Narwhal (Monodon monoceros) COSEWIC assessment and status report: chapter 3

• Previous page
• Table of contents
• Next page

Species Information

Name and classification

Narwhals (Monodon monoceros Linnaeus, 1758) are mammals belonging to the genus Monodon (Linnaeus, 1758), family Monodontidae (Gray, 1821– white whales), suborder (Odontoceti Flower, 1867– toothed whales), and order Cetacea (Brisson, 1762– cetaceans, whales). They are the only species in the genus Monodon. No subspecies have been identified. Common names for the species include narwhal, sea unicorn, narwhale, narval (French, Swedish, Spanish), narhval (Danish, Norwegian), itsu-keku (Japanese), rogozub (Russian), and enhorned hortand (Swedish). Inuit use a variety of descriptive words in Inuktitut to identify narwhal (J. Kilabuk, pers. comm. 2002). These include tuugaalik (with tusk), qirniqtaq qilalugaq (black whale), and Allanguaq (with black and white dots). The latter is commonly used in different regions of the Arctic.

Description

Narwhals are medium-sized toothed whales that lack a dorsal fin and have convex-shaped tail flukes (Figure 1). Like their close relatives, the beluga (Delphinapterus leucas), the colour of narwhals changes with age. The skin of newborn narwhals is an uneven grey or bluish grey, which changes to a uniform black or bluish black soon after weaning (Arvy 1978; Reeves and Tracey 1980). As the animal matures, white streaks and patches begin to develop around the anus, genital slit and navel, and spread over the entire ventral surface and onto the flanks. Adults are white to creamy yellow on the belly and mottled grey to black on the back. Very old animals, especially males, are almost completely white.

Adult narwhals are unique among toothed whales in having only two teeth (Eales 1950). These teeth are embedded horizontally in the maxilla of the upper jaw, one on each side. In most adult males, the left tooth forms a very long straight ivory tusk that spirals to the left along its long axis (Dow and Hollenberg 1977). Females with a tusk, males without a tusk, and males and females with two tusks are rare (Hay and Sergeant 1976; Reeves and Tracey 1980; Reeves and Mitchell 1981).

Adult male narwhals are larger on average than adult female narwhals. Males taken at Arctic Bay in 1986-89 averaged 4.58 m (range 3.96-5.40 m, SD 0.203 m, n = 56) and females averaged 4.13 m (range 3.56-4.94 m, SD 0.331 m, n = 20) (Roberge and Dunn 1990). These individuals were significantly larger (P<0.001) on average than male (mean 4.35 m, range 3.90-4.86 m, SD 0.226 cm, n = 37) and female (mean 3.81 m, range 3.48-4.20 cm, SD 0.216 m, n = 17) narwhals taken at Pond Inlet in 1982-83 (Weaver and Walker 1988). Newborn calves are typically about 1.60 m long (Hay 1984; Neve 1995a).