- Researchers are using advanced imaging technology to study narwhal tusks in unprecedented detail, aiming to unravel some of its mysteries.
- A team from Aarhus University has revealed a double spiral structure in narwhal tusks, which enhances their mechanical properties.
- The double-spiral structure gives the tusk favorable mechanical properties, making it more stable against bending and twisting than a single spiral or a straight rod.
- The study published in the journal Nature Communications indicates that the tusk's building blocks grow in a double helix, with the outer layer spiraling left and the inner part spiraling right.
A new study published in the journal Nature Communications has unveiled the intricate double spiral structure of narwhal tusks, enhancing their resistance to mechanical stress. Researchers from Aarhus University utilized advanced imaging technology to analyze the tusks in unprecedented detail.125
The study reveals that the tusks are composed of two spirals: the outer layer, known as cementum, spirals left, while the inner layer, dentine, spirals right. This unique double-helix structure significantly improves the tusk's mechanical properties, making it more stable against bending and twisting compared to a single spiral or straight rod.
According to lead researcher Birkedal, the tusk's design is akin to tree rings, growing in bands that can be used to estimate the narwhal's age, which can reach up to 80 years. Birkedal notes, "The dominant hypothesis is that the narwhal tusk is for show—to establish social dominance or attract mates, for example—and not for hunting, at least not directly."
The findings suggest that the left-handed growth pattern of the tusk is genetically programmed and remains stable throughout the animal's life. This discovery not only sheds light on the tusk's function but also highlights the remarkable adaptability of narwhals in their environment.
The research team employed advanced x-ray scanners, described as 'turbocharged' versions of CT scanners, to uncover these details, emphasizing the tusk's complex biological architecture.
“The double-spiral structure, with a left-handed helix on the outside and a right-handed helix inside, provides the tusk with remarkable stiffness and strength. This genetic growth pattern remains stable throughout the narwhal's life, which can extend up to 80 years.”
Ars Technica
