Mapping the forming narwhal tusk by large volume multiscale X-ray imaging

Narwhals are unique and poorly understood animals. Their tusk has a spiral macrostructure with highly anisotropic mechanical properties. The formation of the chiral tusk is not understood and the origin of this amazing biological structure thus remains elusive. Therefore, we propose to conduct high energy multiscale X-ray imaging of the tusk formation centre in both emerging and embedded tusk, the latter being the tusk that does not exit the skull to become an external dentition. We will image ~30 cm high, 10 cm diameter volumes at 25 µm supplemented by higher resolution images of selected subregions. This will allow revealing the enigmatic tusk formation mechanisms.