5.

Ciscaucasian Hamster

Mesocricetus radder

French: Hamster du Daghestan / German: Schwarzbrusthamster / Spanish: Hamster del Caucaso

Taxonomy. Cricetus nigricans radder Nehring, 1894, Samur River, Dagestan, N Caucasus, Russia.

In the past, M. raddei was synonymized with M. auratus, but they are sister species and share identical karyotype (2n = 44) but differ in morphology and nucleotide sequences. Includes nigriculus as a junior synonym of the nominate subspecies. Two subspecies recognized.

Subspecies and Distribution.

M.r.radde:Nehring,1894—mostofrangebetweenthelowerreachesofDonRiverandSDagestan(Russia),includingasinglerecordinextremeNEGeorgia.

M. r. avaricus Ognev & Heptner, 1927 — C Dagestan Plateau.

Descriptive notes. Head-body 149-220 mm, tail 12-20 mm; weight 200-300 g. General form and proportions of the Ciscaucasian Hamster are like those of the Golden Hamster ( M. auratus), but pelage lacks reddish tints. Back is gray, only rarely washed buff, and flanks and belly are dirt white, gray, or blackish gray. Transverse band on chest is black and extensive, blotch on cheeks and shoulder is cream, and oblique sub-auricularstripe is blackish brown or black. Black and white individuals were found in the wild. Skull resembles that of the Golden Hamster exceptit is more ridged with more robust rostrum. Molars show no peculiarities.

Habitat. Grass and grass-herb steppes, xeric mountain steppes, and fallow land at elevations of 200-2800 m. Although Ciscaucasian Hamsters prefer natural habitats, they also occupy arable land and are occasionally found in woodlands within steppes.

Food and Feeding. Green plants are staples in spring and early summer diets of Ciscaucasian Hamsters; seeds, roots, and tubers dominate autumn diets. They carry seeds in expandable cheek pouches into burrows for winter caches of 16 kg or more. They are considered an important agricultural pest.

Breeding. Main reproductive period of the Ciscaucasian Hamster is spring and early summer, depending on elevation. Females have 2 litters/year at high elevations and 3 litters/year at low elevations; fourlitters are exceptional. There are 4-20 young/litter (average twelve).

Activity patterns. The Ciscaucasian Hamster is crepuscular and nocturnal but also diurnal in spring and summer. It hibernates in October-March. It is an active digger; digging activity peaks during postnatal dispersion in May-July. Burrow entrances have diameters of 5-7 cm for adults and 4.5-5 cm for young. Initial vertical shafts of 40-100 cm continue into 50-80 cm long horizontal tunnels that may branch further into galleries and chambers used for food storage, latrines, and nesting.

Movements, Home range and Social organization. Male Ciscaucasian Hamsters are aggressive among themselves, producing teeth chattering in antagonistic encounters.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Densities are high (up to 39-96 ind/ha), and no major threats have been reported. In Rostov Oblast, Russia, the Ciscaucasian Hamster is expanding northward and westward. Nevertheless, it is included in red books of Satvropol Krai and Kalmykia Republic. Populations declines in Kalmykia have been noted since the 1960s.

Bibliography. Lebedev (2012), Likhovid (2002), Neumann et al. (2006), Romanenko et al. (2007), Sandzhiev et al. (2013), Tembotov (1965, 1972).