Abstract
We studied morphometric features of the spiral structure of the narwhal tusk and show that angular parameters of the arcs of the cementum layer determine the pattern of the spiral structure of the tusk. Given the straight shape of the tusk and the inclined pattern of the arcs of the cementum layer, the angular characteristics of the spiral were determined through the ratio of the legs of a right triangle, which was a basis for calculating the tangent of the angle of inclination. We found the angle of inclination through the arctangent. The tangent of the angle of inclination of the arcs of the spiral of the narwhal tusk is 2.39 ± 0.07, while the angle of inclination is 66.88 ± 0.61°. The indicators reflect the spiral morphology of the narwhal tusk. Researchers can use the data obtained in morphology practices, as well as in modeling the natural spiral structure in biomimetics.