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Spermophilus fulvusyellow ground squirrel

By Rebekah Shorter

Geographic Range

Yellow ground squirrels (Spermophilus fulvus) can be found as far north as Russia and Kazakhstan, ranging as far west as the Caspian Sea and the Volga River and as far east as Lake Balkash. The contiguous southern range spreads down through Uzbekistan, western Tajikistan and Turkmenistan. There are additional disjunct populations of yellow ground squirrels that are found in northeastern Iran, Afghanistan, and Kashi, China. (Tsytsulina, et al., 2008)

Habitat

Yellow ground squirrels live in a terrestrial biome. The habitat of yellow ground squirrels consists of sand, clay, and loess deserts and semi-deserts. The ground squirrels also live in forest zones with alkali and saltwort alkali soils. The maximum elevation of the habitat of these squirrels is 1000 meters. Yellow ground squirrels use natural and artificial elevated areas to construct their burrows. Titov et al., (2012) found that man-made disturbed steppe and semi-dessert areas, such as dumping sites and non-structured cattle pastures in settlements, are where many burrows of yellow ground squirrels are found. Other sources suggest that the squirrels do not come into contact with humans or agricultural areas often. (Titov, et al., 2012; Tsytsulina, et al., 2008; Vasilieva and Tchabovsky, 2014)

  • Range elevation
    1000 (high) m
    3280.84 (high) ft

Physical Description

As their name suggests, yellow ground squirrels have a yellowish upper body with black tipped hairs that create a finely speckled look. With an adult body mass ranging from 307 to 1428 grams and a body length (not including the tail) ranging from 230 to 370 millimeters, the yellow ground squirrel is the largest-sized genus Spermophilus ground squirrel. The juvenile body mass of the yellow ground squirrel ranges from 173 to 555 grams. Volodina et al., 2010 reports that the overall average body mass of juvenile yellow ground squirrels to be 283 grams and the overall average body mass of adults to be 819 grams. Matrosova et al., 2011 found that the male juvenile average body mass is 309 grams, the male adult average body mass is 1343 grams, the female juvenile average body mass is 275 grams, and the female adult average body mass is 856 grams. The average body mass for male yellow ground squirrels is larger than the average body mass for female yellow ground squirrels. (Matrosova, et al., 2010; Matrosova, et al., 2011; Volodina, et al., 2010)

  • Sexual Dimorphism
  • male larger
  • Range mass
    307 to 1428 g
    10.82 to 50.33 oz
  • Average mass
    819 g
    28.86 oz
  • Range length
    230 to 370 mm
    9.06 to 14.57 in

Reproduction

Yellow ground squirrels are seasonal breeders, usually breeding during March and April. The male yellow ground squirrels emerge from hibernation 1-2 weeks before the females. Beyond this, nothing else is known about the mating habits of this species. (Vasilieva and Tchabovsky, 2014)

Yellow ground squirrels are iteroparous and reproduce sexually. Female yellow ground squirrels can produce one litter per year and have an average of 5 pups per breeding season but can range from 1 pup to 10 pups. The average gestation period is 30 days. The breeding season usually starts in March and early April, right after they emerge from hibernation in mid-February. Male yellow ground squirrels emerge from hibernation first, and about 1-2 weeks later the females will emerge. Female ground squirrels have about 3 months to mate and gain body weight before entering hibernation in late June. Juvenile ground squirrels emerge usually in April-May, giving them about 2 months to gain weight before their first hibernation. The average offspring mass at birth is 191 grams with a range of 104 to 290 grams. The squirrels will reach their adult size by the summer after their first hibernation. The female yellow ground squirrels are capable of reproducing after their first hibernation while the males are not able to reproduce until after their second hibernation. The average age at reproductive maturity for the females is one year old and the average age at reproductive maturity for the males is two years old. (Hayssen, 2008; Kashkarov and Lein, 1927; Matrosova, et al., 2007; Matrosova, et al., 2008; Vasilieva and Tchabovsky, 2014)

  • Breeding interval
    Yellow ground squirrels breed once yearly
  • Breeding season
    March through April
  • Range number of offspring
    1 to 10
  • Average number of offspring
    5
  • Average gestation period
    30 days
  • Average weaning age
    30 days
  • Range time to independence
    1 to 2.5 months
  • Average time to independence
    2 months
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    2 years

Yellow ground squirrel pups are born in burrows which allows for protection from predators. The ground squirrel pups are born undeveloped and require care and feeding from their mothers. The female squirrels protect and care for the young, having extended social contact with their young up until their first hibernation. The mothers teach the pups how to make alarm calls. It is not apparent that the males are involved except during the mating process. (Hayssen, 2008; Matrosova, et al., 2008; )

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

Lifespan/Longevity

Yellow ground squirrels live between five to six years in the wild. Once the female ground squirrels reach sexual maturity, around one year of age, the mortality rate increases. Seventy percent of female ground squirrels die before their third hibernation and eighty-seven percent die before their fourth hibernation. The longest captive lifespan for members of the genus Spermophilus is 11 years. (Carey and Judge, 2000; Vasilieva and Tchabovsky, 2014)

  • Typical lifespan
    Status: wild
    5 to 6 years

Behavior

Yellow ground squirrels live in burrows underground and are active during the day. The squirrels typically have low population densities of about 3 to 10 individuals per hectare. The female ground squirrels tend to stay close to their natal burrows whereas the males move farther away.

Yellow ground squirrels usually emerge from hibernation in mid-February when the vegetation starts to green up. In the middle of March the ground squirrels begin mating and during this time, they do not eat very much. After mating, the squirrels will spend all day eating and they gain weight quickly. When the sun rises, the ground squirrels exit their burrows and begin to eat the vegetation nearby. Around the middle of the day, as it warms, the squirrels will return to their burrows. Later in the afternoon, the ground squirrels will come back out of the burrow for a short period. In 24 hours, the ground squirrels will have consumed, on average, 275 grams of vegetation. The squirrels continue to eat until the availability of suitable forage declines, usually early June, and then they enter hibernation. (Kashkarov and Lein, 1927)

Home Range

The home range of yellow ground squirrels is unknown. (Kashkarov and Lein, 1927)

Communication and Perception

Yellow ground squirrels have an advanced sociality compared to the smaller species in the genus Spermophilus. They have burrows in close proximity to each other which allows them to hear the alarm calls of neighbors and respond to them. The alarm call is the most common and the loudest call used by yellow ground squirrels. The structure of the alarm calls of the ground squirrels is the same in all predatory situations, such as humans, some harmless animals, terrestrial predators, and raptors. Juvenile ground squirrels have an alarm call that is very close to the alarm call of the adult squirrels. The pitch of the alarm call is lower in the juveniles than in the adults, which is not common among mammals. (Matrosova, et al., 2010)

Food Habits

Yellow ground squirrels are herbivores. The ground squirrels that inhabit the desert and semi-desert areas feed on desert vegetation which is their only source of metabolic water. The main sources of vegetation that yellow ground squirrels consume is bulbous bluegrass (Poa bulbosa), Carex grasses (Carex hostii), and a flowering plant (Malcolmia turkestanica). Yellow ground squirrels are active as long as the period of vegetation lasts. During the mating season the ground squirrels don't spend much time eating. After the mating season the squirrels spend most of the day eating to gain weight before hibernation. (Kashkarov and Lein, 1927)

  • Plant Foods
  • leaves

Predation

Yellow ground squirrels are one of the main prey of eastern golden eagles (Aquila chrysaetos), imperial eagles (Aquila heliaca), and steppe eagles (Aquila nipalensis). These squirrels warn others of predators through an alarm call. Steppe polecats (Mustela eversmanii) and marbled polecats (Vormela peregusna) hunt in burrows and prey upon young ground squirrels. These polecats do not eat adults. Matrosova et al. (2007) state that there are cases of infanticide where neighbors, both male and female ground squirrels, will kill the young. They further suggest that because some predators that only attack juvenile squirrels, the young may mimic the adults alarm calls as a way to discourage such juvenile-specific predators. (Karyakin, et al., 2011; Matrosova, et al., 2007; Matrosova, et al., 2008)

Ecosystem Roles

Yellow ground squirrels eat desert grasses. The squirrels provide a food source for the predators that hunt them, such as eagles and polecats. Common parasites of yellow ground squirrels are northern rat fleas (Nosopsyllus fasciatus), sucking lice (Enderleinellus propinquus and Linognathoides laeviusculus), ticks (Hyalomma asiaticum), and protists (Eimeria airculensis, Eimeria berkinbaevi, Eimeria deserticola, and Eimeria susliki). (Apanaskevich and Horak, 2010; Durden and Musser, 1994; Hamidi, et al., 2016; Karyakin, et al., 2011; Kashkarov and Lein, 1927; Wilber, et al., 1998)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Yellow ground squirrels are hunted by humans. The squirrels are often hunted commercially and sold for profit. There was not much information found on the price, uses, or locations of the hunting. (Tsytsulina, et al., 2008)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no adverse economic effects of yellow ground squirrels on humans. (Kashkarov and Lein, 1927)

Conservation Status

There is no special status listed for yellow ground squirrels for the CITES appendices or the United States Endangered Species Act list, but it is listed as "Least Concern" on the IUCN Red List. Commercial hunting is a potential threat and has affected some populations in areas of Russia and Kazakhstan but has not caused a substantial decline in the population. There are no conservation acts to protect the yellow ground squirrels. (Tsytsulina, et al., 2008)

Contributors

Rebekah Shorter (author), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Jacob Vaught (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Palearctic

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

World Map

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

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

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

herbivore

An animal that eats mainly plants or parts of plants.

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.

seasonal breeding

breeding is confined to a particular season

sexual

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

tactile

uses touch to communicate

terrestrial

Living on the ground.

viviparous

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

References

Apanaskevich, D., I. Horak. 2010. The genus Hyalomma. XI. Redescription of all parasitic stages of H. (Euhyalomma) asiaticum (Acari: Ixodidae) and notes on its biology. Experimental & Applied Acarology, 52/2010: 207-220.

Carey, J., D. Judge. 2000. Longevity Records: Life Spans of Mammals, Birds, Amphibians, Reptiles, and Fish. Denmark: Odense University Press.

Durden, L., G. Musser. 1994. The mammalian hosts of the sucking lice (Anoplura) of the world: A host-parasite list. Bulletin of the Society of Vector Ecology, 19/2: 130-168.

Hamidi, K., L. Nourani, G. Moravvej. 2016. New rodents' hosts of sucking lice, fleas (Insecta: Anoplura, Siphonaptera) and hard ticks (Acari: Ixodida) from Iran. Persian Journal of Acarology, 5/1: 85-88.

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

Karyakin, I., A. Kovalenko, A. Levin, A. Pazhenkov. 2011. Eagles of the Aral-Caspian Region, Kazakhstan. Raptors Conservation, 22/2011: 92-152.

Kashkarov, D., L. Lein. 1927. The yellow ground squirrel of Turkestan, Cynomys fulvus oxianus Thomas. Ecology, 8/1: 63-72.

Matrosova, V., D. Blumstein, I. Volodin, E. Volodina. 2011. The potential to encode sex, age, and individual identity in the alarm calls of three species of Marmotinae. Die Naturwissenschaften, 98/3: 181-192.

Matrosova, V., I. Volodin, E. Volodina. 2008. Does kinship affect the alarm call structure in the yellow ground squirrel (Spermophilus fulvus)?. Lynx, series nova, 39/2: 295-304.

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

Matrosova, V., I. Volodin, E. Volodina, N. Vasilieva, A. Kochetkova. 2010. Between-year stability of individual alarm calls in the yellow ground squirrel Spermophilus fulvus. Journal of Mammalogy, 91/3: 620-627.

Neronov, V., S. Shilova. 2012. The state of vegetation during drought and its influence on the hibernation period of yellow ground squirrels (Spermophilus fulvus Licht. 1823) in the Saratov Trans-Volga region. Biology Bulletin, 39/10: 805-808.

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.

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 fulvus" (On-line). The IUCN Red List of Threatened Species 2008: e.T20484A9206499. Accessed January 28, 2016 at http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T20484A9206499.en.

Vasilieva, N., A. Tchabovsky. 2014. Timing is the only thing: Reproduction in female yellow ground squirrels (Spermophilus fulvus). Canadian Journal of Zoology, 92/8: 737-747.

Vasilieva, N., A. Tchabovsky. 2015. A shortage of males causes female reproductive failure in yellow ground squirrels. Science Advances, 1/9: e1500401.

Vasilieva, N., E. Pavlova, S. Naidenko, A. Tchabovsky. 2014. Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season. Current Zoology, 60/6: 700-711.

Volodina, E., V. Matrosova, I. Volodin. 2010. An unusual effect of maturation on the alarm call fundamental frequency in two species of ground squirrels. Bioacoustics, 20/1: 87-98.

Wilber, P., D. Duszynski, S. Upton, R. Seville, J. Corliss. 1998. A revision of the taxonomy and nomenclature of the Eimeria spp. (Apicomplexa: Eimeriidae) from rodents in the tribe Marmotini (Sciuridae). Systematic Parasitology, 39/1998: 113-135.

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