Animal Diversity Web

Geographic Range

The native geographic range of russet ground squirrels (Spermophilus major) encompasses the Trans-Volga region of Russia, and northern Kazakhstan. In Russia, they primarily inhabit the region between the Volga and Irtysh rivers, and in Kazakhstan they live in the northern clay Caspian semi-desert and northern Trans-Urals. The northern Trans-Urals includes the northern semidried near-floodplain region and the Ilekskii dry-steppe region. (Helgen, et al., 2009; Okulova, et al., 2014; Rumyantsev, et al., 2012)

Russet ground squirrels have been introduced to new regions in Russia by humans. In 1988, 15 females and 15 males from the Saratov oblast were released east of the Mastinovka village. They acclimatized successfully, and began actively occupying nearby areas. They had spread 20 km to the north, 40 km to the west, and 7 km to the east of the release point by 2010. A stable population center of russet ground squirrels thus formed 140 km west of the closest natural colonies (Ul’yanovsk oblast, Nikolaevka district; Russia). Due to suitable nearby habitat, this introduced population is expected to spread to the Penza oblast. In addition, russet ground squirrels have been introduced to the northern Caucasus Mountains in Russia. (Rumyantsev, et al., 2012; Thorington, et al., 2012)

Since the 1950s, russet ground squirrels have expanded their geographic range southward. The southern border was originally just southeast of the Bolshoy Irgiz river (Russia), where it was outside the bounds of the dry bunchgrass steppes. By the beginning of the 21st century they had expanded well into the dry bunchgrass steppes territory, and approached the desert steppes subzone in the Novouzensk, Piter, and Krasnokutsk regions of Russia.

In a similar area, on the east side of the Volga river in the Volga-Ural steppes, the southern border expanded southward by approximately 100 km between the 1970s to 2000s along the Volga river with an average speed of advancement of 3.3 km per year. While in eastern Saratov, the southern border shifted 50-60 km south at a slower rate at about 2 km per year. In addition, the population in the west was expanding between the 1970s and 2000, and was predicted to continue expanding. These expansions were attributed to the warming and humidification of climate in the temperate latitudes, and the anthropogenic transformation of landscapes such as road construction and the rerouting of water sources. (Ermakov and Titov, 2000; Oparin and Oparina, 2009)

• Biogeographic Regions
• palearctic
  • introduced
  • native

Habitat

Russet ground squirrels are considered meadow ground squirrels, and are generally found in steppe habitat with loamy soil. The steppe types they usually inhabit are northern forb (e.g. Potentilla bifurca and Lepidium ruderale), feather grass (Stipa spp.), graminoid-forb (e.g. Eremopyrum triticeum, Poa bulbosa, and Descurainia sophia), and worm-wood-sheep fescue (e.g. Artemisia spp. and Festuca spp.) steppes. Russet ground squirrels can be found in non-flooded meadows, forest edges, and river valleys, and also in human disturbed areas such as abandoned settlements, roadside verges, pastures, road earth mounds, and farmlands.

Russet ground squirrels have a versatile biotope niche where they can settle in mesophytic moderately grassed, sandy and wet biotopes with gramineous-forb associations, and also in biotopes with tall and ruderal vegetation (e.g. Atriplex tatarica and Ambrosia artemisiifolia). The colonies are associated with complex diverse vegetation mosaics. However, their most preferred habitats are mesophytic graminoid rich meadows.

Interestingly, in a symptaric zone with speckled ground squirrels (Spermophilus suslicus) in the Ul'yanovsk oblast (Russia), russet ground squirrels show preference for xerophytic habitats instead of mesophytic ones. In general, it appears russet ground squirrels inhabit different biotopes when in mixed colonies such as with S. suslicus and yellow ground squirrels Spermophilus fulvus than when they are in their single species colonies.

Russet ground squirrels use bands of steppe adjacent to roadsides and forest belt edges as outposts, and anthropogenic affected regions such as periodically inundated pond banks and small steppe river floodplains as supplementary dispersal channels for their southward range expansion. Anthropogenic examples include the pumping of water from the Volga river into smaller rivers via supply canals, which in turn increased the area covered with meadow vegetation in the small river floodplains.

Russet ground squirrels are a lowland species, but there are records of them at elevations of 500 and 600 m. (Kryštufek and Vohralík, 2012; Ognev, 1947; Thorington, et al., 2012; Titov, 2000; Titov, et al., 2012)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• mountains

• Other Habitat Features
• agricultural

• Range elevation

  500-600 (high) m

  ft

Physical Description

Russet ground squirrels are relatively large ground squirrels with a head and body length up to 340 mm. Russet ground squirrels differ in pelage coloration between their back and belly; the back is a dark brown ochre that is often speckled with either light tawny or white spots, while the stomach varies from whitish to ochre. The fur along their sides ranges from rust to ochre color. Their tails are brown ochre on the top and reddish underneath. The top of head is frequently a silver gray color, while the snout is rusty colored. They have distinct rusty spots above and below their eyes and around their ears, with the rusty spots beneath their eyes being the most pronounced. Their hind feet soles are hairless except for their heels. Juvenile russet susliks have duller and grayer fur than the adults, and generally have no speckling on their backs. Their backs and sides are a gray-tinged yellow color, but the back may occasionally have slight pinkish buff markings, and the sides are bordered dorsally and ventrally with dull rusty hairs with white tips. Their bellies are a light gray color with yellow-tinged hairs. Similar to the adults, the juveniles have the intense rusty spots above and below their eyes.

Adult molt for russet ground squirrels occurs between late May and July. The molt begins on top of the spine, and gradually works its way towards the sides and back. By July, the trunk will have nearly finished its molt. Only the long light winter hairs on the sides are left to be molted.

There is some geographic variation observed in the species. Russet ground squirrels in mesic habitats along the Kama and Volga rivers (e.g. Samara, Russia) are larger (CbL = 54.1 mm) and darker, and in more arid habitats of the Orsk and Orenburg regions (Russia), they are paler and smaller (mean CbL = 49.7 mm). Russet ground squirrels also have seasonal variation in pelage. In winter, their fur is denser than in the summer, and the fur on their backs and stomachs becomes grayer.

Skulls of russet ground squirrels show no pecularities for the genus Spermophilus. Their brain-case is squarish, where it is wider than long or similar in length and breadth. Their zygomatic arches are moderately expanded, where the zygomatic arch breadth is 66 to 75 % of condylobasal length. The interorbital region is relatively narrow to the skull (interorbital width is less than 11 mm), and their auditory bullae are broader than long. Their mesopterygoid fossa is wide, and the margin of the hard palate is shifted well behind the M3s. The nasals expand posteriorly to the maxillary-frontal suture. Their maxillary tooth-row (alveolar) is less than 13.5 mm. Lastly, their anterior malleal process is reduced, and the expanded caput of the malleaus is slightly elevated.

The teeth of russet ground squirrels do not deviate from the general condition of the genus Spermophilus. The dental formula is 1/1, 0/0, 2/1, 3/3 = 22. The upper incisors have whitish to pale-yellow enamel. The cheek teeth are relatively hypsodont, with the upper row teeth having a triangular appearance due to their lingual region being constricted. The maxillary cheek teeth are shorter than their diastema. Lastly, the P4s are relatively small.

Female russet ground squirrels have 14 to 16 nipples, and in rare cases have 12 nipples. Lastly, they have the karyotype of 2n = 36. (Kryštufek and Vohralík, 2012; Ognev, 1947; Thorington, et al., 2012)

There are several related ground squirrel species that co-occur with Spermophilus major such as yellow ground squirrels (Spermophilus fulvus), red-cheeked ground squirrels (Spermophilus erythrogenys), speckled ground squirrels (Spermophilus suslicus), Brandt's ground squirrels (Spermophilus brevicauda), and little ground squirrels (Spermophilus pygmaeus). Russet ground squirrels can be differentiated from the yellow, speckled, Brandt's, and little ground squirrels by their dark conspicuous red spots under their eyes. These related ground squirrel species lack the rust spots on their faces. Russet ground squirrels can be told apart from red-cheeked ground squirrels by their smaller facial red spots and yellower faces. The large facial red spots of red-cheeked ground squirrels contrasts sharply with their whiter faces. In addition, if comparing females of these two species, female red-cheeked ground squirrels have 10-12 nipples, while female russet ground squirrels usually have 14-16 nipples.

Spermophilus major has been observed to hybridize with S. fulvus, S. erythrogenys, S. suslicus, S. pygmaeus and S. brevicauda when they occur sympatrically. (Helgen, et al., 2009; Kryštufek and Vohralík, 2012; Nikolsky and Starikov, 1997; Shmyrov, et al., 2011; Shmyrov, et al., 2012; Spiridonova, et al., 2005; Spiridonova, et al., 2006; Thorington, et al., 2012; Titov, 2000; Titov, et al., 2012)

Russet ground squirrels are sexually dimorphic; the males are larger than the females. Below is a summary of measurements for adult russet ground squirrels from different sources. There is some variation in measurements between the studies.

The average adult head and body length (HbL) is 275 mm with a range of 253 to 320 mm; the average tail length (TL) is 83.1 mm with a range of 73 to 105 mm; and the average hindfoot length (HfL) is 46.8 mm with a range of 42 to 52 mm. Skull measurments: the average total skull length is 54.23 mm with a range of 50.2 to 58.9 mm; the average condylobasal length of skull (CbL) is 52.04 mm and ranges from 47.6 to 56.3 mm; the average beadth across zygomatic arches (ZgB) is 37 mm and ranges from 33.9 to 41.0 mm; and the average temporal width is 23.19 mm with a range of 21.2 to 24.5 mm. Region and sex were not specified.

The average male HbL and TL is 268.7 mm and 83.7 mm respectively. The smaller female has an average HbL and TL of 260.4 mm and 81.0 mm respectively. For individuals of unknown sex, HbL is 281.0 mm and TL is 87.7 mm. Region was not specified.

The average HbL is 260 mm with a mass of 537 g. The sex and region were not specified.

In the Volga-Kama region - Russia*: The HbL ranges from 246 to 340 mm; TL ranges from 55 to 134 mm; HfL ranges from 33.0 to 56.0 mm; ear length ranges from 4.5 to 10.0 mm; and mass ranges from 287 to 570 g. The mass before hibernation can be as great as 1106 g and 1386 g for females and males respectively. Skull measurements: the CbL ranges from 47.6 to 59.8 mm; the ZgB ranges from 32.3 to 40.1 mm; and the maxillary tooth-row (alveolar) length (MxT) from 11.3 to 13.5 mm.

In the Samara region - Russia*:The average male HbL is 292 mm with a range of 253 to 314 mm; average TL is 73 mm with a range of 57 to 88 mm; average HfL is 48 mm with a range of 43 to 52 mm; average CbL is 54.3 mm with a range of 50.3 to 57.0 mm; and the average ZgB is 39.0 mm with a range of 36.0 to 41.5 mm. In contrast, the average female HbL is 280 mm with a range of 243 to 316 mm; average TL is 66 mm with a range of 53 to 81 mm; average HfL is 45 mm with a range of 32 to 48 mm; average CbL is 51.9 mm with a range of 50.0 to 54.3 mm; and the average ZgB is 37.5 mm with a range of 36.0 to 39.4 mm.

The adult mass ranges between 500 and 570 g. (Hayssen, 2008a; Hayssen, 2008b; Kryštufek and Vohralík, 2012; Matějů and Kratochvíl, 2013; Ognev, 1947; Thorington, et al., 2012)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  287 to 570 g

  10.11 to 20.09 oz

• Range length

  243 to 340 mm

  9.57 to 13.39 in

• Average length

  275 mm

  10.83 in

Reproduction

Russet ground squirrels are polygynous. Males have large territories (0.75 ha) that contain high concentrations of mobile females with much smaller territories (0.03 ha). The population ratio of males to females is often 1:6 or 1:7. The small territories of females results in eachfemales only mating with a single male. It has been observed that females only have one estrus during the breeding season each year.

There is some male-male competition for mates. Aggressive behavior is observed more frequently during the breeding season for both sexes most likely because of their territoriality. Males emerge from hibernation before females, where they then begin to mark their territory. They dig a ≈ 5 cm diameter hole next to their burrow where they clear away the snow, and mark the ground by cheek rubbing and urine. Females emerge later, once the snow has melted. The emergence of the females marks the beginning of the breeding season.

The direction of reproductive interactions between male and female russet ground squirrels is dependent on the readiness of the females to copulate and their behavior during their contacts. There are three main reproductive interactions: (1) if the female is alert on two or four paws on the ground and is tense during nasal - nasal interactions, the interactions leads to agnostic behaviors; (2) if the contact is a nasal - anal interaction (male and female respectively) interaction often leads to reproductive behaviors; and (3) if contact is an approach of both individuals approach towards each other, the interaction usually leads to neutral behaviors (e.g. grooming).

In general, if the female is not ready to mate, the male marks the territory and leaves her alone, and if the female is aggressive, the male engages in non-reproductive behaviors. When the female is close to estrus, she becomes more submissive and receptive to the male's advances, and after the estrous period is over, she again becomes aggressive to the male (e.g. fighting, biting, and boxing).

Copulation occurs in the burrows of the females, and lasts for approximately 10 to 15 minutes. After copulation, the males appears first from the female's burrow, and runs a few meters away from the burrow, then grooms upper body first then the genital area. Before he leaves the female territory, he often actively marks the territory. Several minutes after the male appeared from the burrow, the female emerges. She stays close to the entrance and grooms herself. After grooming she will then begin non-reproductive behaviors such as feeding and marking burrows.

Interestingly, russet ground squirrels are panmictic (i.e. assortative crossing absent) in hybrid settlements with yellow ground squirrels (S. fulvus). In these hybrid colonies, both male and female russet ground squirrels have been observed to have multiple matings with the hybrids, resulting in heterospermic broods. Female russet ground squirrels in these hybrid colonies are polyandrous. While in contrast, female russet ground squirrels in single species colonies only have the one mate (behaviorally monogamous), and thus do not have litters with multiple paternity. The males in both situations are polygynous. (Shmyrov, et al., 2011; Titov, 2004)

• Mating System
• polygynous

Breeding season begins as soon as the animals emerge from hibernation which occurs in April and May. Males emerge before the females, and they exhibit excited behaviors and enlargement of testes when the females finally awaken.

The females only have one litter per year. Average litter size is between 7 to 8 young, but litter sizes up to 16 young have been observed. The average little size for the Old World clade of genus Spermophilus is 6.19 young with a range of 4.6 to 8.0.

Gestation period for this species is not known, however for the Old World clade of genus Spermophilus, the gestation period occurs for 28.4 days on average with a range of 23 to 31 days.

Lactation period lasts for 2 months (≈60 days), with the weaning mass of approximately 200 g. In comparison, the lactation period was found to be an average of 39.6 days with a range of 29 to 60 days for the Old World clade of genus Spermophilus.

The young are born in spring in the burrow, and are naked and blind. After one week, fur covers the whole body, and after two weeks, the eyes are open and the fur coat is fully developed. Once the eyes are open, the young begin to emerge from the burrow and bask alone in the sun. They will eat grass while still nursing. The young initially do not exhibit a fear reaction to human approach when the the mother is absent, but after a few days, they quickly escape into the burrow when they sense humans. If they are caught, they emit high-pitched squeaks and attempt to bite the attacker with their weak teeth. At one month of age (often in middle-late June), they sometimes leave the burrow and investigate sown fields nearby.

Note: birth mass and juvenile time to independence is not known about this species.

Yearling males are scrotal and attempt to mate, but they are usually driven away from the females by older adult males, and often do not get the opportunity to mate in their first year. Female age of sexual maturity is not known. (Hayssen, 2008a; Hayssen, 2008c; Ognev, 1947; Thorington, et al., 2012; Titov, 2003)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  once a year

• Breeding season

  April to May

• Range number of offspring

  16 (high)

• Average number of offspring

  7 to 8

• Range gestation period

  23 to 31 days

• Average gestation period

  28.4 days

• Range weaning age

  29 to 60 days

• Average weaning age

  39.6 days

• Range age at sexual or reproductive maturity (male)

  1 (low) years

There is no mention in the literature regarding parental care from males. For the females, in addition to nursing, they will bring out their blind young on sunny days, in particular after a rain to bask in the sun. In one study, a burrow was excavated and blind young were found near the exit, where they were likely carried there by the mother because of the warmer soil. (Ognev, 1947)

• Parental Investment
• altricial
• female parental care
• pre-weaning/fledging
  • provisioning
    • female

Lifespan/Longevity

No information regarding the longevity of russet ground squirrels in captivity or in the wild is available. However, there is information regarding the longevity of other related Old World ground squirrels such as yellow ground squirrels (S. fulvus), which have a lifespan of approximately 5 to 6 years in the wild. In a different Old World ground squirrel species, European ground squirrels (S. citellus), the maximum lifespan observed was 4 years for the males and 6 years for the females. In general, it appears in the literature that the life expectancy of Old World ground squirrels is under 7 years. (Gorbunova, et al., 2008; Hoffmann, et al., 2003; Vasilieva and Tchabovsky, 2014)

Behavior

Russet ground squirrels are diurnal. The timing of their daily emergence from their burrows depends on the ambient temperatures and length of day. For example, in spring as it gets warmer and the days become longer, the squirrels emerge earlier and earlier from their burrows. In general, russet ground squirrels emerge between 0500 to 0600 hours, with the earliest emergence reported at 0400 hours, and the latest emergence at 0900 hours. They delay their emergence when it is cool and when it is very windy. These squirrels are active until midday (approximately 1000-1200 hours), when the temperatures become too warm for them, and they seclude themselves in their burrows where it is cooler. These squirrels reappear on the surface when it begins to cool at around 1800 hours, and will feed until around 2000 or until it is dark. If it is a cool and cloudy day, the squirrels may be observed on the surface between 1300 and 1600 hours. In addition, young squirrels will leave their burrows in the middle of the day, while the adults stay in their burrows. (Hayssen, 2008a; Helgen, et al., 2009; Ognev, 1947; Thorington, et al., 2012)

Russet ground squirrels undergo winter hibernation every year. Males enter hibernation in mid-June, while the females and juveniles begin hibernation in late August/early September. They awake from hibernation in April, with the males emerging before the females. Snow may still be present when the males awake. Females emerge once the snow has melted.

The active period ranges from 50 to 110 days each year in the Volga-Kama region (Russia). The duration of the active period is shorter than in smaller ground squirrel species. (Belovezhets and Nikol’skii, 2012; Kryštufek and Vohralík, 2012; Thorington, et al., 2012; Titov, 2004)

Russet ground squirrels are semi-fossorial, and create their own burrow, though they will occupied old burrows if the opportunity presents itself. Ground squirrels have four types of burrows: winter, permanent, temporary, and maternity.

Winter burrows are built in hard ground, and are used for hibernation. They are very deep and of simple construction. The vertical opening of the burrow is blocked with earth from within. In early spring, a layer of ice forms over the earth plug, this ice layers is assumed to function as a barrier against flooding from thaw waters.

Permanent burrows are also built in hard ground. They are constructed immediately following emergence from hibernation by some individuals. They are designed for solitary living (e.g. males). The depth of permanent burrows range from 40 to 150 cm. The total length of permanent burrows is typically between 1 to 1.5 m, but can reach 2 m in length. The main chamber is either situated in the middle of the burrow, or at the end. Two chamber burrows can also occur in this burrow type. Chambers usually occur at depths of 40 to 50 cm, but have been observed to occur at depths of 100 cm. Usually these burrows only have one exit.

Temporary burrows are shallower and simpler in construction than permanent burrows, where the temporary burrow depth ranges from 30 to 50 cm. These burrows are often used for escape from predators. They may have one or two exits with either vertical or slanting passages. Temporary burrows are usually found in sown fields, and often there will be several temporary burrows escavated near a permanent burrow.

Maternity burrows are constructed by pregnant females for the purpose of parturition and raising young. They are of more complex construction than other burrow types. They have longer passages and circuitous corridors, and frequently have two chambers and exits. Their nest chambers tends to be shallower than other burrow types, which allows for greater warmth of the nest chamber during spring and summer.

Generally, burrow entrance mounds are only found near sloping burrows, and never near vertical burrows. Burrows on hills are usually situated on southern slopes. The burrow temperatures are lower than ambient temperatures in both spring and summer, with a bigger temperature difference observed in spring than in summer. The width and height of the nest chambers ranges from 14 to 25 cm, and 12 to 18 cm respectively. The nest chambers are usually lined with dry grass, and are occasionally lined with dry horse manure. In addition, one or several extra passages may be observed in the burrows. The average passage width is 9.5 cm, with a range of 6 to 13 cm. Lastly, russet ground squirrels defecate inside their burrows. (Lagaria and Youlatos, 2006; Ognev, 1947; Thorington, et al., 2012)

Juvenile (young of the year) females tend to remain closer to the mother's nest burrow than the male juveniles. The new territories of the female juveniles often overlap with the mother's home range. Male juveniles are much more mobile than the females, and disperse farther from the maternity burrow to take advantage of areas of vacant space in the colony.

Both female and male juveniles tend to avoid activity centers of non-kin adults. During unfavorable population conditions for juvenile dispersal, such as close proximity to adults and high population densities, the juveniles prefer to settle closer to their kin (e.g. mother, sisters and brothers) instead of non-kin susliks.

Due to the high territoriality of neighboring adult ground squirrels, dispersing juveniles are actively prevented from entering their territories. The territorial adult ground squirrels do demonstrative dashes towards the juvenile intruders. However, the mothers are not aggressive towards their young, which allows the juveniles to gradually disperse, giving them a better chance at finding an unoccupied place in the colony. (Titov, 2003)

The time a russet ground squirrel spends in aggressive interactions depends on the season and sex. In general, males are more aggressive than females. Males are the most aggressive during the reproductive period (i.e. April), where 2.7% (C.I. 2.01% - 3.39%) of their time is spent on aggressive behavior. In comparison, females during their nursing period only spend 1.1% (C.I. 0.37% - 1.83%) of their time on aggressive behavior. During the fattening period (primarily May and June), aggression decreases for both sexes.

Often when two adult ground squirrels meet, such as when an intruder enters a territory, the master of the lot is always dominant, and the intruder will try to leave the territory without contact or conflict with the master. The intruder will usually display submissive behavior, and move away from the territory owner as part of a domination-subordination display. This domination-subordination behavior is a way to reduce aggression in contacts, and prevent injury.

Contacts between two territorial adult ground squirrels can result in three different outcomes. The first outcome is avoidance of interaction, where they sense each other and move away from each other (43.8% of contacts). The second outcome is domination-subordination behaviour, where the intruder displays submissive behavior and retreats (31.2 % of contacts). The third outcome is direct aggression which include biting, scratching, and chasing each other (25% of contacts). (Titov, et al., 2008)

Russet ground squirrels do not remain in the same burrow and territory over the summer. Males move first, and females move after completing lactation. Their excursions usually result in movements towards moist areas, such as near ravines and ponds. Towards the end of May, they begin to move together in cultivated fields. Large-scale shifts in location can occur for this species, often due to insufficient food resources in their burrow aras. Reports from local inhabitants have observed ground squirrels crossing the Ural (Russia) in large groups when the steppe grasses are dry in the summer. Other regions in Russia have also observed groups of migrating russet ground squirrels. Russet ground squirrels are able to swim starting at the age of 2 weeks, but tire quickly. (Ognev, 1947)

• Key Behaviors
• terricolous
• fossorial
• diurnal
• motile
• hibernation
• territorial
• social
• colonial

• Range territory size

  300 to 7500 m^2

Home Range

Russet ground squirrels are territorial. The territory size for male russet ground squirrels is approximately 0.75 ha (7500 sq. meters), and 0.03 ha (300 sq. meters) for the females. Female territories are within a male's territory. Russet ground squirrels mark their territory by peeing and cheek rubbing. Females are very territorial towards other females but there is an absence of interaction.

The densities of russet ground squirrels per hectare can vary. In the dry steppes of Saratov Zavolzh'ye (Russia), the highest colony densities were observed in river valleys (6.7 ± 0.5 to 11.2 ± 0.8 individuals per 1 ha depending on subregion), and the lowest in cereal crops (0.7 ± 0.05 to 2.4 ± 0.1 ind. per 1 ha), with forest edge habitats having moderate densities numbers (5.2 ± 0.3 to 7.9 ± 0.6 ind. per 1 ha). (Oparin and Oparina, 2009; Titov, 2004; Titov, et al., 2008)

Communication and Perception

Russet ground squirrels emit high pitched alarm calls when they perceive danger, as a warning to others in their colony. The alarm calls are species-specific for the Eurasian Spermophilus species, and therefore often used as a bioacoustic diagnostic when studying colonies where multiple ground squirrel species are present in close proximity. The alarm call duration of russet susliks is greater than 200 msec. Their alarm calls are longer in duration and have different frequency modulation than the red-cheeked ground squirrels (Spermophilus erythrogenys). The alarm calls of the red-cheeked and russet ground squirrels hybrids are a combination of the parents' alarm call signals; it is unique to the hybrids.

Communication between adult russet ground squirrels also involve a combination of chemical signals and visual cues. Russet ground squirrels engage in nasal and nasal sniffing, and nasal to anus sniffing in female-male mating interactions. They also use chemical signalling to mark territories. Russet ground squirrels depend on their eyesight to spot intruders and predators. They use their vision to observe the behavior and posture of their conspecifics in courtship rituals (e.g. the male observing if the female is displaying receptive behavior). They also use their vision to assess the behavior of intruders e.g. observing whether the intruder is in an aggressive or submissive stance. (Kryštufek and Vohralík, 2012; Nikolsky and Starikov, 1997; Spiridonova, et al., 2005; Thorington, et al., 2012; Titov, 2004; Titov, et al., 2008)

• Communication Channels
• visual
• acoustic
• chemical

• Other Communication Modes
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Russet ground squirrels are herbivores that forage on the ground and have cheek pouches that can temporarily store food. However, they do not store food in their burrows. They eat leaves and seeds of grasses and forbs, some roots and bulbs, flowers (e.g. Adonis volgensis), and cereal grains such as wheat, rye, oats, and millet. They prefer to eat the starchiest parts of the plants such as wheat ears, tops of shoots and leaves of various grasses, and bulbs. Russet ground squirrels can eat up to 228 g of the same vegetable type in a single day, and an average of 123.7 g (range: 84 to 194 g) of varied foods in a day. In contrast, they can only eat an average of 49.9 g (range: 14.9 to 71.6 g) of cereal crops per day.

Crop plants that russet ground squirrels consume include wheat, rye, sunflowers, pumpkins, potatoes, millet, and oats. Wild plants they eat include green foxtail (Setaria viridis), yarrow (Achillea millefolium and A. nobilis), lesser bindweed (Convolvulus arvensis), goosefoot (Chenopodium albus), white sweet clover (Melilotus albus), yellow sweet clover (M. officinalis), blue bur lappula (Echinospermum spp.), mallow (Malva rotundifolia), Austrian wormwood (Artemisia austriaca), koeleria (Koeleria gracilis), couch grass (Agropyrum sibiricum), common saltwort (Salsola kali), starwort (Aster villosus), sheep fescue (Festuca ovina), and feather grass (Stipa spp.).

Russet ground squirrels also opportunistically eat ground nesting bird eggs and nestlings. They eat wheatear nestlings (Saxicola oenanthe), tawny pipits eggs and young (Anthus campestris), and eggs of various skylarks. In addition, they occasionally eat small murine rodents and small amounts of insects. In addition, russet susliks in captivity will eat lizards (Lacerta agilis) and young sparrows.

In situations of no food or water availability, males of average plumpness will remain alive and alert for 15 days, while females of average plumpness can only remain alert for 5 days. In the case of very fat males (e.g. 1,342 g), they can survive up to 39 days. (Hayssen, 2008a; Kryštufek and Vohralík, 2012; Ognev, 1947; Thorington, et al., 2012)

• Primary Diet
• herbivore
  • folivore
  • granivore

• Animal Foods
• birds
• mammals
• eggs
• insects

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts
• flowers

Predation

Information regarding predators and anti-predator behaviors for russet ground squirrels is limited. Raptors seem to be their primary predator, such as the eastern imperial eagles (Aquila heliaca). They are also hunted and trapped by humans for their pelts and as a pest control measure.

Russet ground squirrels emit relatively short and high pitched alarm calls when they sense a predator, and will take cover in the nearest burrow. The burrow may not even belong to them. Russet ground squirrels take cover in marmot burrows, even if they are still inhabited by the marmots. (Bekmansurov, et al., 2015; Ognev, 1947; Thorington, et al., 2012)

• Known Predators

  • eastern imperial eagles (Aquila heliaca)

Ecosystem Roles

The ecological role of russet ground squirrels has not been directly studied, but has been in other ground squirrels, such as the California ground squirrel (Spermophilus beecheyi). The following information on russet ground squirrels role in ecosystems are speculations based on available information on the species in the genus Spermophilus.

The construction of burrows helps with soil aeration and creates habitat for other animals. Russet ground squirrels also change the soil chemical structure by their digging activity, and can change species compositions in pastures by preferentially consuming certain plants or parts of plants.

Russet ground squirrels function both as predators and prey in the steppe ecosystem. They prey upon eggs and nestlings of ground nesting birds, and occasionally eat small murine rodents and insects. In turn, they are prey to raptors.

Very few parasites species are known. Russet ground squirrels carry lice such as Neohaematopinus laeviusculus, and likely carry flea and tick species similar to Spermophilus pygmaeus, one of the ground squirrel species russet ground squirrels hybridize with. Spermophilus pygmaeus has flea species of Ceratophyllus tesquorum, Neopsilla setosa, Ctenophthalmus breviatus, and Frontopsilla semura, and tick species of Ixodes laguri and Rhipicephalus schulzei. Russet ground squirrels can be a vector of the bubonic plague, so it is possible it shares similar flea species and potentially tick species with S. pygmaeus. (Aronovich, 2008; Belovezhets and Nikol’skii, 2012; Ognev, 1947; Thorington, et al., 2012; Yensen, et al., 1996)

• Ecosystem Impact
• creates habitat
• soil aeration

Economic Importance for Humans: Positive

Humans capture russet ground squirrels for their pelts, but overall the pelts play a minor part in the fur trade. (Aronovich, 2008; Ognev, 1947)

• Positive Impacts
• body parts are source of valuable material

Economic Importance for Humans: Negative

Russet ground squirrels are both crop pests and carriers of disease. They are carriers of the bubonic plague like several other sympatric Old World ground squirrels e.g. yellow ground squirrels and little ground squirrels. Russet ground squirrels can also carry rabbit-fever infection.

Russet ground squirrels are considered serious crop pests of wheat, rye and millet. It has been suggested that 30 russet ground squirrels can destroy an entire hectare of wheat in approximately 40 days. An adult russet ground squirrel, during the active period, can consume up to 15 kg of fresh vegetable mass, which is equivalent to about 8 kg of hay. It has been estimated through experiments, that if they were to feed exclusively on cereals, that one adult squirrel would consume 8.5 kg throughout the active period.

Russet ground squirrels can significantly thin out sowed crops, and in some cases completely destroying them by digging out the sown seeds and eating the shoots. These ground squirrels also damage sugar-beet crops and protective forest shelter belts, in particular oaks, by digging out their acorns. In pastures, the ground squirrels eat the most valuable fodder crops, resulting in an undesirable change in the species structure of the pasture. In addition, the active digging activity of russet ground squirrels changes the soil chemical structure. (Aronovich, 2008; Ognev, 1947)

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Conservation Status

Russet ground squirrels are a widespread and abundant species, and are considered Least Concern by the IUCN Red List. Some populations are declining in some regions, but the overall population growth patterns are currently unknown. (Tsytsulina, et al., 2008)

• IUCN Red List

  Least Concern

Other Comments

Russet ground squirrels go by several common names, such as the hibernating large ground squirrel, large-toothed suslik, and reddish ground squirrel. Note that the word 'suslik' is interchangeable with the term 'ground squirrel' for this species, and that suslik can also be spelled as souslik.

In addition, Spermophilus major has been known by other scientific names in the past:

• 1778/1779: Mus citellus var. major (Pallas)
• 1840: Spermophilus rufescens (Keyserling & Blasius)
• 1840: Arctomys undulatus (Eversmann)
• 1850: Arctomys rufescens (Eversmann)
• 1852: Spermophilus rufescens (Brandt)
• 1915: Citellus rufescens (Martino)
• 1947: Citellus major (Bažanov)
• 1952: Citellus major argiropuloi (Vinogradov et Gromov)
(Aronovich, 2008; Bekmansurov, et al., 2015; Belovezhets and Nikol’skii, 2012; Kryštufek and Vohralík, 2012; Ognev, 1947; Titov, et al., 2012)

Contributors

Ellyne Geurts (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Aronovich, K. 2008. Citellus (Colobotis) major. A Afonin, S Greene, N Dzyubenko, A Frolov, eds. Interactive agricultural ecological atlas of Russia and neighboring countries. Economic plants and their diseases, pests and weeds. St. Petersburg, Russia: All Russian Institute of Plant Protection [online]. Accessed August 20, 2017 at http://www.agroatlas.ru/en/content/pests/Citellus_major/.

Aronovich, K., A. Afonin ed., S. Greene ed., N. Dzyubenko ed., A. Frolov ed.. 2008. "Citellus (Colobotis) major" (On-line). Interactive agricultural ecological atlas of Russia and neighboring countries. Economic plants and their diseases, pests and weeds. Accessed August 20, 2017 at http://www.agroatlas.ru/en/content/pests/Citellus_major/.

Bekmansurov, R., I. Karyakin, E. Shnayder. 2015. On eastern imperial eagle (Aquila heliaca) breeding in atypical habitat under competitive conditions with other eagle species. Slovak Raptor Journal, 9: 95-104.

Belovezhets, K., A. Nikol’skii. 2012. Temperature regime in burrows of ground squirrels (Marmotinae) during winter hibernation. Russian Journal of Ecology, 43/2: 155-161.

Ermakov, O., S. Titov. 2000. Dynamics of Spermophilus major (Rodentia, Sciuridae) range boundaries in the Volga river region. Zoologicheskiiì Zhurnal, 79/4: 503-509.

Gorbunova, V., M. Bozzella, A. Seluanov. 2008. Rodents for comparative aging studies: from mice to beavers. AGE, 30: 111-119.

Hayssen, V. 2008. Patterns of body and tail length and body mass in Sciuridae. Journal of Mammalogy, 89/4: 852-873.

Hayssen, V. 2008. Reproduction within marmotine ground squirrels (Sciuridae, Xerinae, Marmotini): patterns among genera. Journal of Mammalogy, 89/3: 607-616.

Hayssen, V. 2008. Reproductive effort in squirrels: ecological, phylogenetic, allometric, and latitudinal patterns. Journal of Mammalogy, 89/3: 582-606.

Helgen, K., F. Cole, L. Helgen, D. Wilson. 2009. Generic revision in the Holarctic ground squirrel genus Spermophilus. Journal of Mammalogy, 90/2: 270-305.

Hoffmann, I., E. Millesi, S. Huber, L. Everts, J. Dittami. 2003. Population dynamics of European ground squirrels (Spermophilus citellus) in a suburban area. Journal of Mammalogy, 84/2: 615-626.

Kryštufek, B., V. Vohralík. 2012. Taxonomic revision of the Palaearctic rodents (Rodentia): Sciuridae: Xerinae 1 (Eutamias and Spermophilus). Lynx, series nova, 43: 17-111.

Lagaria, A., D. Youlatos. 2006. Anatomical correlates to scratch digging in the forelimb of European ground squirrels (Spermophilus citellus). Journal of Mammalogy, 87/3: 563-570.

Matějů, J., L. Kratochvíl. 2013. Sexual size dimorphism in ground squirrels (Rodentia: Sciuridae: Marmotini) does not correlate with body size and sociality. Frontiers in Zoology, 10/27: 1-10. Accessed September 30, 2016 at http://www.frontiersinzoology.com/content/10/1/27.

Nikolsky, A., V. Starikov. 1997. Variability of alarm calls in Spermophilus major and Spermophilus erythrogenys (Rodentia, Sciuridae) within contact zone in Kugan district. Zoologicheskiiì Zhurnal, 76/7: 845-857.

Ognev, S. 1947. Mammals of U.S.S.R. and adjacent countries. Vol V Rodents. Moscow: (English translations 1963, Israel Program for Scientific Translations).

Okulova, N., L. Khlyap, F. Bidashko, A. Warshavskyi, A. Grazhdanov, V. Neronov. 2014. Rodent communities in western Kazakhstan Oblast of the Kazakhstan Republic. II. zoogeography characteristics. Arid Ecosystems, 4/3: 187-193.

Oparin, M., O. Oparina. 2009. The role of anthropogenic and natural factors in changes in mesophilic rodent distribution in steppes between the Ural and Volga rivers. Biology Bulletin, 36/4: 380-387.

Rumyantsev, V., O. Ermakov, V. Il'in, A. Dobrolyubov, M. Soldatov, E. Danilenko. 2012. On the history and modern state of the steppe marmot (Marmota bobak Müll in Penza Oblast. Arid Ecosystems, 2/2: 111-119.

Shmyrov, A., A. Kuz’min, A. Kuz’min, S. Titov. 2011. Breeding Success and direction of animal crossing in the hybrid russet (Spermophilus major) and yellow (Spermophilus fulvus) ground squirrel population. Biology Bulletin, 38/5: 440-445.

Shmyrov, A., A. kuzmin, A. Kuzmin, S. Titov. 2012. Characterization of hybrids between the russet (Spermophilus major) and the yellow (Spermophilus fulvus) ground squirrels according to morphological and acoustic attributes. Zoologicheskiiì Zhurnal, 91/1: 119-126.

Spiridonova, L., G. Chelomina, V. Starikov, V. Korablev, M. Zvirka, E. Lyapunova. 2005. RAPD–PCR analysis of ground squirrels from the Tobol–Ishim Interfluve: evidence for interspecific hybridization between ground squirrel species Spermophilus major and S. erythrogenys. Russian Journal of Genetics, 41/9: 991-1001.

Spiridonova, L., G. Chelomina, K. Tsuda, H. Yonekawa, V. Starikov. 2006. Genetic evidence of extensive introgression of short-tailed ground squirrel genes in a hybridization zone of Spermophilus major and S. erythrogenys, inferred from sequencing of the mtDNA cytochrome b gene. Russian Journal of Genetics, 42/7: 802-809.

Thorington, J., J. Koprowski, M. Steele, J. Whatton. 2012. Squirrels of the world. Baltimore, US: John Hopkins University Press.

Titov, S. 2000. Habitat preference in Spermophilus major and S. suslicus in recently developed sympatric zone. Zoologicheskiiì Zhurnal, 79/1: 64-72.

Titov, S. 2003. Juvenile dispersal in the colonies of Spermophilus major and S. suslicus ground squirrels. Russian Journal of Ecology, 34/4: 255-260.

Titov, S. 2004. Reproductive behaviour of the russet souslik, Spermophilus major (Rodentia, Sciuridea). Zoologicheskiiì Zhurnal, 83/9: 1148-1159.

Titov, S., A. Shmyrov, A. Kuzmin, O. Ermakov. 2008. Agonistic behavior of the russet ground squirrel (Spermophilus major, Rodentia, Sciuridae). Zoologicheskiiì Zhurnal, 87/9: 1124-1133.

Titov, S., A. Shmyrov, A. Kuz’min. 2012. Biotope principles of sympatry and interspecies hybridization in mammals (by the example of the genus Spermophilus). Biology Bulletin, 39/1: 36-44.

Tsytsulina, K., N. Formozov, B. Sheftel. 2008. "Spermophilus major (Russet ground squirrel)" (On-line). IUCN Red List of Threatened Species. Accessed September 30, 2016 at http://www.iucnredlist.org/details/20486/0.

Vasilieva, N., A. Tchabovsky. 2014. Timing is the only thing: reproduction in female yellow ground squirrels (Spermophilus fulvus). Canadian Journal of Zoology, 92: 737-747.

Yensen, E., C. Baird, P. Sherman. 1996. Larger ectoparasites of the Idaho ground squirrel (Spermophilus brunneus). Great Basin Naturalist, 56/3: 237-246.