The dimensional characteristics and morphotypic variability of the molars of the red voles, inhabiting the northern forest-steppe of the Tyumen region, are studied. It is shown that the dimensions of individual teeth are subject to age-related variability. Comparison of the dimensional characteristics of the molars of the red voles of the 3rd and 4th age groups revealed a reverse trend: a significant decrease in the width of M², length and width of M³, length and width of M₃, with p < 0,01. Probably, such a reduction in the size of the teeth indicates the abrasion of the teeth in the fourth age group. In young animals, this is associated with growth processes, and in adults – with abrasion of teeth, except for lengths M₁ and M¹, which are characterized by continued growth. The structure of the masticatory surface of the M³ tooth of the red voles is simplified with age as the tooth is rubbed. For the M₁ tooth, no age variability was detected.