Scientists Discover Double Spiral Structure Inside Narwhal Tusks Using X-Rays

For centuries, narwhal tusks have fascinated scientists and inspired myths. These long, twisted teeth, growing up to ten feet, were once sold as unicorn horns in medieval Europe, according to Scientific American and Business Line. Most male narwhals have a single, straight tusk that grows through the upper lip and twists in a left-handed spiral.

Despite their fame, the actual structure of narwhal tusks remained unclear. Previous studies described the tusk's outer spiral, but the internal architecture was poorly understood. Researchers hoped that modern imaging could reveal more about how these tusks grow and why they are so strong.

On August 18, 2026, several scientific outlets reported that researchers using advanced X-ray techniques had uncovered a surprise inside the narwhal tusk. Phys.org and Time.news wrote that the tusk contains a double spiral, or double helix, structure. This was the first time scientists had seen two opposing spirals within the tusk, rather than just the well-known external twist. The findings were published in Nature Communications, CBC reported.

Ars Technica explained that the tusk is made of dentine, cementum, and collagen fibrils, with hydroxyapatite, and that the double spiral arrangement may contribute to its resistance to bending. Popular Science and Discover Magazine highlighted the unusual mathematical properties of the tusk's formation, which had long puzzled biologists and mathematicians alike.

CBC emphasized that the two counteracting spiral layers inside the tusk help it grow straight, despite its twisted appearance. Vice and The Hindu picked up the story, noting that this discovery made the narwhal even more unusual among marine mammals. Time.news and Fanpage revisited the tusk's role in folklore, but now with a scientific explanation for its strength and straightness.

The double spiral structure inside narwhal tusks has now been confirmed by multiple outlets and peer-reviewed research. Scientists agree that this feature likely explains why the tusk can grow so long and remain straight despite the harsh Arctic environment.

Researchers are still investigating exactly how the double spiral grows and what evolutionary advantages it provides. The discovery has sparked new interest in narwhal biology and could influence how scientists study other animal structures with unique mechanical properties.

Open questions remain about the purpose of the narwhal tusk, which is still not fully understood. Scientists plan to keep studying its growth and function, as well as how the double spiral might inspire new materials or designs in engineering. Further research could also help explain why only some narwhals develop these remarkable tusks and how they use them in the wild.