Wikipedia
The Arvicolinae are a subfamily of rodents that includes the voles, lemmings, and muskrats. They are most closely related to the other subfamilies in the Cricetidae (comprising the hamsters and New World rats and mice). Some authorities place the subfamily Arvicolinae in the family Muridae along with all other members of the superfamily Muroidea. Some refer to the subfamily as the Microtinae or rank the taxon as a full family, the Arvicolidae.
The Arvicolinae are the most populous group of Rodentia in the Northern Hemisphere. They often are found in fossil occlusions of bones cached by past predators such as owls and other birds of prey. Fossils of this group are often used for biostratigraphic dating of archeological sites in North America and Europe.