for its razor-sharp teeth to make knives and cod liver oil to make oil lamps.
Greenland sharks are the longest-lived vertebrates on Earth, with a lifespan of up to 400 years, scientists from international scientific institutions reported in the journal Science. The animals grow very slowly, only about 1 cm per year, an important factor in their longevity. Greenland sharks are deep-sea sharks that live in cold waters of 1-12 degrees Celsius. Cold water can help these animals slow down growth and biochemical activity, extending their lifespan.
Greenland shark meat contains a neurotoxin called trimethylamine oxide(TMAO), which can cause symptoms in humans similar to severe inebriation and can even be incapacitating to sled dogs. TMAO helps the fish stabilize their enzymes and structural proteins against the debilitating effects of severe cold and high water pressure. Nonetheless, Greenland shark meat can be prepared in a fermentation process that removes the TMAO, resulting in a much-enjoyed national dish of Iceland.
Although the global Greenland shark population size is unknown, the development of fisheries in Norway, Iceland, Greenland, etc., has a significant impact on the population of this species. In the 1970s, the government adopted a fisheries subsidy policy to reduce the fishing of Greenland sharks. The decline could be much higher if the sharks have longer life spans and thus take longer to reach reproductive age and produce more sharks. Climate change is also hurting the species.