Updated: Oct 21, 2022
The Greenland shark (Somniosus microcephalus), also known as the Grey shark, Gurry shark or Ealussuaq, has gotten a lot of publicity lately. This is because recently a Greenland shark was found that was estimated to be about 400 years old! That is 200 years older than their average lifespan and it makes the Greenland shark the longest living vertebrate on earth! Moreover Greenland sharks are incredibly large; they can grow up to about 6.5 meters and they weigh about 900 kilos. These subarctic giants move slowly through the cold deep waters of the North Atlantic. The flesh of Greenland sharks holds high concentrations of TMAO (Trimethylamine Oxide) which causes the flesh to be extremely toxic. Their flesh is so toxic that it could kill a human if consumed.
Anatomy and appearance of the Greenland shark
Greenland sharks are one of the largest existing sharks. They can grow up to about 6.5 meters, however the average Greenland shark is about 5 meters in length. In addition, Greenland sharks are probably the slowest sharks and are therefore also known as sleeper sharks. Their average pace is 0.3 meters per second. However, they are capable of increasing their speed temporarily. The colours of adult Greenland sharks vary from slate grey, purplish grey, violet, brown to black. Greenland sharks have a short round snout and, in comparison with their length, they have extremely small dorsal and pectoral fins. The eyes of Greenland sharks are rather unique because of their small size. Moreover, most Greenland sharks are (partly) blind because of the Copepod (Ommatokoita elongata) parasite. These parasites attach themselves to the cornea of the eyes of the sharks. Some researchers believe that that these parasites are bioluminescent, however this has never been proven. Anyway Greenland sharks survive easily without their sight because they use their other senses to detect prey.
Habitat of the Greenland shark
The Greenland shark lives in the cold waters of the North Atlantic Ocean and the Artic Ocean. The water temperature that these sharks live in often varies from -1.6 to 10 degrees Celsius. Greenland sharks are the only known shark species that constantly live in these cold environments. These sharks can be found near the surface as well as extreme depths to about 2.200 meters. Generally Greenland sharks can be found in these extreme ocean depths during the summer months and closer to the surface during the winter months.
Source: By Chris_huh - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2828227
The diet of a Greenland shark is quite extensive, they will eat almost anything that crosses their path. Greenland sharks are primarily scavengers and fish eaters. However they also eat large sea mammals like seals. In addition Greenland sharks are known to ambush large animals that walk too close to the edge of the ice. For example the remains of polar bears, horses, moose and reindeers have been found in the stomachs of Greenland sharks.