91.

European Snow Vole

Chionomys nivalis

French: Campagnol des neiges / German: Schneemaus / Spanish: Topillo nival europeo

Other common names: Snow Vole

Taxonomy. Arvicola nivalis Martins, 1842, Faulhorn, Bernese Oberland, Switzerland.

Chionomys nivalis is in the nivalis species group. In the past, C. nivalis was included in the genus Microtus . Taxonomic status of C. lay: taxon named by A. E. Zykov in 2004 from Zagros Mountains, Iran, is not known. Subsequent list of subspecies is tentative. Subspecies can be arranged into two groups, nivalis group with all subspecies except dementievi, which is in a group on its own (dementievi group). Thirteen subspecies recognized.

Subspecies and Distribution.

n. nivalis Martins, 1842 — Alps. OOND no. abulensis Morales, 1936 — Iberian Peninsula.. aleco Paspalev, V. Martino & Pesheyv, 1952 — E Balkan Peninsula. 9. appenninicus Dal Piaz, 1929 — Italian Peninsula.. cedrorum Spitzenberger, 1973 — Taurus Mts and SW Anatolia, Turkey. 3. dementievi Heptner, 1939 — S Turkmenistan and NE Iran.. hermonis G. S. Miller, 1908 — Lebanon, W & S Syria, and extreme N Israel. OAD Ss. malyi Bolkay, 1925 — W Balkan Peninsula.. mirhanreini Schafer, 1935 — Tatra Mts in S Poland and Slovakia.. olympus Neuhauser, 1936 — NW Anatolia, N Turkey. 83 £. pontius G. S. Miller, 1908 — NE Anatolia, NE Turkey. n. trialeticus Shidlovsky, 1919 — Caucasus. C. n. ulpius G. S. Miller, 1908 — E & S Carpathian Mts in SW Ukraine and Romania. Also present in S France, S Turkey (Hatay Province), and NW Iran, but subspecies involved not known.

Descriptive notes. Head-body 107-143 mm, tail 40-75 mm; weight 29-5-62 g. The European Snow Vole closely resembles the Gudaur Snow Vole (C. gud), but it is considerably more variable in size, relative tail length, color, and craniodental morphology. Significant variation is in response to narrow local conditions, and neighboring populations can look quite different. Some populations are short-tailed, and others have relatively long tails. European Snow Voles from humid regions tend to be darker (dark brown back and dull gray belly), and those from arid regions are paler (light buffy back and grayish white belly). Various intermediate color types are known. Fur is soft and long. Guard hairs are thicker than in other arvicolines; diameter of shaft is 13— 16 pm, and diameter ofshield is 35-45 pm. Skull of the European Snow Vole is similar to that of the Gudaur Snow Vole, exceptit is deeper and has larger bullae. Compared with the Gudaur Snow Vole, M* of the European Snow Vole tends to have simpler morphology and is narrower posteriorly; typically, there are three inner salient angles.

Habitat. Rocky substrates, specifically in fissures and cracks with stable temperature and high humidity. Despite habitats of accumulated rocks, cliffs, and escarpments that are naturally fragmented into “continental archipelagos” being more common at higher elevations, European Snow Voles are found at elevations of 30-4700 m. Although they penetrate deep into forests as long as suitable rocky substrate is available, they prefer sites with grasses and sparse vegetation.

Food and Feeding. The European Snow Vole eats leaves, stems, flowers, seeds, and roots. Most frequently eaten include hawkweed ( Hieracium silvestre), Alpine coltsfoot ( Homogyne alpina), hawksbeards ( Crepis blattarioides and C. aurea), Clavena’s yarrow ( Achillea clavennae), and thistle ( Cirsium), all Asteraceae; bluegrass ( Poa annua and P. chaixii), tufted hairgrass ( Deschampsia cespitosa), red fescue ( Festuca rubra), and reed grass ( Calamagrostis arundinacea), all Poaceae; spreading bellflower ( Campanula abietina, Campanulaceae); myrtle blueberry ( Vaccinium myrtillus, Ericaceae); strawberry ( Fragaria vesca) and dwarf yellow cinquefoil ( Potentilla aurea), both Rosaceae; sedge Carex sempervirens (Cyperaceae); red clover ( Trifolium pratense) and bird’s-foot trefoil ( Lotus corniculatus), both Fabaceae . Mosses and lichens can be an important dietary component. Mean daily intake is 51-9 g of fresh matter, corresponding to 8-1 g of dry matter. Daily energy budget does not depend on season. The European Snow Vole hoards, dries, and stores plants for winter use. Caches are gathered under rocks and in fissures where they are protected from rain. It is also reported that burrows contain one or more caches.

Breeding. Breeding season coincides with snow-free period. Gravid females were collected in March—-November, with considerable variation among regions. In general, breeding season is shorter as elevation increases. Gestation lasts 20-22 days. Females in early litters can become sexually mature and reproduce before their first winter, but breeding activity of males is postponed until the next season. Females normally have 2 litters/season, although some authors report third and even fourth litters. Numbers of embryos are 2-6/female, with means of 3-3-3 in the Alps and 4-1 in Anatolia. Litters have 1-4 young. Newborns weight 3-2-4 g. Eyes open at 13 days old, and youngstart to leave nests at 2-3 weeks old. About 33% of young die before weaning. Survival rate of females is high, and maximum observed life span is 36 months.

Activity patterns. Captive European Snow Voles showed polyphasic activity, with main peak during night and another one at ¢.14:00 h. Observations in the wild demonstrated plasticity in activity. European Snow Voles can be crepuscular yearround, nocturnal mainly in summer, and diurnal in winter. They find shelter among rocks. Opinions on whether they dig at all are contradictory. Nesting chamber is lined with dry grass.

Movements, Home range and Social organization. European Snow Voles walk, run, and climb. When out of the nest, they try to stay sheltered in rocks. Adult males have larger home ranges (mean 332 m?) than adult females (207 m?) and immature individuals (104 m*). Home ranges are fairly stable and independent of season or density. Female home ranges do not overlap, but male home ranges overlap with several female home ranges. Home ranges are marked with urine and feces. European Snow Voles are reported to be docile.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Janeau & Aulagnier (1997), Krapp (1982a), Kratochvil (1981), Krystufek & Kovaci¢ (1989), KryStufek & Vohralik (2005), Krystufek, Klenovsek et al. (2015), Martirosjan (1970), Nadachowski (1991), Yannic et al. (2012), Zykov (2004).