116.

Sakhalin Vole

Alexandromys sachalinensis

French: Campagnol de Sakhaline / German: Sachalin-Wihlmaus / Spanish: Topillo de Sajalin

Other common names: Sakhalin Island Vole

Taxonomy. Microtus sachalinensis Vasin, 1955, Olen’ya River Estuary, Sakhalin Island, Russia.

Alexandromys sachalinensis is in subgenus Alexandromys and fortis species group. Morphologically and with analysis of nuclear genes, it is sister species to A. fortis; mtDNA suggests close relationship with A. maximowiczii . Monotypic.

Distribution. N & C parts of Sakhalin I, Russia.

Descriptive notes. Head—body 108-176 mm, tail 34-74 mm, ear 10-21 mm, hindfoot 17-26 mm; weight 30-149 g. Male Sakhalin Voles are larger than females. Fur on head and upperparts is reddish brown, underparts are whitish gray, and tail is sharply bicolored. Sole of foot has five plantar pads. M® has 4-5 (usually five) inner and 3-5 (usually five) outer angles. Baculum is medium-sized (4-5-2 mm long); its base is narrow, with right-angle or rounded proximal edge, and proximal base is 1-1-2-2 mm wide. Median processes are long (1-3-2 mm), and lateral one is medium-sized (0-6 1-2 mm). Chromosomal complement has 2n = 50 and FN = 64.

Habitat. Boreal coniferous forest zone. The Sakhalin Vole inhabits mainly shores and islands in peat moss bogs, but it is also found in salt marshes, meadows, and light forests.

Food and Feeding. The Sakhalin Vole mainly eats green parts of grasses and sedges, but it also eats forbs, shoots, bark of willows ( Salix, Salicaceae), and mollusks.

Breeding. Breeding of wild Sakhalin Voles was recorded in May-September. Litters have 1-15 young (average 9-2), and intervals between pregnancies are 17-92 days (average 29). Adult females have two (probably up to three) litters per year. Gestation lasts 17-20 days. Females born in the first half of summer produce one litter in the same season; those born in the end of summer are reproductively mature in the following spring.

Activity patterns. No information.

Movements, Home range and Social organization. The Sakhalin Vole lives in family colonies. All burrows, nests, and foraging sites of colony members are connected by pathways and tunnels. Nest burrows consist of a nest chamber (10-12 cm in diameter and 10-20 cm deep) and 1-3 storage chambers (c.35 cm in diameter).

Status and Conservation. Classified as Near Threatened on The IUCN Red List (as Microtus sachalinensis). The Sakhalin Vole is endemic to a single island, and it is threatened by habitat fragmentation from recent infrastructure development.

Bibliography. Abramson & Lissovsky (2012), Gromov & Erbajeva (1995), Haring et al. (2011), Kostenko (1984), Lissovsky & Obolenskaya (2011), Meyer et al. (1996).