78.

Northern Mole Vole

Ellobius talpinus

French: Campagnol taupe / German: Nordlicher Mull-Lemming / Spanish: Topillo topo septentrional

Taxonomy. Mus talpinus Pallas, 1770, between Kuibyshev (= Samara) and Kostytchi, W bank of Volga River, Russia.

Ellobius talpinus is in the subgenus Ellobius . In the past, E. talpinus also included E. tancrei . Taxonomic distinction between these two species was first retrieved from chromosomal evidence and subsequently confirmed by molecular data. They presumably diverged during Quaternary climatic cycles about one million years ago.

Four subspecies recognized.

Subspecies and Distribution.

E.t.talpinusPallas,1770—SEEuropeanRussia,SWSiberia,andpossiblyNKazakhstan.

E.t.rufescensEversmann,1850—WKazakhstan(betweenlowerUralandEmbarivers,andprobablydesertsWofAralSeaincludingNWUzbekistan).

E.t.tanaiticusZubko,1940—UkraineandSEuropeanRussiaasfarEasNWCaspianshoreandthelowerVolgaRiver.

E. t. transcaspiae Thomas, 1912 — Turkmenistan and NE Iran.

Descriptive notes. Head-body 84-115 mm, tail 8-21 mm; weight 24-56 g. Body of the Northern Mole Vole is cylindrical with large, blunt head, short neck, and heavy chest. Nose pad is large, ears vestigial, and eyes are minute (3-2 mm in diameter). Tail is shorter than hindfoot, densely covered with stiff hairs. Front feet are heavier than hindfeet. Thumb is not reduced to such a degree as in most rodent species. Claws are strong but short. Females have eight nipples: two pairs of abdominal and two pairs of inguinal. Furis velvety, and coloris extremely variable. Belly is normally lighter and grayish. Head is darker than back, frequently black between nose and ears. Lightest individuals have sandy brown back, light gray belly, and brown head. In contrast, blackish brown individuals have black heads or are completely black; they can have rusty blotches on head and rusty front legs. In most populations of Northern Mole Voles, back is either grayish brown, brown, fawn, or rusty brown; belly is gray, occasionally washed buff; and head is dark brown or black. Skull is fossorial, relatively wider than species in subgenus Afganomys; rostrum is shorter; incisive foramina are less reduced; interorbital region is flat and wide; and supratemporal ridges neverfuse into crest. Mandible is powerful, with prominent alveolar process. Incisors are long and markedly fossorial, with white front surfaces. Molars are rooted, with simple pattern of broadly confluent dental fields and without cement in reentrant loops.

Habitat. Forest steppe, steppe, and semi-deserts on chernozem (black-colored, humusrich) soil, clay, sand, and even gravelly or stony substrate. Northern Mole Voles are sensitive to freezing of soil during winter in northern borders of the distribution, and deep snow cover can be crucial for winter survival. During dry summers, they migrate from steppic habitats into birch ( Betula, Betulaceae) stands.

Food and Feeding. Northern Mole Voles consume up to 59-67 g of food/ day . Diet consists of underground parts (i.e. bulbs ofiris and garlic) and grass roots. Feeding tunnels are 15-20 cm deep in Turkmenistan. Feeding on the ground’s surface becomes more frequent in autumn and during reproduction. Food is not cached.

Breeding. Reproduction starts in late winter and early spring and peaks in February— March. Females have 1-2 litters/year, but some authors have reported 3-4 litters/year. Mean litter sizes are 3-1-4-9 and vary among populations; overall mean for the species is four young (range 1-7). Gestation is 30 days. Newborns weight 3 g and are naked and blind. Eyes open at 21-28 days old, and young start eating solid food at 20-25 days old. Juveniles enter the population in April-May, rarely in March or June; they weight c.40 g at two months old. Females may reproduce during first year but more frequently are sexually mature in their second year. Life expectancy is two years.

Activity patterns. Northern Mole Voles are active day and night, with peaks in morning and evening. Activity is reduced in winter and during summer droughts, and individuals can undergo lethargic periods. Northern Mole Voles are strictly fossorial. They rarely emerge from burrows and only at night. Digging activity goes on yearround, with peaks in spring and autumn. Speed of digging through soil averages 10-2 cm/minute. Digging is performed by two or more individuals. The first one digs with its incisors, and helpers behind push excavated dirt to the ground’s surface; positions are rotated. Amount of soil excavated annually is estimated at 2-3 m’/family group. Entrances to a burrow system are sealed with elliptically shaped mounds of soil, 13-68 cm long, 10-38 cm wide, and 2-10 cm high. There are 20-35 heaps/ family group, and excavated soil can cover 20-23% of the ground’s surface. Nest chamberis 11 x 11 x 9 cm and 40-65 cm deep in Turkmenistan but deeper (1-4 m) in the north. Old nest chambers are plugged with soil. In hot days and after heavy rains, Northern Mole Voles unplug burrows for ventilation. Tunnels are 5-6 cm in diameter (mean 5-2 cm).

Movements, Home range and Social organization. The Northern Mole Vole is colonial, with family groups spaced 200-300 m apart. Burrow systems are dug out and maintained by a family of up to ten individuals. Only one female is reproductively active in a family. In Turkmenistan, postnatal dispersion is in March—-May. Young move up to 800 m away from natal burrows.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Populations of Northern Mole Voles on western edge of the distribution are declining. Entire population in Ukraine is believed to be 2000-3000 individuals, and it is extirpated on lower parts of the Dnieper River.

Bibliography. Bogdanov et al. (2015), Evdokimov (2001), Gromov & Erbajeva (1995), Korobchenko & Kondratenko (2009), Marinina (2005b), Popov (1960), Shenbrot & Krasnov (2005), Shlyakhtin et al. (2009), Vorontsov & Yakimenko (1984).