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Narwhal

[nahr' wuhl] Monodon monoceros [mon' uh don mon uh' ser uhs]

Narwhal

Description

The narwhal is a medium-sized whale, averaging 13-15 feet in length and weighing up to 3,500 pounds; females are smaller than males. It is mostly white with dark spots, but the top is always darker than the bottom. It has no dorsal fin, and the fluke is fan-shaped with a deep notch.

skull of a rare Narwhal with two tusks instead of oneThe most characteristic feature of the narwhal is its tusk, which is always spiral in a counter-clockwise (as viewed from the animal's perspective) direction and can be as long as 9 feet. Only present in males, the tusk is actually a greatly elongated tooth; the vast majority of male narwhals have only one tusk, on the left side, but rare specimens have been found with both teeth elongated into tusks. The exact purpose of the tusk is unknown, but it is believed to be used in competitions between males for mates.

Distribution and Habitat

Narwhals live in the coastal waters and rivers of the Atlantic and Russian portions of the Arctic, with populations often seen in Hudson Bay and in the waters between Canada and Greenland. Like all other whales, the narwhal must come to the surface to breathe, but it can stay submerged for much longer times than other whales. It can also dive to a depth of 4,500 feet, an ability that allows it to regulate its body temperature by changing the depth at which it swims (in the Arctic, deep water is often warmer than surface and near-surface water).

Although narwhals will migrate, they rarely travel long distances and always stay near coastlines. It appears that narwhal migration has more to do with the migration of its favorite foods than with weather conditions, as it is not uncommon for pods of narwhals to stay in ice-packed areas as long as there is a sufficient food source.

Diet

Narwhals feed on a variety of Arctic fish and cephalopoda, but have a preference for cod, halibut, squid, and shrimp.

Reproduction

Little is known about the courting and mating behavior of narwhals except that breeding tends to occur in mid-April. One calf is born after a gestation period of 15 months, and birth always takes place in a deep bay or inlet. Newborn calves are about 5 feet long and weigh about 180 pounds; they begin life dark blue-gray in color, and become olive brown on the back as juveniles before finally attaining adult coloration. Males reach sexual maturity at 8-9 years, females at 4-7 years.

Other Information

Narwhals usually move in groups of 20-30, but ther may be as many as 1,000 in one pod during migration. Group composition appears to vary considerably, with some pods consisting almost entirely of one or the other sex and others including members of both sex.

Conservation Status

The total number of narwhals in the wild has never been determined, but the species is not considered endangered.

Scientific Classification

phylum Chordata
subphylum Vertebrata
class Mammalia
order Cetacea
suborder Odontoceti
family Monodontidae
genus & species Monodon monoceros

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This page was last updated on June 24, 2017.