Dipodidae Author Don E. Wilson Author Russell A. Mittermeier Author Thomas E. Lacher, Jr text 2017 2017-11-30 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 7 Rodents II 81 100 book chapter 60686 10.5281/zenodo.6591722 9d33d7df-dc06-426e-8945-d99b967af193 978-84-16728-04-6 6591722 12. Siberian Jerboa Orientallactaga sibirica French: Gerboise de Sibérie / German: Sibirien-Pferdespringer / Spanish: Jerbo de Siberia Other common names: Mongolian Five-toed Jerboa , Siberian Five-toed Jerboa Taxonomy. Yerbua sibirica Forster, 1778 , Torey Lakes , Zabaykalsky Krai , Russia . Phylogenetically, O. sibirica is the sister species of O. bullata . Genetic data provide some evidence that O. sibirica is not a single species but a complex of cryptic species; however, specific descriptions and distributions of these species are not yet clear. Nine subspecies recognized. Subspecies and Distribution. O.s.sibiricaForster,1778—SESiberia(BuryatiaandZabaykalskyKraiinRussia),N&NEMongolia,andNEChina(NEInnerMongolia[=NeiMongol],Heilongjiang,andJilin). O.s.altorumOgneyv,1946—SslopesofTianShaninSKyrgyzstanandWChina(SWXinjiang). O.s.bulganensisShenbrot,1991—DzungarianBasininNWChina(NXinjiang)andSWMongolia. O.s.dementiew:Toktosunov,1958—Issyk-KulLakeBasininNEKyrgyzstan. O.s.longiorG.S.Miller,1911—C&EChina(NfoothillsofTibetanPlateauinQinghai,Gansu,Ningxia,andSShaanxi,andHebei). O.s.ogneviShenbrot,1991—C&EKazakhstanEofSary-suRiver. O.s.rueckbeiliThomas,1914—IliBasininSEKazakhstan(AlmatyRegion). O.s.saltatorEversmann,1848—SSiberia(SAltaiandTuvainRussia),NW,C&SMongolia,andNChina(InnerMongolia,NShaanxi,NShanxi,andNLiaoning). O. s. suschkini Satunin, 1900 — SW Kazakhstan (W of Sary-su River), NW Uzbekistan, and N Turkmenistan. Descriptive notes. Head—body 124-180 mm, tail 174-240 mm, ear 36-52 mm, hindfoot 60-79 mm; weight 85-170 g. There is no significant secondary sexual dimorphism. Condylo-basal lengths of skulls are 30-9-39-6 mm, zygomatic breadths are 22— 28-6 mm, and maxillary tooth row lengths are 6-4-8-4 mm. Dorsum varies from dark brownish gray to light grayish sandy; top of head in some subspecies has same color as back, but in others,it is significantly lighter, ash-gray; sides and ventral pelage are pure white; tail banner is wide and well flattened, three-colored, with short (10-15 mm) white basal ring, long (30-45 mm) black subterminal field and short (20-25 mm) white terminal tuft; and ventral side of black subterminal field is dissected along tail rod by wide white stripe, with narrow black strip in middle ofit in some subspecies. Toes of hindfeet are covered from below with brushes of moderate long (5-7 mm) soft hairs, black or brown inside and white outside; conic calluses at bases oftoes are large but relatively low, with wide bases. Auditory bullae are weakly inflated. Mastoid cavity is extremely small and not subdivided into sections; tympanic cavity is medium-sized. Front surfaces of incisors are white; incisors are significantly deflected forward. P! is relatively large and about equal in diameter to M?. Molars are medium-crowned, with terraced masticatory surfaces; crown heights of unworn molars are 90-125% of their lengths. Glans penis is egg-shaped, 4:6-6-4 mm long and 3-2—4-5 mm wide, slightly compressed in dorso-ventral direction, subdivided by deep longitudinal dorsal fold into two lateral lobes; surfaces of lobes are covered by single-vertex, backward-directed aciculae increasing in size in backward direction; and aciculae are arranged in 8-10 concentric rows, with 14-16 aciculae in each row. Os penis (baculum) is absent. Chromosomal complement has 2n = 48 and FN = 96. Habitat. Forest steppe, plain and mountain steppes, semi-desert, and desert. The Siberian Jerboa lives in mountains up to elevations of ¢.3500 m. In forest steppe and steppe,it selects dry open areas with sparse grass cover on pastures, shores of salt lakes, high terraces of river valleys, and rocky hill slopes; in some areas, it occurs in open park forests of larch ( Larix , Pinaceae ). In semi-desert and desert, it occurs in almost all habitat types, preferring areas with sagebrush ( Artemisia spp. , Asteraceae ) and succulent dwarf shrubs ( Anabasis and Salsola , both Amaranthaceae ) on light sandy clay soils in western part ofits distribution and Stipa (Poaceae) and Allium (Amaryllidaceae) associations on gravelsoils in middle parts of foothill belts in eastern part ofits distribution. Food and Feeding. The Siberian Jerboa is omnivorous. Depending on region and season, its main foods are seeds, insects, and green or underground plant parts, but on average, these food are in equal amounts in its diet. The Siberian Jerboa is able to hunt and catch flying insects byjumping and catching them with forefeet. Breeding. Breeding of the Siberian Jerboa occurs in April-August. Litters have 1-7 young (average range 2-8-3-7). Overwintering females produce 1-2 litters/year. Sexual maturity occursafter the first overwintering. Young nurse for c.1-5 months. Activity patterns. Siberian Jerboas are crepuscular and nocturnal. Aboveground activity usually starts at twilight and ends immediately before sunrise. Hibernation lasts from September—November to April. Movements, Home range and Social organization. Siberian Jerboas move slowly when foraging, using bipedal pacing with alternating support by left and right hindfeet. When running fast, they use asynchronous ricochetjumps. Maximum speed is 9 m/s. Escape behavior is characterized by a fast run to hid inside dense vegetation; shelter burrows are used reluctantly. Home ranges are 2-5 ha—30 ha. Summer burrows usually consist of main tunnel, starting from main entrance at the ground surface and sloping down with one right-angled turn to the nest chamber. Entrance is usually closed with soil plug 15-20 cm long. Emergency exits are usually absent; burrows with 1-2 emergency exits are less common. Total lengths of tunnels are 70-560 cm, usually 150-300 cm; nest chamber is 10-15 cm in diameter and 35-65 cm deep. Winter burrows are longer and deeper than summer burrows; total length of tunnels in winter burrows is up to 6 m, and depth is 2:6 m. Night shelter burrows are simple, with one tunnel 80-160 cm long. One individual has 1-2 shelter burrows in its home range. Entrance of shelter burrow is very obvious because of the well-worn path leading to it. In the wild, Siberian Jerboas are solitary, but sometimes they are seen in groups of 2-3 individuals. Status and Conservation. Classified as Least Concern on The IUCN Red List (as Allactaga sibirica ). Bibliography. Pisano et al. (2015), Shenbrot et al. (2008), Sokolov, Lobachev & Orlov (1998), Zhang Yongzu et al. (1997).