Bank vole upper skull. Coloured scanning electron micrograph (SEM) of the upper skull of the bank vole (Clethrionomys glareolus), seen from underneath. Bank voles are native to Europe and Central Asia. The bank vole lives amongst woodland and grassland. It feeds on fruit, nuts and small insects, making nests underground or in and around trees. Bank voles grow to about 12 centimetres in length and live to an age of around 18 months. Magnification: x3 at 10cm wide.