Narwhals Sport Iconic Straight, Spiraled Tusks. Scientists Just Uncovered Some of the Eye-Catching Feature's Structural Secrets

Narwhals, often referred to as the unicorns of the sea, possess a distinctive "horn" that can grow up to ten feet in length. While this feature, technically a tooth, is not capable of performing magic, researchers believe it may serve as a tool for male narwhals to compete for mates or as a sensory organ. One unique aspect of this tusk is that it is the only known creature with a straight, spiraled, left-handed tusk.

This intriguing characteristic has been the subject of recent study by Henrik Birkedal and his team at Aarhus University in Denmark.

The researchers discovered that the elongated tooth is composed of two layers - an outer layer of cementum and an inner layer of dentine - that twist in opposite directions. This opposing spiral structure helps the tusk grow straight and strong. The cementum layer forms a left-handed helical pattern, while the dentine layer twists into a right-handed helical shape.

These opposing spirals contribute to the tusk's structural integrity, allowing it to withstand bending and twisting forces better than a single spiraled or non-spiraled rod.

The intricate boundary between the cementum and dentine layers appears to be even more complex than previously thought. Additionally, the opposing spiral structure can be seen in the annual growth layers of the tusk, similar to growth rings found in trees. This finding suggests that analyzing these growth patterns could provide insights into a narwhal's life history and living conditions in the Arctic.

Further research is needed to fully understand the formation of the tusk within the skull and its role in narwhal behavior. Martin Nweeia, a narwhal expert from Harvard University, expressed excitement over the new in-depth analysis, stating that the tooth is "the most extraordinary tooth on the planet."