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Greenland shark Somniosus microcephalus (Bloch and Schneider) 1801


[Bigelow and Schroeder, 1948, p. 516.]

[Garman, 1913, pl. 15, figs. 4-6.]

Greenland shark (Somniosus microcephalus)

Figure 21.—Greenland shark (Somniosus microcephalus), female, about 5 feet 9 inches long. Teeth at center of mouth; lower teeth from midway along the jaw of a specimen about 11 feet long from the Gulf of Maine, about 1.8 times natural size. From Bigelow and Schroeder. Drawings by E. N. Fischer.


The Greenland shark is notable for its small dorsal fins, without spines, the second dorsal being of about the same size as the first, and for small pectorals hardly larger than the pelvics, coupled with the absence of an anal fin and with a tail of more fish-like form than that of most other sharks except for the mackerel-shark tribe. Bearing these points in mind, particularly the absence of an anal fin and of dorsal spines, it cannot be confused with any shark common in our Gulf. And while it resembles the rare Portuguese shark in the sizes and relative situations [page 54] of its dorsal and anal fins, in its general form, and in its teeth, it is easily separable from the "Portuguese," both by lacking any trace of spines in its dorsal fins, by its thorn-like and loosely spaced dermal denticles, and by its more lunate tail. It also grows much larger than the Portuguese shark. We need only note, further, that while its upper teeth are narrow and awl-like, its lowers are broad, squarish, forming a nearly continuous cutting edge, with the single cusp directed sharply outward; that its gill openings are short and located low down on the sides of the neck; that its eyes are very small; and that it is stout shouldered, with blunt rounded snout, as Scoresby pictured it more than a century ago.[43]


Blackish, coffee brown, or ashy-, purplish-, or slate gray, below as well as above; changing to bluish gray if the epidermis is rubbed off, as is apt to happen when one is caught; the back and sides are marked with many indistinct dark crossbars on some specimens.


This is one of the larger sharks. It is said to grow to a length of 24 feet, but 21 feet is the largest of which we find definite record,[44] and 16- to 18-footers are unusual. One of 16½ feet was reported from the Grand Banks in 1934; one of 16 feet off Portland, Maine, in 1846; one of about 15 feet off Cape Ann in 1849; and another of about that same size was caught on a long line north of Cape Ann in February 1931. Perhaps 8 to 14 feet is a fair average for adults, that is not often exceeded among the hundreds caught annually off West Greenland and around Iceland. The 21 foot British specimen mentioned above was said to weigh about 2,250 pounds; two Gulf of Maine specimens, each about 11 feet long, weighed about 600 and 650 pounds, respectively.


Off Greenland, and along the Labrador coast, the Greenland sharks tend to approach the surface in winter, often coming right up to the ice. But most of them withdraw in summer to 100 fathoms or deeper. And the few that visit our Gulf appear to hold rather closely to the bottoms of the deeper troughs, though a stray may come so close to the shore now and then, and into water so shoal as to blunder into a fish weir; one such event is on record for Passamaquoddy Bay.

This is one of the most sluggish of sharks, offering no resistance whatever when hooked, and it is entirely inoffensive to man.[45] But it is extremely [page 55] rapacious. It devours any carrion eagerly, such as whale meat, blubber from whaling operations, or the carcasses of young seals that are left on the ice off the Newfoundland-Labrador coasts. And its habit of gathering when there has been a big killing of narwhals in Greenland waters is proverbial. Apart from carrion (which cannot be available except on rare occasions), its diet includes a wide variety of fishes, large and small. Seals are a favorite food, and in view of its sluggishness, it is somewhat astonishing that it should be able to capture prey as active as seals, halibut, and salmon. The specimen from Cape Cod Bay, mentioned above, contained half a dozen flounders and a large piece (with hide and hair) that had been bitten out of the side of a seal. It is also known to eat crabs, large snails, even medusae. Objects as large as an entire reindeer (without horns), a whole seal, a 3-foot cod, and a 39-inch salmon, found in Greenland shark stomachs, give some measure of their appetite. In line with this, they will bite on any fish or meat bait, the more putrid and ill smelling the better.

Large numbers of soft eggs, without horny capsules, ranging in size up to that of a goose egg, have been found repeatedly in female Greenland sharks, but never any embryos, suggesting that this may be an egg-laying species.[46]

General range—

Northern Atlantic, from Polar latitudes south to the North Sea and accidentally to the mouth of the Seine and perhaps to Portugal in the east; south regularly to Newfoundland and the northern part of the Gulf of St. Lawrence in the west, and less commonly to the Gulf of Maine. It is represented in the Mediterranean region, in the North Pacific, and in the sub-Antarctic by forms that appear to be distinct, though closely allied to it.[47]

Occurrence in the Gulf of Maine—

Although there is no reason to suppose that the Greenland shark ever appears in our Gulf save as a straggler from the north, its presence there has been signalized on a number of occasions. Two specimens, for example, were taken in the neighborhood of St. Andrews in 1915 (one caught in a weir and the other on a long line). It has been reported off Eastport; off Cape Elizabeth whence 6 were landed at Portland between 1925 and 1948;[48] on Jeffreys Ledge, where one of about 15 feet was caught on a long line, on February 16, 1931;[49] near Cape Ann; off Marblehead and Nahant; in Massachusetts Bay; off Barnstable in Cape Cod Bay; at Provincetown; and in Cape Cod Bay off the entrance to the Cape Cod Canal, where one between 10 and 11 feet long was taken by a trawler in April 1924, landed in Boston and identified by us.

Recorded captures in the Gulf include small specimens as well as large, and have been for all four seasons of the year, suggesting that when a Greenland shark does stray southward to the Gulf, it may survive there for years. The local records are distributed so widely as to show that an odd specimen is to be expected anywhere in the deeper parts of the Gulf. And rumor has it that they were more numerous in our waters in early colonial times when Atlantic right whales were still being killed in numbers off the Massachusetts coast.[50]

Commercial importance—

This shark is not plentiful enough in our Gulf to be even of potential value. But it has long supported a fishery off northern Norway, around Iceland, and in West Greenland waters, chiefly for its liver oil.[51] In Greenland the flesh is dried also for dog food, and to a small extent in Iceland for human consumption. But it produces an intoxicant poisoning if eaten fresh, though it is wholesome if dried.[52]

[43] Arctic Regions, 1820, vol. 2, pl. 15, figs. 3 and 4.

[44] Jenkins, Fishes British Isles, 1925, p. 325.

[45] Tales to the effect that it attacks Greenlanders in their kayaks are apparently mythical, and Doctor Porsild, Director of the biological station at Disko, said that the Eskimos do not fear it as they do the killer whale; nor is there any authentic instance on record of a shark attacking a human being near Iceland.

[46] The Mediterranean Somniosus rostratus, on the contrary, bears living young.

[47] For recent discussion of the species of Somniosus, see Bigelow and Schroeder, Fishes Western North Atlantic, Pt. 1, 1948, p. 515.

[48] Reported to us by the late W. W. Rich.

[49] This one was landed in Boston, where we saw it.

[50] When they gather to feed on whale, narwhal, and seal carcasses in their northern home, they may linger for a long time in the vicinity.

[51] The annual catch off West Greenland was around 32,000 during the first decade of the present century.

[52] For accounts, see Jensen, 1914 (Selachians of Greenland, Mindesk. Jap. Steenstrup, vol. 2, No. 30, 1914, p. 12); also Clark (Science, N. Ser., vol. 41, 1915, p. 795).