AskDefine | Define narwhal

Dictionary Definition

narwhal n : small arctic whale the male having a long spiral ivory tusk [syn: narwal, narwhale, Monodon monoceros]

User Contributed Dictionary

English

Etymology

From Dutch narwal or Danish narhval, wal/hval meaning ‘whale’ and nar- from Old Norse nár ‘corpse’. Cf. Icelandic náhvalur.

Noun

  1. an Arctic cetacean, about 20 feet long; the male has a single twisted pointed canine tooth or tusk projecting forward like a horn.

Scientific names

Synonyms

Translations

Extensive Definition

The Narwhal (Monodon monoceros) is an Arctic species of cetacean. It is a creature rarely found south of latitude 70°N. It is one of two species of white whale in the Monodontidae family (the other is the Beluga whale). Narwhal means "corpse whale" in Danish. The Narwhal is also commonly referred to as the Moon Whale.

Taxonomy

The Porpoise was one of the many species originally described by Linnaeus in his Systema Naturae. The English name narwhal is derived from the Irish name narwal, which in turn comes from the Portuguese narhval. This is based on the Old Norse word nár, meaning "corpse". This is a reference to the animal's color. In some parts of the world, the Narwhal is colloquially referred to as a "rimfish". In Inuit language the narwhal is named ᕿᓚᓗᒐᖅ or qilalugaq.

Description

The most conspicuous characteristic of male narwhal is their single extraordinarily long tusk, an incisor that projects from the left side of the upper jaw and forms a left-handed helix. The tusk can be up to three metres (nearly 10 ft) long (compared with a body length of 7–8 m [23–26 ft]) and weigh up to 10 kilograms (22 lbs). About one in 500 males has two tusks, which occurs when the right tooth, normally small, also grows out. Although rare, a female narwhal may also produce a tusk. There is a single recorded case of a female with two tusks.
The purpose of the tusk has been the subject of much debate. Early scientific theories suggested that the tusk was used to pierce the ice covering the narwhal's Arctic Sea habitat. Others suggested the tusk was used in echolocation. More recently, scientists believed the tusk is primarily used for showmanship and for dominance: males with larger tusks are more likely to successfully attract a mate. This hypothesis was suggested by the activity of "tusking", in which two males rub their tusks together.
However, recent work by a research team led by Martin Nweeia suggests that the tusk may in fact be a sensory organ. Electron micrographs of tusks revealed millions of tiny, deep tubules extending from the tusk's surface, apparently connecting to the narwhal's nervous system. While such tubules are present in the teeth of many species, they do not typically extend to the surface of healthy teeth. The exact sensory purpose of the tusk remains unknown, but scientists now hypothesize that it may detect temperature, salinity, pressure, and/or particulate makeup of the water in which the narwhal swims. Unlike the tusks of elephants, narwhal tusks do not regrow if they break off. If damaged, however, the tusks can repair themselves to a certain extent.
Male narwhals weigh up to 1,600 kg (3,500 lb), the female around 1,000 kg (2,200 lb). Most of the body is pale with brown speckles in color, 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 methods and usual diet

Narwhals are quick, active mammals which feed mainly on species of cod that reside under ice-enclosed seas.
In some areas their diet seems to have adapted to include different squid, shrimp, and various fish, such as schooling pelagic fish, halibut, and redfish. Canadian Researcher William Sommers has found that when food is scarce, narwhals will even eat baby seals. Narwhals normally congregate in groups of about five to ten. Sometimes several of these groups might come together, particularly in summer when they congregate on the same coast.
At times, male narwhals rub their tusks together in an activity called "tusking". Recent findings of a marine mammal researcher at the Smithsonian Institution showed that the tusk also plays a role in the animal's sensory perception, with as many as 10 million tiny nerve endings reaching the surface of a tusk (which is a modified tooth). This suggests that the tusking may simply be a way of clearing encrustations from the sensory tubules, analogous to brushing teeth.
Narwhals prefer to stay near the surface. During a typical deep dive the animal will descend as fast as 2 m/s for eight to ten minutes, reaching a depth of at least 1,500 m (5,000 ft), spend perhaps a couple of minutes at depth before returning to the surface.

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.
The world population is currently estimated to be around 50,000 individuals. Most estimates of population have concentrated on the fjords and inlets of Northern Canada and western Greenland. Aerial surveys suggest a population of around 20,000 individuals. When submerged animals are also taken into account, the true figure may be in excess of 25,000.
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 narwhals return to the coastal bays.

Predation and conservation

The main predators of the narwhal are polar bears and Orcas. Inuit people are allowed to hunt this whale species legally. The northern climate provides little nutrition in the form of vitamins which can only be obtained through the consumption of seal, whale, and walrus. The livers of these animals are often eaten immediately following the killing by the hunting party in an ancient ceremony of respect for the animal. In Greenland, traditional hunting methods in whaling are used (such as harpooning), but high-speed boats and hunting rifles are frequently used in Northern Canada. PETA and other animal rights groups have long protested the killing of narwhals. Narwhals usually travel in pods of 10-100.
A study published in April 2008, in the peer-reviewed journal Ecological Applications found the Narwhal to be the most potentially vulnerable to climate change when a risk analysis of other Arctic Marine Mammals was conducted. The study quantified the vulnerabilities of 11 year-round Arctic sea mammals.

Cultural references

In Inuit legend, the narwhal was created when a woman holding onto a harpoon had been pulled into the ocean and twisted around the harpoon. The submerged woman was wrapped around a beluga whale on the other end of the harpoon, and that is how the narwhal was created.
Some medieval Europeans believed narwhal tusks to be the horns from the legendary unicorn. As these tusks were considered to have magic powers, Vikings and other northern traders were able to sell them for many times their weight in gold. The horns were used to make cups that were thought to negate any poison that may have been slipped into the drink. During the 16th century, Queen Elizabeth received a carved and bejeweled narwhal tusk for £10,000 — the cost of a castle. The tusks were staples of the cabinet of curiosities.
The truth of the tusk's origin developed gradually during the Age of Exploration, as explorers and naturalists began to visit Arctic regions themselves. In 1555, Olaus Magnus published a drawing of a fish-like creature with a horn on its forehead.

Gallery

References

External links

narwhal in Min Nan: Chi̍t-kak
narwhal in Catalan: Narval
narwhal in Danish: Narhval
narwhal in German: Narwal
narwhal in Spanish: Monodon monoceros
narwhal in Esperanto: Narvalo
narwhal in Persian: ناروال
narwhal in French: Narval
narwhal in Scottish Gaelic: Muc-mhara adharcach
narwhal in Croatian: Narval
narwhal in Interlingua (International Auxiliary Language Association): Narval
narwhal in Ido: Narvalo
narwhal in Icelandic: Náhvalur
narwhal in Italian: Monodon monoceros
narwhal in Hebrew: חדשן חדקרן
narwhal in Kalaallisut: Qilalugaq qernertaq
narwhal in Georgian: მარტოკბილა
narwhal in Lithuanian: Narvalas
narwhal in Hungarian: Narvál
narwhal in Dutch: Narwal
narwhal in Japanese: イッカク
narwhal in Norwegian: Narhval
narwhal in Polish: Narwal
narwhal in Portuguese: Narval
narwhal in Russian: Нарвал
narwhal in Slovenian: Enorog
narwhal in Finnish: Sarvivalas
narwhal in Swedish: Narval
narwhal in Turkish: Narval
narwhal in Chinese: 一角鲸
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