Linnaeus, 1758 - Narwhal
Distinctive Characteristics
Narwhals are characterized by a robust body, relatively small, bulbous head with little or no beak, short blunt flippers that turn up at the tips in adults, absence of a dorsal fin (however, a slight dorsal ridge is present), and oddly shaped flukes. The flukes of adults become straight to concave on the leading edge, and convex on the trailing edge. They are deeply notched and the tips tend to curl upwards, especially in older animals.
Young narwhals are uniformly grey to brownish grey. As the animals age, black mottling develops on the back and sides, and the belly becomes light grey to white (with some dark mottling). Older animals often appear nearly white, with some black still remaining on the appendages.
There are only 2 teeth, both in the upper jaw. In females, these almost always remain embedded in the upper jaw bones, but in males the left tooth normally grows out through the front of the head and becomes a tusk up to 3m long. Occasionally, females with a tusk or males with 2 erupted tusks are seen.
Can be confused with
The narwhal is likely to be confused only with the white whale. Young white whales, especially, can look like narwhals, because of their grey coloration. The absence of blotching on white whales is probably the best guide, and male narwhals can be easily distinguished by their tusks.
Size
Adult females can be up to 4.2 m and males up to 4.7 m long (exclusive of the tusk). Large narwhals can reach weights of up to 1600 kg. Narwhals are about 1.6 m long at birth.
Geographical Distribution
This is an arctic species; it is found mostly above the Arctic Circle year-round. The principal distribution of the narwhal is from the central Canadian Arctic, eastward to Greenland and to the central Russian Arctic. They are rarely observed in the eastern Russian Arctic, Alaska, or the western Canadian Arctic. There are annual migrations, primarily to open water in autumn and back to inshore waters in spring. Three stocks are recognized on the basis of distribution and migration patterns.
Biology and Behaviour
Most pods of narwhals consist of 2 to 10 individuals, but there is some evidence that these groups are often parts of large dispersed herds of hundreds or even thousands of individuals. There is some age and sex segregation of narwhal groups, and all-male groups are common.
The tusk of male narwhals has long been a source of controversy. It now is generally agreed that the tusk is used in male-to-male competition for females. It is used perhaps primarily as a display, although male narwhals have been seen “sparring” with their tusks held above water.
Young narwhals are born mainly in summer, from July through August.
Fish, squid, and shrimp make up most of the narwhal's diet. They feed, at times, in deep water and possibly at or near the bottom.
Exploitation
Narwhals have been hunted for many centuries, both by Eskimos and by Europeans. Often sold for a high price as the horn of a unicorn, the tusk was, and still is, a much sought-after prize. No strictly commercial hunting occurs today; however, narwhals are still hunted for “subsistence” by Canadian and Greenlandic natives. Throughout the 1980s, the annual kill was estimated to be less than 1000 individuals. Oil and gas activities and pollution are other potential threats to narwhal populations.
IUCN Status
Insufficiently known.