The narwhal has a rounded, robust body with no dorsal fin. The head is rounded, with a bulbous melon that protrudes over the slight beak in adult animals. Pectoral fins are broad and short whilst the tail fluke becomes strongly convex with age, particularly in males. The most distinctive feature is the tusk, which is actually the left upper front tooth that grows to up to 2.7 metres in length and can weigh 10kg. This occurs in adult males and very occasionally in females, otherwise narwhals are toothless. Sometimes the right upper front tooth also grows. Skin tone lightens with age, with the oldest animals being almost white, but normally with some dark blotches. Adults can reach up to 4.7 metres long (excluding the tusk).
Habitat and DistributionEdit
Narwhals are found in the Arctic Ocean and their distribution is largely determined by seasonal pack ice movements. There have been several sightings of narwhals along the east coast of the UK, although these represent extralimital records. There has been one live sighting in the Hebrides (1976) and no strandings.
Aggression between males can result in wounds and scars on the heads of narwhals and broken tusks. The tusk may be used during these fights to assert dominance over other males. Occasionally large numbers may be trapped by fast-forming ice and are predated by polar bears.
Food and ForagingEdit
Narwhals are a deep diving species that will feed on fish, shrimp and squid in the water column as well as taking bottom-dwelling species including halibut, flat fish and crabs. The tusk is not thought to be used during feeding.
Status and ConservationEdit
The current population of narwhals is estimated at 35,000 to 50,000 animals. They were historically hunted for their skins, meat, oil and tusks; skins and tusks continue to be of great commercial value in parts of Canada and Greenland. The main threat to narwhals is still hunting as techniques and equipment are now much more sophisticated, resulting in more successful hunts. Narwhals are also subject to threats including habitat degradation, pollution and reduction of prey due to overfishing. Narwhals are protected under UK and EU law, principally under Schedule 5 of the Wildlife and Countryside Act 1981, the Nature Conservation (Scotland) Act 2004 and by the 1992 EU Habitats and Species Directive.
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