The Greenland Shark is also known as
Sleeper shark, Ground shark, Gray shark and Gurry shark.
Scientific name.........Somniosus Microcephalus
Greenland sharks are large, slow-swimming sharks that have
glow-in-the-dark eyes. They have a short snout, thin lips, and small
fins, a caudal fin with a well-developed lower lobe, and two small,
spineless dorsal fins; they lack an anal fin. This shark has a
bioluminescent ( glowing ) copepods attached to the Greenland
shark's corneas. This may attract curious prey to the shark's head.
The gill openings are very small in comparison to its size and are
located low on the sides of the shark's head.
Greenland sharks average in size from 8 to 14 feet with females
being the larger sex. This shark reaches a maximum length of about
21 feet; although it may grow to 24 feet, and weighing 1,020. Growth
of this shark is very slow due to the cold temperatures of its
climate. There are no known predators of the Greenland shark, which
is most likely due to its massive size.
The teeth of the Greenland shark's upper jaw are long and pointed,
very different from those of its lower jaw, which are strongly
oblique, sharp, and close set. These teeth allow it to gouge large
chunks of flesh from dead cetaceans, and probably to remove the
heads of seals and sea lions rapidly before dining on the carcasses.
The Greenland shark varies between a black, brown, and gray color.
Although this shark is usually uniform in color, it may often be
marked with dark lines or white spots along its back and sides.
This sharks diet consists of a large variety of ocean dwellers such
as other small sharks, skates, eels, herring, capelin, char, various
gadoids, redfish, sculpins, lumpfish, wolfish, and flounders. Marine
mammals, such as seals and porpoises, are often taken by Greenland
sharks despite it being characterized as a very sluggish creature. A
few Greenland shark specimens have even been found to contain an
entire reindeer and parts of a horse. The shark is also known to
feed off carion and is attracted to ill-smelling meat. This sluggish
shark can capture such wily and fast-moving prey may be because of
small copepods that attach themselves to the corneas of the shark's
eyes. Brightly luminescent, these copepods are thought to attract
curious and hungry prey, which soon end up in the shark's cavernous
They often congregate in large numbers around fishing operations.
They are found in North Atlantic and Arctic Ocean occasionally to
Portugal. This gigantic dogfish shark is the only polar shark of the
Atlantic Ocean. It lives in deep water to 1,800 feet in continental
and insular shelves and upper slopes in water temperatures of 36-45
F (2 to 7 C). Inshore in Arctic winter ( from intertidal and surface
in shallow bays and river mouths ), retreats to 590 to 1,804 feet
when temperature rises. May move into shallower water in spring and
summer in north Atlantic.
Little is known about the Greenland shark's reproductive behaviour.
It was recently discovered to be ovoviviparous. The female carries a
large number of soft-shelled eggs eventually giving birth to
full-term embryos. Some eggs have been reported to be as large as
goose eggs. One 16 feet specimen was reported to have contained ten
,15 inches long full-term embryos in one of its uteri.
This species is a very sluggish slow-swimming shark, and provides
little resistance when captured.
Potentially harmful. The lack of recorded attacks may only be due
to the shark's habitat, which is much too cold to be populated by
common swimmers, therefore, significantly reducing the chance of an
attack on a human.
This shark has been classified as Somniosus microcephalus by Bloch
and Schneider ( 1801 ). Roughly translated, Somniosus pertains to
"sleep" which describes the shark's sluggish movement, and
microcephalus literally means "small head".
Inuit's often catch this fish by luring it to a hole chopped in the
ice and either harpooning it or simply dragging it out of the water
by hand. Its flesh, however, unless properly prepared is highly
toxic and causes symptoms similar to those caused by too much
alcohol. The Greenland shark is poisonous if eaten fresh, it is
edible when the meat has been dried. The flesh of the shark contains
high concentrations of urea and trimthylamine oxide, which is said
to intoxicating inducing an alcoholic affect.
Because this species inhabits very deep waters of the ocean, it is
almost completely dark, except for the light made by other animals.
Pressure can be a thousand times that at the surface. Adaptation at
such depths requires the ability to find and capture food, to avoid
being eaten, and to find a mate--in the dark.
Eskimos use the dried skin of the shark as leather for making boots
and the lower dental bands of the shark as knives primarily for
cutting hair or hunting.