The water voles are large voles in the genus Arvicola. They are found in both aquatic and dry habitat through Europe and much of northern Asia. A water vole found in Western North America was historically considered a member of this genus, but has been shown to be more closely related to members of the genus Microtus. Head and body lengths are 12–22 cm, tail lengths are 6.5–12.5 cm, and their weights are 70–250 g. The animals may exhibit indeterminate growth. They are thick-furred and have hairy fringes on their feet that improve their swimming ability.