The narwhal is a medium-sized toothed whale that possesses a large "tusk" from a protruding canine tooth. It lives year-round in the Arctic waters around Greenland, Canada and Russia. Like the beluga, narwhals are medium-sized whales. For both sexes, excluding the male's tusk, the total body size can range from 13 to 18 ft; the males are slightly larger than the females.
Narwhals do not have a dorsal fin and their neck vertebrae are jointed like those of most other mammals, not fused as in dolphins and most whales. As with most toothed whales, narwhals use sound to navigate and hunt for food. Sounds may be created via air between chambers near the blow-hole, and reflected off the sloping front of the skull.