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
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.