Narwhal Physical Description Behaviour Population And

The Narwhal (Monodon monoceros) is an Arctic species of cetacean similar in size and shape to 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 word for 'corpse' to describe the mottled white and grey colouring of the skinThis article is about skin in the biological sense. For other uses of skin see skin (computing) and skinhead. Regarding exposure of the skin to be seen by others, or prevention of this, see nudity, nudism, modesty, clothing. Fruits such as oranges also ha of the adult.

1 Physical description

The conspicious characteristic of male Narwhals is their extraordinary long tuskA tusk is an extremely long tooth of certain mammals that protrudes when the mouth is closed. Tusk-bearing mammals include elephants, warthogs, walruses, and narwhals. Tusks are used to produce ivory, which is used in artifacts and jewelry, and formerly i 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 weight 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 flike are nearly black.

This small whale is some 4-5 m long, excluding the tuskA tusk is an extremely long tooth of certain mammals that protrudes when the mouth is closed. Tusk-bearing mammals include elephants, warthogs, walruses, and narwhals. Tusks are used to produce ivory, which is used in artifacts and jewelry, and formerly i, generally pale with speckled upperparts. MaleThe word male has the following meanings: In biology, it refers to one half of a heterogamous reproduction system, where the female is the other half. The male sex comprises those organisms that produce sperm cells (which is defined as the smaller gamete) Narwhals have a single, long, straight tusk projecting from the left side of their jawThe jaw is either of the two opposable structures forming, or near the entrance to, the mouth. In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw''. In arthropods, the jaws are chitinouss, with a left to right spiralled ridge. The tusk is up to 2.5 m long. One in 500 males has two tusks. Older animals are usually more brightly colored than younger

2 Behaviour

These are quick, active mammalSubclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorps 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 hierarchyA hierarchy (Greek hieros sacred, arkho rule) is a system of ranking and organizing things. Different fields use the word in slightly different ways, but a particular definition (below) captures the core of almost all uses. Originally, "hierarchy" meant ".

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.

3 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.

4 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.

5 Predation and conservation

The main predators are Polar Bears, Orcas and Walruses. Some Inuit hunt this species. In Greenland, traditional hunting methods are used, but high-speed boats and rifles are frequently used in northern Canada.

6 References

Narwhal, M. P. Heide-Jorgensen (pp783-787), in Encyclopedia of Marine Mammals, Perrin, Wursig and Thewissen eds. BooksEnthsiast.com

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