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Abstract THE FUNCTIONAL AND EVOLUTIONARY MEANING OF NARWHAL DENTITION Martin T. Nweeia The male narwhal is distinguished by its long, straight, spiraled tusk horizontally impacted within the upper left side of the jaw and extending outward through the upper lip into its Arctic environment. By combining multidisciplinary scientific studies with Inuit traditional knowledge, this research has focused on discovering the functional and evolutionary meaning for this unique adaptation of teeth in mammals. Significant findings of microanatomy have shown the tusk to have sensory capabilities. A micro-tubule network extends from the inner pulpal core to the external surface. Analysis of tusk mineral/collagen ratios demonstrates an uncharacteristic reverse model of teeth in which the outer surface is comparatively soft with a rigid inner core. Additional studies of tusk microstructure in Odobenocetops, an hypothesized evolutionary link; tusk control genes established during fetal development; vestigial teeth microstructure; mathematical modeling for the tusk spiral, and electroencephalographic findings on living narwhal associated with tusk sensory input, will be integrated to the investigation results. Collection of traditional knowledge from 52 elders in High Arctic communities of Baffin Island and Greenland has revealed information about anatomy, migration and behavior that has contributed, guided and challenged scientific results. Significant observations of anatomy include morphological variation of the tusk in relation to Inuit classification of phenotype. Narwhal migration patterns have shifted during recent changing ice conditions. Behavioral observations of males leading large groups, “tusking” behaviors where males rub their tusks in non-aggressive encounters, and frequent sightings of smaller groups and pods separated by sex, contribute to the discussion of hypothesized tusk function. |