[The morphological variability coordinated with the population cycle of the widely distributed (the water vole Arvicola terrestris L.) and mountain (the big-eared vole Alticola macrotis Radde) vole species].

This paper presents an analysis of variation of skull size and shape in the course of population cycles of two ecologically different vole species: water vole and high-mountain vole. We have found consistent changes of the direction, rate, and balance of morphogenesis during population cycles. We discuss the role of intra-populational factors and inter-populational variation during the territorial expansion of the species.