Why Does a Narwhal’s Tusk Twist and What’s It Made Of?
Researchers found opposite spirals in the tusk’s outer and inner layers, a structure that makes it more stable against bending and twisting.
- An international research team led by chemist Henrik Birkedal of Aarhus University in Denmark published findings in Nature Communications revealing that narwhal tusks possess a double-helix structure of mineralized collagen providing exceptional strength.
- Despite growing over 6.6 feet long, narwhal tusk formation eluded scientists for decades; researchers previously understood the left-handed spiral shape but lacked knowledge of the interior molecular structure at atomic scales.
- Using particle accelerator X-ray sources at synchrotrons in Sweden, Switzerland, and France, the team mapped the tusk's interior, discovering the outer cementum layer forms a left-handed helix while the inner dentine layer forms a right-handed helix.
- The opposing double-helix structure makes tusks more stable against bending and twisting than single-spiral designs, with flexible fibers and stiff mineral matrix working together—insights that could help materials scientists design advanced materials for construction and medicine.
- Birkedal said researchers are working to analyze annual growth layer patterns to "map the life history of a narwhal through its tusk and thereby gain insights into living conditions for the whales in the arctic." Since narwhals live up to 80 years, their tusks form a historical record.
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13 Articles
On Tuesday, 18 August, several scientists presented in the scientific journal "Nature Communications" their conclusions on the tooth on the animal's head, its structure and its hypothetical role.
Living exclusively in the icy waters of the Arctic where their population is estimated at about 120,000 individuals according to IUCN, these marine mammals with a singular appearance and a massive body are particularly difficult to observe and study. They possess on the front of their head a perfectly straight twisted lance-like defense up to three meters long. In the Middle Ages, this appendix, without equivalent in the rest of the animal kingd…
The Narwhal's Tusk, a "Mythological Horn" that Was Thousands of Years Ahead of Materials Engineering
A study deciphers the elongated spiral that emerges from the skull of these sea unicorns, formed by two layers of teeth that grow in opposite directions and give it great strength.
The extraordinary engineering that builds nature's only straight tusk
The narwhal's defining feature – its continuously growing tusk – is the only straight structure of its kind seen in nature. Now, scientists have cracked the code on how these elusive Arctic whales grow such an impressive and unique tool.Continue ReadingCategory: Biology, Science, Refractor: Science & HealthTags: Marine Biology, Whale, Marine Innovations, Tools, Biomechanics, Sensory, Teeth, Arctic
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