Title: NOAA Ocean Explorer: Tracking Narwhals in Greenland: Biology
Headings: 
The Biology and Ecology of Narwhals
Dr. Kristin Laidre, Polar Science Center
Applied Physics Lab, University of Washington
References:

Content: Narwhals have a black and white mottled skin pattern and are white underneath. This coloration contributed to their name. The old Norse prefix “ Nar ” means “corpse” and “ hval ” means “whale”. Thus “corpse whale” refers to how their skin color resembles that of a drowned sailor. The narwhal is an odontocete or toothed whale, but is different from all other toothed whales in that it has no teeth in its mouth. Instead the male develops a long straight tooth (or tusk) that protrudes 2-3 m out of the upper left jaw. The tooth grows in a counterclockwise spiral. The myth of the unicorn comes from the narwhal tusk. Tusks exported from the Arctic, perhaps by the Vikings, reached Europe, the Mediterranean, and even the Far East as early as the Middle Ages. The tusks were sold without a good description of the animal from which they came.