Kingdom	Animalia	Animals
Phylum	Chordata	Animals with a notochord
Sub-phylum	Vertebrata	Animals with a backbone
Class	Mammalia	Animals which suckle their young on milk
Sub-class	Theria	Mammals that develop inside their mother rather than an egg
Infra-class	Eutheria	Mammals with a placenta
Order	Rodentia	Mammals with chisel-like incisors
Sub-order	Myomorpha	Mouse-like rodents
Family	Cricetidae	Hamsters, deer mice, lemmings, musk rats, gerbils, voles.
Genus	Microtus	Typical voles with open-rooted teeth.
Species	Microtus arvalis	Common vole
Sub-species	Microtus arvalis orcadensis	Orkney vole