Why does the NARWHAL have a horn?

Answer 1

It is believed that the horn (Which is actually a tusk, a type of tooth) is used for nothing more than sexual identification. Males are the ones that have the tusk, located on the left incisor, though females can have them on rare occasions. 1 out of every 500 Narwhals has a second tusk on the right incisor, but there has only been one sighting of a female narwhal with two tusks.

Answer 2

The narwhal's "horn" is actually a tusk, which is a long, spiraled tooth that grows through the narwhal's upper lip. The exact purpose of the narwhal's tusk is still debated among scientists, but it is believed to play a role in mating rituals, sensory perception, and possibly even communication.