The climatic fluctuations of the Quaternary (<2.5 Ma) provide an appropriate background to the study of the influence of the actual climatic change on the biodiversity. For example, the last glaciation, including the Last Glacial Maximum (~19000 yrs), shaped the geographic distribution observed on actual species.The aim of my thesis was to better understand how a forest-related species of rodent, the bank vole (Myodes glareolus), was affected by the Quaternary cycles. In this way, I used a morphometric approach of diverse characters involved in the mastication process (mandible and molars) to quantify the shape differentiation related to the influence of several factors.Contrasted results were observed, the mandible being widely influenced by the age structure of the studied populations. In contrary, molars can be used as relevant markers of the biogeographic structuration of the bank vole.The study on the size and shape variations of actual specimens needed the integration of various fields of research, dealing with the genetic heritage of the organisms, their development, the environment etc.It allowed a better comprehension of the complexity of the processes leading to a wide diversity of shape patterns within the bank vole.
