Hooded Seal

 

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Classification:

Global Population

Description and Natural History

Physical Description
Adult male hooded seals are approximately 2.5 meters (8.2 feet) long and weigh about 300 kilograms (660 pounds). Adult females measure approximately 2.2 meters (7.2 feet) and 160 kilograms (350 pounds). Mature males have a black inflatable sac that hangs over the front of the mouth from the nose and forehead. When inflated, the sac forms a crescent-shaped ‘hood’. Males can also inflate their nasal septum (inside of their nostril) into what looks like a red balloon. Young males develop the hood as they mature; females do not have the hood. Both sexes have a silvery gray background covered with dark blotches. The head is dark to behind the eyes and the fore- and hind-flippers are also dark.

Pups are born weighing about 20 kilograms (44 pounds) and gain up to five kilograms (11 pounds) per day before being weaned at four days of age -- the shortest lactation period of any mammal. Hooded seal pups, called bluebacks, are blue-gray on the back, distinctively separated from the silver-gray or yellowish sides and belly. They also have dark flippers and a characteristically dark face mask.

Natural History
Hooded seals share much of their range with harp seals, although they tend to live farther offshore and feed in deeper water. Because of this, the two species only gather together in the same areas during part of the breeding season.

Hooded seals are not easily separated into populations as harp seals are, although three groups have been recognized, based on where they breed: Off the east coast of Canada in the "Front" and in the Gulf of St Lawrence ("Gulf"); on the West Ice east of Greenland; and in the Davis Strait between Greenland and Canada.

Hooded seals give birth to one pup per year during the second half of March. The pups are nursed for only four days before the mother leaves them. Hooded seals are not as gregarious as harp seals. Mothers and pups are attended on the whelping patches by one or more aggressive males who wait for the opportunity to mate with the female after she weans her pup. Hooded seals are thought to wander more widely than harp seals but little is known about their distribution after leaving the molting patches in the Denmark Strait. The population estimate from 1996 is about 627,000 animals.

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Status of the Species

Status
Not listed.

Threats to the Species
Hooded seals are hunted annually in Canada. The present total allowable catch is 10,000 animals per year. Hooded seals are also taken off West Greenland by Norwegian sealers between March and May.

International Trade
The pelts of hooded seals are not differentiated from other species in the trade statistics, therefore the main purchasers of Canadian hooded seal pelts are the same as for harp seals: Norway, Canada and China. The most prized pelt, the hooded seal blueback, has not been legally traded with the European Union since 1983. It is now illegal in Canada to take blueback pups. Some meat may also be traded and penises are used in traditional medicine as “aphrodisiac” preparations (e.g. wine, tonics, powder, pill) to increase virility.

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Authors and Sources

Sources
Hammill, M.O. and G.B. Stenson. 2000. Estimated prey consumption by harp seals (Phoca groenlandica), hooded seals (Cystophora cristata), grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina) in Atlantic Canada. J. Northw. Atl. Fish. Sci. Vol 26:1-23.

Hannah, J.L.. 200. Seals of Atlantic Canada and the Northeastern United States. International Marine Mammal Association. 33pp.

Lavigne, D.M. and K.M. Kovacs. 1988. Harps and hoods: Ice-breeding seals of the Northwest Atlantic. University of Waterloo Press. Waterloo, Canada. 174pp.

Malik, S., P.J. Wilson, R.J. Smith, D.M. Lavigne and B.N. White. 1996. Pinniped penises in trade: A molecular-genetic investigation. Conservation Biology Vol 11(6):1365-1374.

Reijnders, P. S. Brasseur, J. van der Toorn, P. van der Wolf, I. Boyd, J. Harwood, D. Lavigne and L. Lowry. 1993. Status Survey and Conservation Actioan Plan: seals, fur seals, sea lions, and walrus. IUCN/SSC Seal Specialist Group. 88pp.

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