Wild boar Sus scrofa Linnaeus, 1758 dental variability in two areas of the Iberian Peninsula

The skulls and mandibles of 182 wild boars from the Western Pyrenees (WP) and the Middle Ebro Valley (MEV), Aragon, Spain, were assessed for dental variability. We evaluated whether there were differences in the frequency and age and sex distribution between areas, and whether any differences might be related to their environments (acquired) or were heritable (congenital). Variability included hyperdontia and hypodontia (more or fewer teeth than is normal), persistence (presence of deciduous teeth in adults), rotation and malposition (teeth deviations from the vertical or horizontal axes, respectively), diastema (abnormal space between two teeth), injuries, tooth loss, and tartar. Acquired variability such as tartar and injuries were significantly more frequent in the WP, which might have been due to differences in diet between the areas (e.g., in WP, rooting was considerable). Among the congenital, the areas differed significantly in the frequency of diastema, which might have been a hereditary characteristic in the MEV. Overall, the incidence of rotations (100%) and malposition (90%) were high, which suggests that these are characteristics of the dentition, rather than abnormalities. Among the congenital, diastema (and the frequently associated hypodontia) was the most common, which we interpret as an incipient adaptation towards a reduction in the number of teeth as a response to a shift to a predominantly vegetarian diet.