National Geographic:

The unicorn of the sea just got a little less mysterious.

Until now, how narwhals used their long tusks had been subject to much speculation by scientists.

Behavior captured for the first time on camera shows narwhals using the long tusks protruding from their heads to stun Arctic cod by hitting them, using jagged, quick movements. This behavior immobilizes the fish, making them easier to prey upon.

I knew narwhals didn’t spear fish with their tusk but it’s interesting to see how they do use it.