“Wisdom” tooth of the narwhal and other secrets of the skull revealed by CT

In 2025, after a two-year journey from Greenland to Japan, the full skeleton of an endemic Arctic whale, the narwhal (Monodon monoceros), measuring ~5 meters in length, was delivered to the Hokkaido University Museum in Sapporo. Currently, the Arctic Research Center is preparing the skeleton for an exhibition within the ArCS-3 project.

On February 12, 2026, for research and exhibition purposes, the tusk, skull, and lower jaw (i.e., mandible) of the narwhal were imaged with Computed Tomography (CT). This work is a collaboration between Dr. Evgeny Podolskiy (Arctic Research Center, Hokkaido University, Japan), Dr. Genya Shimbo (Faculty of Veterinary Medicine, Hokkaido University, Japan), and Dr. Sung-Min Park (College of Dentistry, Dankook University, Republic of Korea).

The CT data were collected at the Faculty of Veterinary Medicine, Hokkaido University, using a multi-slice CT system (Toshiba, Prime Aquilion). The preliminary digital three-dimensional models were created from these CT images and are shown here. The data reveal fine details of the head, including an impacted tusk (~20 cm long), a socket of the main tusk, an embedded vestigial tooth (~4.5 cm), an asymmetrical skull structure, and a hollow, spiraling tusk structure with annual layers.

For further details about this ongoing work or permission to use images, contact Dr. Podolskiy (e.podolskiy[_at_]arc.hokudai.ac.jp).
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