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Spermophilus suslicusspeckled ground squirrel

By Ryan Nutter

Geographic Range

The geographic range of speckled ground squirrels (Spermophillus suslicus) occurs in the Palearctic range, specifically eastern Europe. Their range extends east from a small portion in south-eastern Poland towards the Volga River in central Russia. The distribution of speckled ground squirrels occurs in most parts of Ukraine and Moldova. Small fragmented populations are present in east and western parts of Belarus. (Gondek, et al., 2006; Zagorodnyuk, et al., 2008)

Habitat

Speckled ground squirrels can occupy an array of habitats throughout the Palearctic range. Their typical habitat is the steppe areas or steppe meadows that occur throughout their north central distribution. They also tend to prefer cultivation sites, pasturelands, and open areas with low lying vegetation. (Gondek, 2007; Shilova, et al., 2010; Zagorodnyuk, et al., 2008)

  • Range elevation
    0 to 500 m
    0.00 to 1640.42 ft

Physical Description

Speckled ground squirrels are a small ground dwelling diurnal rodents, with an elongated body and short tail. They can reach lengths of 190 to 220 mm, and weigh from 180 to 220 g. The unique characteristic they can be identified by is the white tipped hairs that ultimately make up a speckled arrangement on the dorsal side of the body. They are predominately dark brown with a light cream color on their undersides, and they have short powerful legs. Speckled ground squirrels occur in the squirrel family, and have three subspecies: Spermophilus suslicus guttatus, S. s. boristhenicus, and S. s. suslicus. Speckled ground squirrels are easily identifiable and distinguished by their prominent white specks across its back. Juveniles or pups do not leave the den until maturity is reached, making it difficult to distinguish by color. European ground squirrels are closely related and may cause some identification issues due to similarities in appearance. European ground squirrels can be identified from their light brown coloration and white region from its jugular down the ventral side. (Gondek, 2007; Matrosova, et al., 2009; Volodin, et al., 2008)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    180 to 220 g
    6.34 to 7.75 oz
  • Range length
    190 to 220 mm
    7.48 to 8.66 in

Reproduction

During the mating season just after females have emerged from hibernation, males use individuality in calls to attract females, and deter other males. They only breeds once a year right after hibernation. The males will mate with multiple females, and the females will raise the pups in a colony. Many of these colonies are experiencing population bottlenecks, raising the probability of inbreeding. (Biedrzycka and Radwan, 2008; Matrosova, et al., 2009)

Speckled ground squirrels breed once yearly. Their breeding season occurs for two weeks as the females emerge from hibernation. Due to climatic conditions, they tend to have low intensity of breeding and low fertility rates. During late April and early May pups are born; these pups typically spend one month in the burrow until they disperse from the den. Information for gestation period and litter size is insufficient, however they can be compared to close relatives European ground squirrels. The gestation period of European ground squirrels lasts 27 days and the litter size on average is 6 pups. (Gondek, 2007; Matrosova, et al., 2009; Shilova, et al., 2010; Yu, 1995)

  • Breeding interval
    Speckled ground squirrels breed once yearly.
  • Breeding season
    Speckled ground squirrels breed in March to April after they emerge from hibernation.
  • Average number of offspring
    6
  • Average gestation period
    27 days
  • Average weaning age
    30 days
  • Range time to independence
    3 to 5 weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Speckled ground squirrels give birth to a litter in early spring, with an average of 6 pups per litter. These pups are born underground, giving them protection from the elements and predators. Females tend to care for and protect the litters. Over the course of the weaning period, juveniles adapt to and learn alarm calls. It is noted that selective calling to juveniles and call rate is directly correlated to the emergence of young pups out of the den, suggesting there is some parental care. They spend much of their time viewing their surroundings and sounding alarm calls when predators are near, alarming the colony to take shelter. (Matrosova, et al., 2009; Yu, 1995)

  • Parental Investment
  • altricial
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

Speckled ground squirrels on the high end can reach an age of six years. Juveniles are more vulnerable and less likely to make it through the first year. As juveniles, they contribute to 73% of the mortality rate, while adults only contribute to 58% of the mortality rates. There are no records of the speckled ground squirrels in captivity. (Matrosova, et al., 2009; Shilova, et al., 2010)

  • Range lifespan
    Status: wild
    6 (high) years

Behavior

Speckled ground squirrels are ground dwelling fossorial mammals. They spend a majority of their time on their hind legs scanning the surroundings in search of predators. Communication plays a vital role in survival for these squirrels; they tend to occupy sites of vast open grasslands making them vulnerable to visual predation. They not only use vocalizations for alarm calls, but also mating calls to fend off rival males and attract females. They dig burrows vertically and horizontally, the vertical burrows are temporary structures, whereas horizontal burrows are used for birthing and weaning pups. (Gondek, 2007; Matrosova, et al., 2009)

  • Range territory size
    0.02 to 0.28 km^2

Home Range

Speckled ground squirrels live in large colonies, ranging from a couple individuals to 300 individuals per hectare. Most colonies are compact, having a home range of 2 to 28 hectares. They occupy vast areas that contain many burrows throughout. Many colonies can be located within 5 to 14 kilometers of each other. (Shilova, et al., 2010; Volodin, et al., 2008)

Communication and Perception

Communication through vocalization plays a key role in the daily survival of speckled ground squirrels. They specialize in alarm calls that aid in alerting the colony of any potential predators. The speckled ground squirrel spends a vast majority of its time searching for predators, so they have developed visual acuity over time. Their alarm calls may be specialized to individuals in some cases. One good examples occurs when females develop individualized alarm calls when juvenile dispersal occurs. (Gondek, 2007; Matrosova, et al., 2009; Volodin, et al., 2008)

Food Habits

Speckled ground squirrels are most commonly be found eating sprouts. In some cases they eat grains, insects, and grasses. Some speckled grounds squirrel diets consist of bunch grasses (Festuca rubra) and motley grasses (Fragaria viridis, Eryngium planum, Pimpinella saxigraga). (Gondek, 2007; Shilova, et al., 2010)

  • Animal Foods
  • insects
  • Plant Foods
  • roots and tubers
  • seeds, grains, and nuts
  • flowers

Predation

Speckled ground squirrels have evolved certain anti-predator adaptions over time. Their main anti-predator adaption is the acoustic communication between individuals in the colony allowing them to alert the colony of predators within close proximity. Speckled ground squirrels are fossorial, allowing for them to easily escape predation by going underground. They have very good eyesight, relentlessly observing the surroundings for potential predators. (Gondek, 2007; Matrosova, et al., 2007)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Speckled ground squirrels have some influence on soil aeration and altering habitat. They are fossorial; each individual in the colony digs multiple burrows throughout a landscape, which ultimately enhances soil aeration. Though they are only digging burrows they are also creating possible shelter for other species. (Gondek, 2007; Shilova, et al., 2010)

Economic Importance for Humans: Positive

Speckled ground squirrels have been studied on multiple levels from individuality in alarm calls to the dynamics of colonies of speckle ground squirrels. Studying these squirrels has allowed groups to learn more about conservation and population management. (Gondek, 2007; Volodin, et al., 2008)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

There are no known adverse effects of the speckled ground squirrel (Spermophilus suslicus) on humans.

Conservation Status

Currently speckled ground squirrels are near threatened, and completely protected in Poland under national law. They are also listed as endangered in the Polish Red Data Book and considered a Priority Species in the European Union Habitats Directive. There have been five newly constructed nature reserves in Poland to aid population conservation efforts. It has been proposed to use translocation for individuals from large colonies to boost genetic variation in other colonies at risk of deleterious genetic effects of bottlenecks. Agriculture has diminished much of their native habitat, and efforts to rebuild have been pursued. (Biedrzycka and Radwan, 2008; Gondek, 2007; Zagorodnyuk, et al., 2008)

Contributors

Ryan Nutter (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Laura Podzikowski (editor), Special Projects.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Biedrzycka, A., J. Radwan. 2008. Population fragmentation and major histocompatability complex variation in spotted suslik, Spermophilus suslicus. Molecular Ecology, 17: 4801-4811.

Gondek, A. 2007. Saving the Suslik. Focus on Nature Conservation, 2/14: 18-21.

Gondek, A., M. Verduijn, K. Wolff. 2006. Polymorphic microsatellite markers for endangered spotted suslik, Spermophilus suslicus. Molecular Ecology Notes, 6: 359-361.

Matrosova, V., I. Volodin, E. Volodina. 2009. Short-Term and Long-Term Individuality in Speckeled Ground Squirrel Alarm Calls. Journal of Mammalogy, 90/1: 158-166.

Matrosova, V., I. Volodin, E. Volodina, A. Babitsky. 2007. Pups crying bass: vocal adaptation for avoidance of age-dependent predation risk in ground squirrels?. Behavior Ecology and Sociobiology, 62/2: 181-191.

Shilova, S., V. Neronov, O. Shekarova, L. Savinetskaya. 2010. Dynamics of Colonies of the Speckled Ground Squirrel (Spermophilus suslcus Guld., 1770) on the Northern Boundary of the Habitat. Biology Bulletin, 37/5: 532-536.

Volodin, I., E. Volodina, V. Matrosova, L. Savinetskaya, O. Shekarova, V. Voytsik. 2008. Population density does not affect the alarm call characteristics in speckled ground squirrel (Spermophilus suslicus). Lynx, 39/2: 333-342.

Yu, H. 1995. "Spermophilus citellus-European ground squirrel" (On-line). Animal Diversity Web. Accessed August 22, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Spermophilus_citellus.html.

Zagorodnyuk, I., Z. Glowacinski, A. Gondek. 2008. "Spermophilus suslicus (Speckled Ground Squirrel, SPECKLED GROUND SQUIRREL, Spotted Souslik)" (On-line). The IUCN Red List of Threatened Species. Accessed August 21, 2012 at http://www.iucnredlist.org/details/20492/0.

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