Water voles (Arvicola sp.) are rodents which are numerous in the fossil record and serve as important biostratigraphic markers and indicators of palaeoclimate. They display high geographical and temporal morphological variation, but the evolutionary mechanisms behind this is still fairly unexplored. In this project, we will generate modern and ancient DNA (aDNA) data from a large dataset of water voles across their geographic range throughout Eurasia (mainly focusing on Europe). The samples range in age from modern day up to 1 million years ago, thereby spanning across much of the Pleistocene which is an epoch characterized by major shifts in climate. The goals of this project is to 1) investigate the genetic structure of modern water voles, e.g how many evolutionary lineages exist today, and where do they exist? 2) investigate the evolutionary history of water voles across the Pleistocene through the use of aDNA, e.g. how many evolutionary lineages existed in the past, and how did they evolve? 3) apply a metagenomic approach to understand how the fossils were accumulated at different sites, since water voles are prey species of many predators. Through these analyses we hope to gain important insights into the evolution of this genus which might have responded to climate shifts through local extinctions and recolonizations, hybridization, or adaptation. Furthermore, we aim to gain insights into past ecological interactions by identifying predator species that predated on water voles at different sites during certain time periods. From a larger perspective, these findings will be useful to understand modes of evolution which can either happen gradually or in rapid bursts, as well as provide important information regarding the morphological evolution of water voles which can lead to more accurate dating methods of archaeological sites.