Animal guides
Is a Narwhal's Tusk Really a Horn?
The Arctic's so-called unicorn does not carry a horn: its famous spiral is a tooth with social and sensory roles.
Published July 15, 2026
A narwhal can look like a whale with a unicorn horn, but the famous spiral is not a horn at all. It is a tooth. In most adult males, the left tooth grows out through the upper jaw and can become several metres long.
One very long tooth
Narwhals have teeth in the upper jaw, but they usually remain embedded. In males, the left tooth commonly grows forward into the tusk. Females rarely have one, although exceptions occur. NOAA describes the tusk as a spiralled tooth, not a separate bone or a horn.
Photo by Kristin Laidre via Wikimedia Commons, public domain.
What is it used for?
The tusk is linked to male social status and may help with nonviolent assessment between males. Researchers also think it can act as a sensory tool, detecting changes in the surrounding water. It is not best understood as a weapon used all the time.
Why are narwhals hard to study?
Narwhals live in Arctic waters that can be dark, remote, and covered by sea ice. They dive deeply and move with seasonal ice, so even basic observations are difficult. That means some questions about tusk use still need careful study rather than a simple answer.
Photo by Gazprom neft via Wikimedia Commons, CC BY-SA 4.0.
The short answer
A narwhal tusk is a long, spiralled tooth, usually found on a male. It helps explain the unicorn legend, but it also has real biological roles in the social and sensory life of an Arctic whale.