Narwhal

Narwhal
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea Family: Monodontidae Genus: Monodon Species: M. monoceros
Binomial name
Monodon monoceros Linnaeus, 1758
Narwhal range

The Narwhal (Monodon monoceros) is an Arctic species of cetacean with a body similar to that of a dolphin. It is rarely found south of latitude 70°N. It is one of two species of whale in the Monodontidae family (the other is the beluga). It is possibly also related to the Irrawaddy Dolphin.

The name "narwhal" is derived from the Old Norse words for 'corpse' and 'whale' to describe the mottled white and grey colouring of the skin of the adult.

Contents

1 Physical description 2 Behaviour 3 Population and distribution 4 Narwhal myths 5 Predation and conservation 6 References

Physical description

The conspicious characteristic of male Narwhals is their extraordinary long tusk which projects from the left side of their jaws and has a clockwise-oriented spiralled ridge. The tusk can be up to 3m long (compared with a body length of 4-5m) and weigh up to ten kilograms. One in 500 males has two tusks.

The purpose of the tusk has been the subject of much debate. Early scientific theories supposed that the tusk was used to pierce the ice covering the Narwhal's Arctic Sea habitat. Others suggested the tusk was used in echolocation. Nowadays scientists believe the tusk is primarily used for showmanship and for dominance - those males with the largest tusk are most likely to successfully attract a mate. Like the tusks of elephants, Narwhal tusks do not regrow if they break off.

Male Narwhals weigh up to 1.5 tons; the female, no more than a ton. Most of the body is pale with brown speckles in colour, though the neck, head and edges of the flippers and fluke are nearly black. Older animals are usually more brightly colored than younger animals.

Behaviour

These are quick, active mammals which feed mainly on species of cod that reside under ice-enclosed seas. In some areas their diet however seems to have adapted to feed on squid.

Narwhals normally congregrate in groups of about 5-10 in number. Sometimes several of these groups might come together, particularly in summer when they congregate on the same coast. Males use their tusks for jousting to establish a social hierarchy.

Narwhals are deep-divers. During a typical deep dive the animal will descend at two metres per second for eight to ten minutes, reaching a depth of upto 1000 m, spend perhaps a couple of minutes at depth before returning to the surface. The deepest recorded is 1164 m. Typical dive times are twenty minutes, with twenty five minutes recorded in exceptional cases.

Population and distribution

The Narwhal is found predominantly in the Atlantic and Russian areas of the Arctic. Individuals are commonly recorded in the northern part of Hudson Bay, Hudson strait, Baffin Bay, off the east coast of Greenland and in a strip running east from the northern end of Greenland round to eastern Russia (170° E). Land in this strip includes Svalbard, Franz Joseph Land and Severnaya Zemlya. The northernmost sightings of Narwhal have occurred north of Franz Joseph Land, at about 85°N.

Estimates of population have concentrated on the fjords and inlets of Northern Canada and western Greenland. Aerial surveys suggest a population of around 40,000 individuals. When submerged animals are also taken into account, the true figure may be in excess of 50,000.

Narwhals are a migratory species. In summer months they move closer to coasts. As the winter freeze begins they move away from shore, and reside in densely-packed ice - surviving in leads and small holes in the ice. As spring comes these leads open up into channels and the whale returns to the coastal bays.

Narwhal myths

The Narwhal remained an animal of legend until the 19th century. Their high north habitat was not visited by Europeans until that time - stories of their existence only reached the mainstream scientific community through those trading with Inuit hunters.

In even earlier times, the Narwhal gave rise to the legend of the unicorn in the middle ages. During that time Narwhal tusks (usually found washed-up on northern shores) were believed to have come from a horse-like creature that had healing powers; however, according to the legend, the creature was a wild beast that could only be captured by offering a virgin as sacrificial bait.

Through contact with Inuit in the seventeenth century the aquatic nature of the unicorn was discovered, from whence its legend as a sea monster flourished.

Predation and conservation

The main predators are Polar Bears and Orcas. Some Inuit hunt this species. In Greenland, traditional hunting methods are used, but high-speed boats and rifles are frequently used in northern Canada. PETA and other animal rights groups have long protested the killing of Narwhals.

References

• Narwhal, M. P. Heide-Jorgensen (pp783-787), in Encyclopedia of Marine Mammals, Perrin, Wursig and Thewissen eds. ISBN 0125513402da:Narhval

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