83.

Yellow Steppe Lemming

Eolagurus luteus

French: Campagnol jaune / German: Gelblemming / Spanish: Lemming de estepa dorado

Taxonomy. Georychus luteus Eversmann, 1840, NW of Aral Sea, Kyzylorda Region, Kazakhstan.

Some authors have considered luteus to be a member of genus Lagurus . Monotypic.

Distribution. Extreme E Kazakhstan (E Zaysan Depression), China (Dzungarian Basin in N Xinjiang), and SW Mongolia (Dzungarian Gobi).

Descriptive notes. Head-body 130-162 mm, tail 14-23 mm, ear 4-7 mm, hindfoot 17-22 mm; weight 60-140 g. Fur color of head and upperparts is light grayish sandy-yellow; underparts are light pale or yellowish clay; tail is uniformly light, whitish. There are four plantar pads. Claw offirst pollex is small, with pointed end. Auditory bullae are large and inflated but not projected backward from level of condylus occipitalis. M? has two inner and three outer angles. M, has seven partially isolated dentine areas on its masticatory surface; its anterior loop lacks additional angles and is isolated from antero-lingual triangle. Chromosomal complement has 2n = 56 and FN = 58.

Habitat. Semi-desert and desert at elevations up to 2100 m. The Yellow Steppe Lemming occupies areas with clay or sandy soils and sparse shrubs ( Artemisia, Asteraceae, and Krascheninnikovia, Amaranthaceae) and grasses, preferring depressions ofrelief.

Food and Feeding. Diets of Yellow Steppe Lemmings contain green plant parts and seeds in autumn but in relatively small amounts. They do not store winter food.

Breeding. Reproductive period of the Yellow Steppe Lemming occur in April-September. Litters have 2-11 young (average 4-6-8-5). Adult females can produce 2 litters/ year. Females become sexually mature at ¢.20-25 days and can produce one litter in the year of their birth.

Activity patterns. Yellow Steppe Lemmings are active round-the-clock. In spring and autumn, activity is mainly diurnal, but in summer, it is nocturnal and crepuscular.

Movements, Home range and Social organization. In spring, summer, and autumn, Yellow Steppe Lemmings live in monogamous family groups. At the beginning of breeding season, the family group usually consists of a male and a female and later includes immature yearlings from 1-2 generations. Yearlings reach sexual maturity after they disperse from parents’ burrow. Each family group occupies one burrow. Contacts between individuals, especially from different family groups, are usually aggressive. Burrow has a nest chamber, 18-20 cm in diameter and 40-80 cm deep, and a complex system of tunnels at depths of 20-25 cm; burrow covers surface area of 200-400 m?; there are 50-60 entrances that are 0-5-3 m (usually 1-5-2 m) from one another. In winter, Yellow Steppe Lemmings live individually under snow in aboveground spherical nests made of dry plant material, 20-25 cm in diameter with 1-2 entrances and 2—4cm thick walls. Contacts among individuals are accompanied by acoustic communication expressed in quiet and sharp squeals emitted by both sexes.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Yellow Steppe Lemming became extinct in western Kazakhstan (between Caspian and Aral Seas) in 19" century and in central Kazakhstan in mid-20" century.

Bibliography. Bannikov (1954), Gromov & Erbajeva (1995), Ma Yong et al. (1982), Ognev (1950), Rutovskaya (2015), Sludskiy et al. (1978), Sokolov & Orlov (1980), Zhang Yongzu et al. (1997).