The unicorn, according to mythology, was a horselike creature with a single horn growing from its forehead. No such creature has ever existed; but the term unicorn or unicorn fish is sometimes applied to the narwhale, a type of toothed whale, which grows to a length of 15 or 16 feet and is found primarily in arctic waters.
The peculiar development of one of its teeth is responsible for the name of unicorn. At birth, both male and female narwhales have a few teeth, but they very shortly degenerate, except for two in the upper jaw. These two seldom become functional in the female, but in the male, the left tooth continues to grow.
It grows forward straight through the upper jaw and lip, spiraling upon itself in a clockwise direction. The right tooth normally does not develop even in the male, but occasional specimens have been collected in which both teeth had grown into tusks, and for some unknown reason, both the tusks spiraled in the same direction.
Exact measurements are scant, but it is probable that the tusks sometimes grow to a length of nine or ten feet. The function of this enormous tooth is not definitely known.
There have been reports that it is used as a weapon for fighting, for punching holes in the ice, and for spearing fish, but, so far as I am aware, none of these reports have been confirmed.
The narwhale has figured rather conspicuously in connection with the mythical unicorn of European folklore.
Norsemen from Iceland, where the narwhales were at one time rather numerous, collected some of the teeth and took them to Europe, trading them as genuine unicorn horns to the delighted Europeans.
The chances are that no true description was given of the original owner of the “horn,” since, according to mythology, the unicorn was supposed to be a graceful, horselike creature, not at all like the leg-less, clumsy, blunt-faced narwhale.