Greenland shark
| Greenland shark | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Squaliformes |
| Family: | Somniosidae |
| Genus: | Somniosus |
| Species: | S. microcephalus |
| Binomial name | |
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Somniosus microcephalus (Bloch & J. G. Schneider, 1801) |
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| Range of the Greenland shark | |
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The Greenland shark (Somniosus microcephalus), also known as the gurry shark, or grey shark, or by the Inuit name eqalussuaq, is a large shark of the family Somniosidae ("sleeper sharks"), closely related to the Pacific and southern sleeper sharks. The distribution of this species is mostly restricted to the waters of the North Atlantic Ocean and Arctic Ocean.
It has the longest known lifespan of all vertebrate species (392 ± 120 years), and is among the largest extant species of shark. As an adaptation to living at depth, it has a high concentration of trimethylamine N-oxide in its tissues, which causes the meat to be toxic. Greenland shark flesh treated to reduce toxin levels is eaten in Iceland as a delicacy known as kæstur hákarl.
The Greenland shark is one of the largest living species of shark, with dimensions comparable to those of the great white shark. Greenland sharks grow to 6.4 m (21 ft) and 1,000 kg (2,200 lb), and possibly up to 7.3 m (24 ft) and more than 1,400 kg (3,100 lb). Most Greenland sharks observed have been around 2.44–4.8 m (8.0–15.7 ft) long and weigh up to 400 kg (880 lb). Males are typically smaller than females. It rivals the Pacific sleeper shark (possibly up to 7 m or 23 ft long) as the largest species in the family Somniosidae. The Greenland shark is a thickset species with a short, rounded snout, small eyes, and very small dorsal and pectoral fins. The gill openings are very small for the species' great size. Coloration can range from pale creamy-gray to blackish-brown and the body is typically uniform in color, though whitish spots or faint dark streaks are occasionally seen on the back.
When feeding on large carcasses, the shark employs a rolling motion of its jaw. The teeth of the upper jaw are very thin and pointed, lacking serrations. These upper jaw teeth, numbering from 48 to 52, act as an anchor while the lower jaw does the cutting. The lower teeth are interlocking and are broad and square, 50 to 52 in count, containing short, smooth cusps that point outward. Teeth in the two halves of the lower jaw are strongly pitched in opposite directions.
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Wikipedia