Narwhals are a medium sized tooth whale closely related to belugas. Animals are born dark grey and turn black and white as they age with a black and white mottled pattern on their backs and white on the underside. Adult males weight an average of 1,600 kg, adult females 900 kg, and newborns average under 100 kg. Narwhals can grow to a length of around five meters, excluding the tusk which can reach 3 meters. The left tooth protrudes in males to form a counter clockwise spiralling ivory tusk while the other stays embedded in the jaw. While tusks in females and double tusks in males do occur, it is uncommon. While there is some debate on the purpose of the tusk, it is generally considered to be a secondary sexual trait like the tail feather display of a male peacock or the antlers on a deer.
A long-lived and slow reproducing species, narwhals are currently thought to have a lifespan of up to 90 years.
A female narwhal is sexually mature at between four and nine years old. Gestation lasts 14 to15 months and most calves appear to be born between July and August, although calves have been seen at the floe edge as early as late May. Female narwhals give birth to one calf about every three years.
Narwhal eat a small variety of fish and invertebrates including Greenland halibut (Reinhardtius hippoglossoides), Polar cod (Arctogadus glacial), Arctic cod (Boreogadus said) and squid (Gnats fabric). Narwhal diet is assumed to change seasonally with intense feeding happening in deep waters in the winter months.
Narwhals travel in small groups called pods containing a few animals or a few hundred individuals. Large groups can often be seen together during migration. Narwhals swim on average between 3 to 8 km/hr but can move at much faster speeds when a threat is percieved. They are one of the deepest diving animals in the world with dives recorded at depths of more than 1,500 meters. Long dives may last up to 30 minutes, while average dives range from 3 to 5 minutes in length.
Narwhals inhabit northern reaches of the globe generally above 60°N. They are semi-circumpolar in nature in that they mainly inhabit portions of the Arctic made up of Eastern Canadian Arctic and European Arctic waters. Although little is known about narwhal habitat needs, it is known that they prefer deep water in both summer and winter. In summer, narwhal range in coastal areas with both deep water and shelter while their winter is spent farther offshore. Similar to beluga, they are thought to return to the same locations in the Arctic year after year. Ice, water depth and the presence of upwellings may all play a role in habitat selection.
For management purposes narwhal are split into populations (or management stocks) which are defined and labelled by their summer grounds. The estimates below are based on available published data and do not include all known populations.
Narwhals are vocal animals and make a wide range of click and whistle sounds. They use echolocation like belugas to find prey, navigate, and communicate. A 'creaking door' sound is an identifiable narwhal vocalization.
Narwhal are part of an important subsistence harvest in the Arctic. Harvested year round but mainly in the summer, narwhal are important to the culture, economy, and food security of Inuit communities in the Arctic. Muktuk, or skin and blubber, is a favorite traditional food item across the north and tusks are sold or sometimes made into carvings.
There is much uncertainly about summering populations as it related to hunting pressures as well as the affect of development and increased shipping and noise on narwhal. As a highly ice associated species with a narrow prey preference, it is unknown how changes in climate and sea ice will affect this species.