Greenland Shark

Greenland SharkThe Greenland Shark (Somniosus microcephalus), also called the sleeper shark and gurry shark, is one of the few sharks found in polar waters year-round. It’s one of the most interesting and still somewhat of a mystery for biologists. It has been referred to as other classifications since approximately 1758 but was finally classified as Somniosus microcephalus by Bloch and Schneider (1801).

It’s one of the largest sharks in the world and rivals the Great White in size although not as aggressive. Because it can grow to over 21 feet (6.5 meters) in length and weigh up to 2000 lbs. (900 kilos), the Greenland Shark is the largest Arctic fish. The female grows larger than the male. This shark is an extremely slow growing animal. Tagging studies have suggested that some of the adults may grow at a rate of only 1 cm (0.4 inches) per year.

Noted for its slow, deliberate movements, the Greenland Shark is believed to lure its prey close by taking advantage of bioluminescent parasites that live in its eyes. These glowing eyes may well be the shark's most striking feature. There are no known natural predators of the mature Greenland shark, which is most likely due to its massive size.

It lives in very deep waters of the North Atlantic Ocean at depths down to 1,800 feet (550 m) in very cold water (36 to 45°F=2 to 7°C). Its territory is along Greenland's coast and throughout the fjord systems, but they can range throughout the Arctic Ocean and as far south as the Gulf of St. Lawrence or the Gulf of Maine.

It is characterized by its large, heavy-set body which gives it a sluggish appearance and movement. It has a short, rounded snout, thin lips, and very small eyes. The dorsal and pectoral fins are very small, and it lacks spines in its dorsal fins.

The Greenland shark varies between a black, brown, and grey color. Although it is usually uniform in color, it may often be marked with dark lines or white spots along its back and sides.

It consumes capelin, char, halibut, herring, lumpfish and salmon among other fishes. It also feeds upon marine mammals such as seals, sea lions and cetaceans.

It is ovoviviparous and can have litters of up to 10 pups. The young are born at a size of 38 cm (15 in). It is unclear at what size males and females become mature. One female 285 cm long which was examined in Nova Scotia was immature.