A peculiar feature in nature, the narwhal tusk can reach up to three meters in length and is a straight upper tooth that protrudes through the whale’s lip on the left side. Unlike other mammal tusks, it grows perfectly straight without any curves.
An international research team has uncovered the reason behind the straight growth of the narwhal tusk, attributing it to the unique pattern of opposing spirals. According to Henrik Birkedal from Aarhus University in Denmark, the discovery of two opposing spirals, one turning right and the other left, was a surprising revelation.
New research published in Nature Communications details how these opposing spirals enable the tusk to grow in a straight manner. The study originated when Birkedal was approached by a colleague in organic chemistry investigating the handedness of molecules. Intrigued by the consistent leftward spiraling of narwhal tusks, the team delved into understanding the molecular structure behind the tusks and spirals.
Through collaboration with biologists from Greenland and physicists from Sweden, the researchers employed advanced imaging techniques akin to CT scans to unveil the presence of two opposing spirals in the tusks. Comprising dentine and cementum, similar to human teeth but lacking enamel, these tusks exhibit a left-handed spiral in the outer layer of cementum and a right-handed one in the inner layer of dentine.
This discovery not only solves the mystery of the narwhal’s straight tusk but also holds promise in shedding light on the structural principles of human bones and analogous cases, as per Birkedal.
Renowned narwhal biologist Martin Nweeia from Harvard University praised the in-depth research on the unique narwhal tooth, emphasizing its primary function as a sensory organ rather than for defense or feeding purposes. Nweeia highlighted the importance of interdisciplinary research and collaboration with Indigenous communities for future studies on narwhals, stressing the value of integrating scientific knowledge with traditional insights for a comprehensive understanding.
The study’s findings open new avenues for research into these fascinating creatures, emphasizing the significance of diverse perspectives and interdisciplinary collaboration in advancing scientific understanding, as acknowledged by Birkedal.
