X-rays add new twist to narwhal's spiral tusk

CT scans of a narwhal tusk have revealed a surprising twist to the already fascinating structure. While narwhals are toothed whales known for their distinctive spiral tusk, the new research indicates that these tusks may possess not just one, but two internal spirals - one oriented in the opposite direction. This intriguing discovery was published in the journal Nature Communications.

Inuit legend suggests a mystical tale behind the tusk's origin, claiming a woman was turned into the animal herself after being dragged by a harpoon rope hooked to a narwhal. Her twisted hair turned into the spiral tusk. In reality, the tusk is a canine tooth from the left upper jaw of male narwhals. It emerges through the lip when males reach two or three years old and can grow up to 1.5 to 2 meters in length.

While there is consensus that these tusks evolved via sexual selection as a symbol of social status, their precise function remains debated. Females typically do not develop such prominent tusks, which further adds to the mystery. Despite this, males who develop these tusks tend to outlive their less fortunate counterparts.