Smith's Vole

Smith's Vole
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Cricetidae
Genus:	Myodes
Species:	M. smithii
Binomial name
Myodes smithii (Thomas, 1905)
Synonyms
Eothenomys smithii (Thomas, 1905) Phaulomys smithii (Thomas, 1905) [2]

Smith's vole (Myodes smithii) is a species of rodent in the family Cricetidae. It is also known as Smith's red-backed vole and is found only in Japan.

This vole is named after Richard Gordon Smith, (1858–1918) who, after falling out with his wife, traveled the world hunting for animals and keeping a record of his travels and discoveries in eight large leather-bound diaries. He spent some time in Japan where he collected mammals for the British Museum,^[3] including the type species of this vole.^[4]

Taxonomy

There has been considerable discussion as to the phylogeny of this species. The molars grow continually during the animal's life and because of this trait, it was at one time placed in the genus Phaulomys. However, studies using mitochondrial and nuclear ribosomal DNA have shown that it is closely related to the Japanese and Asian species, Myodes rufocanus, and the Korean species, Myodes regulus and that there is no support for its inclusion in Phaulomys. The ever-growing molars in M smithii are now believed to be independently derived from a rooted Myodes ancestor endemic to Japan.^[5]

Distribution

Smith's vole is found on the Japanese islands of Dogo, Honshu, Kyushu and Shikoku.^[5] Also at Oki and four cities and one town in the region of Mikawa.^[6]

Description

The colour of Smith's vole varies from brownish-yellow to mid brown with the underparts a paler shade of brown. The body length is about 115 millimetres with a tail about 60 millimetres. The weight varies between 20 and 35 grams. The fur is dense and short, the muzzle blunt and the ears rounded. The dental formula is $Upper: 1.0.0.3, lower: 1.0.0.3$ and the molars grow continuously throughout life.^[6]

Ecology

Smith's vole lives in forests, plantations and farmland in montane areas above about 400 metres. It is absent from alluvial plains. It makes burrows in leaf litter and prefers damp conditions. It is a common species in chosen habitat but some of its populations are fragmented by road development, land reclamation, dam building and deforestation. The diet is entirely vegetarian and it feeds on the stems and leaves of green plants and on seeds. The breeding season varies in different locations and there may be one or two litters per year, each of one to six young, but usually two or three.^[6]

References

1. ^ Kaneko, Y. & Ishii, N. (2008). Myodes smithii. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 30 June 2009. Database entry includes a brief justification of why this species is of least concern.
2. ^ IUCN Red List
3. ^ Richard Gordon Smith's Journal
4. ^ The Eponym Dictionary of Mammals
5. ^ ^{a b} Mammal Species of the World
6. ^ ^{a b c} Mammals of Japan

• Musser, G. G. and M. D. Carleton. 2005. Superfamily Muroidea. pp. 894–1531 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.