Narwhal (meaning "corpse whale" in Old Norse)
is a rarely seen Arctic whale. This social whale is
known for the VERY long tooth that males have. Very
little is known about this whale.
All narwhals have two teeth in their upper jaw. After
the first year of a male narwhal's life, its left
tooth grows outward, spirally. This long, single tooth
projects from its upper jaw and can grow to be 7-10
feet (2-3 m) long. Tusks are usually twisted in a
counterclockwise direction and have a hollow interior.
The tusk's function is uncertain, perhaps used as
a formidable jousting weapon in courtship and dominance
rivalry, in obtaining food, and/or for channeling
and amplifying sonar pulses (which they emit). The
tusk is not used in hunting. Long ago, narwhal sightings
reinforced (or started) the unicorn legends.