The structure and variation of cheek teeth in the polar fox, Alopex lagopex, was analyzed on the basis of a sampling of 234 skulls, including two land and one island populations and using chi-square and Lilljefors criterion, and the variance analysis. The correlation matrices were compared by the Mantel test, and the entire set of correlation coefficients was analyzed using the principal component analysis. The cluster analysis was applied to reveal and represent a correlation pattern; the stability of correlation pleiads recognized by this analysis was assessed using a random subsampling procedures. The size of skull was shown not to affect the interdental structure. Nearly 37% of its total diversity is explained by the factors taken for the consideration; 8.9% is explained by the geographical factor, 17.1 and 10.6% of the total diversity fall on the age and sex differences, respectively. The integration of the toothrows (especially of the upper one) in polar fox is rather weak. The correlation structure of teeth has several interacting levels. The correlation between the bilateral teeth (premolars and molars) and adjacent teeth (minute premolars) is the highest one. Premolar and molar groups of the lower and upper toothrows are united at the next integration level; these "vertical" correlations are weaker than the previous ones, and various methods reveal different (biologically interpretable) pleiads. The carnassials are weakly integrated, their traits being included into different correlation pleiads. An overall interdental correlation pattern is discussed from the standpoint of the concept of integration levels, and the significant role of epigenetic processes in the integration pattern of toothrows is supposed. The results obtained make it clear that such kind of investigations should be based on a complex of methods that make it possible to analyze various aspects of morphological correlations.