46.

Smith’s Red-backed Vole

Craseomys smithii

French: Campagnol de Smith / German: Smith-Graurételmaus / Spanish: Topillo rojo de Smith

Other common names: Smith's Vole

Taxonomy. Evotomys (Phaulomys) smithii Thomas, 1905, Kobe, Hyogo Prefecture, Honshu, Japan.

Craseomys smithit is closely related to C. andersoni. Molecular and chromosomal studies retrieved limited past introgression between C. andersoni and C. smithii . Craseomys smithi has been classified as Clethrionoyms, Myodes, Phaulomys, Aschizomys, or Eothenomys . Japanese authorsstill retain it in Eothenomys . Monotypic.

Distribution. Endemic to Japan (C & S Honshu, Shikoku, and Kyushu).

Descriptive notes. Head—body 70-117 mm, tail 30-50 mm; weight 20-35 g. Smith’s Redbacked Vole is small, with tail accounting for 40-50% of head-body length. Females have four, five, or six nipples. Pelage is rusty brown or yellowish brown on dorsal side and light yellow on belly. Skull is delicate and rounded, and molar pattern is smoothed. Molars remain rootless throughoutlife.

Habitat. Mesic sites in natural forests and forest plantations but also agricultural areas and rocky situations at elevations of 60-2400 m. Smith’s Red-backed Vole occupies lower elevations where Anderson’s Red-backed Vole (C. andersoni) is also present.

Food and Feeding. Smith’s Red-backed Vole is less of a leaf-eater than Anderson’s Redbacked Vole. Fruits and seeds are important in its diet, particularly berries and tree nuts (acorns and chestnuts).

Breeding. Breeding season of Smith’s Red-backed Vole is in March—November, with great variation depending on latitude and elevation. Breeding season is truncated to May—October at a elevation of 600 m and June-September at 1000 m. Vaginas of captive females begin to perforate at 23-28 days old, and youngest age of parturition is 120 days. Gestation lasts 19 days. Mean litter sizes vary among populations from 2-1 to 4-1 young. Captive individuals can live more than three years.

Activity patterns. Captive Smith’s Red-backed Voles display polyphasic activity, with 2-3 peaks during the day .

Movements, Home range and Social organization. Home-ranges are 0-06-0-10 ha and 23-1-25-7 m long.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as Myodes smithat). Overall distribution size of Smith’s Red-backed Vole is ¢.166,000 km?.

Bibliography. Kaneko & Iwasa (2015), Tabata & Iwasa (2013).