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Spermophilus elegansWyoming ground squirrel

By Sara Knoth

Geographic Range

Spermophilus elegans is made up of three, disjunct subspecies: S. e. nevadensis (found in southwestern Idaho, north-central Nevada, and formerly in extreme southeastern Oregon), S. e. aureus (found in northeastern Idaho and southwestern Montana), and S. e. elegans (found in extreme northeastern Utah, southern Wyoming, northern Colorado, and extreme western Nebraska). (Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Koeppl and Hoffmann, 1981)

Habitat

Spermophilus elegans occupies mountain meadows and talus slopes from 1,500 meters elevation to above the timberline. They are also found in sagebrush, and shrubby grasslands where they are limited to valley bottoms by other, sympatric Spermophilus species. They often are found in areas with loose sandy soil that is suitable for digging burrows. They live on upland slopes that are well drained. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Lechleitner, 1969; Wilson and Ruff, 1999)

  • Range elevation
    1524 (low) m
    5000.00 (low) ft

Physical Description

Body mass ranges from 255.15 to 396.9 grams, and length from 254 to 381 mm. The ears are larger than those of a typical ground squirrel. The eyes are outlined by a white ring. Spermophilus elegans lack the dorsal stripes and spots that are typical among ground squirrels. The dorsal fur is brown, with gray shades on the shoulders, neck and head. The sides and stomach are somewhat yellowish, especially in summer pelage. The tail is relatively short, from 59 to 79 mm, and colored like the back. These squirrels have large claws. There is only one annual molt in adults during the spring or summer. The molt varies with sex and reproductive condition. (Andelt and Hopper, 2001; Streubel, 2000; Jones Jr., et al., 1983; Wilson and Ruff, 1999)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    255.15 to 396.9 g
    8.99 to 13.99 oz
  • Range length
    254 to 381 mm
    10.00 to 15.00 in

Reproduction

Mating systems of ground squirrels are polygynous, with males competing for access to females. Mating occurs soon (within 5 days) after the emergence of females from hibernation. Females typically emerge two weeks after males. After emergence from hibernation, males aggressively defend territories against other males. Once breeding is complete they cease defending this territory. (Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Wilson and Ruff, 1999)

The specifics of mating behavior in Wyoming ground squirrels were extensively studied in a 1956 study (Denniston). Before mating, the male approaches the female and sniffs her nose. Then, he backs off and shoves dust toward her. He reapproaches the female, nibbles her neck and upper back. The female raises her tail and chirrups, as the male nuzzles her genital region. He then mounts her from behind, clasping with his forepaws. (Denniston, 1957)

Breeding normally occurs in the spring, after the squirrels emerge from hibernation. This time varies with latitude, snow conditions, and the severity of spring weather but is usually in late March or April. From 1 to 11 young are born after a gestation period of 22 to 23 days. Parturition, which lasts approximately 95 minutes, occurs in late April to early May; the young of S. elegans appear above ground by late May or early June. Breeding may be prevented by late emergence and a low body mass as a result of deep snow and extreme low temperatures. (Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Denniston, 1957; Pfeifer, 1983; Koeppl and Hoffmann, 1981; Lechleitner, 1969; Wilson and Ruff, 1999)

The young are tiny when born (6 grams). They are naked, blind, and have closed ears. The pelage grows within two weeks and, at the age of one month, the young weigh 80 to 100 grams and have adult pelage. Young are weaned between 28 and 42 days old but do not venture beyond the burrow entrance until they are 42 to 49 days old. (Jones Jr., et al., 1985; Denniston, 1957; Koeppl and Hoffmann, 1981; Wilson and Ruff, 1999)

  • Breeding interval
    Wyoming ground squirrels breed once yearly.
  • Breeding season
    Breeding occurs in early spring, a few days after females emerge from hibernation.
  • Range number of offspring
    1 to 11
  • Average number of offspring
    6-7
  • Average gestation period
    22-23 days
  • Range weaning age
    28 to 42 days
  • Range time to independence
    42 to 49 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Little is known about the parental care of Wyoming ground squirrels because the young are cared for and nursed within the burrow during the first month. It is known, however, that females are likely to live with their young in the burrow for the beginning of the summer. Towards the end of summer, the young disperse into the community, the males dispersing away from their natal range and the females staying within or near their mother's range throughout their lives. (Jones Jr., et al., 1983; Pfeifer, 1983; Wilson and Ruff, 1999)

Lifespan/Longevity

The lifespan of this species is variable. Less than one in four Wyoming ground squirrels survive their first year of life. Adults can live up to three or four years. (Jones Jr., et al., 1983)

  • Range lifespan
    Status: wild
    4 (high) years

Behavior

Spermophilus elegans are social, although females seem to be more so than males. Family groups remain together in the mother's home range but do not associate with other family groups. Males are generally solitary. They have complex burrow systems. There are several secondary entrances, and several burrows interconnect. The center of the burrow is where the nest chamber is located. In early spring males emerge from hibernation. They establish their territories, with the largest, oldest males at the center, and the younger, smaller males at the periphery. Females come out of hibernation one to three weeks after the males. Within a few days females enter estrus and mating occurs. Dominant males in the center have more than one mate, whereas less dominant males on the periphery have one or no mates. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Jones Jr., et al., 1983; Jones Jr., et al., 1985; Lechleitner, 1969)

After all females within a male's territory have been bred, the male moves from the center to the periphery of the colony. From late April throughout the rest of the active season, the females and their young occupy the center of the colony. Females are then dominant over males. By late summer, the young have grown to adult size, and have dispersed throughout and beyond the colony. (Jones Jr., et al., 1983)

Wyoming ground squirrels then spend much of their time eating in order to reach the necessary weight for hibernation. It is estimated that they spend 39% of their active time eating and 36% in watching for danger. Wyoming ground squirrels are strictly diurnal. Adult males go into hibernation in late July; adult females and juveniles hibernate in late August or early September. During hibernation they live on fat reserves and body temperatures are maintained at approximately 4 degrees Celsius. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Jones Jr., et al., 1983; Wilson and Ruff, 1999)

Home Range

Population densities can reach as high as 10 to 20 squirrels per acre. Home-range size in these dense colonies is thereby restricted, and could be as small as 25 to 50 yards. (Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Jones Jr., et al., 1983)

Communication and Perception

Wyoming ground squirrels are very vocal. They continuously call to one another during above ground activity to sound alarm when predators are present. The most used alarm call is the "chirp", which is a series of short high pitched notes. The "churr" is another call, which is longer in duration and can carry over a longer distance than the chirp. They also flick their tail as a sign of aggression. Spermophilus species also use scent marks and touching, such as "kissing" to greet others. These ground squirrels use the same suite of senses to perceive their environment. (Jones Jr., et al., 1983; Jones Jr., et al., 1985; Lechleitner, 1969)

Food Habits

The diet of Wyoming ground squirrels is mainly herbivorous. They prefer green foliage, such as grasses and leaves, although these squirrels will also eat shrubs, forbs, flowers, seeds, stems, and roots. When there is not an abundance of green foliage, Wyoming ground squirrels will eat insects, including grasshoppers, crickets, and caterpillars, as well as eggs of ground-nesting birds. Sometimes they eat carrion. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Jones Jr., et al., 1983; Jones Jr., et al., 1985; Lechleitner, 1969; Wilson and Ruff, 1999)

  • Animal Foods
  • eggs
  • carrion
  • insects
  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts

Predation

These ground squirrels are prey for hawks, coyotes, badgers, weasels, snakes, and foxes. They avoid predation through vigilance, including vocalizations used to warn conspecifics, and by seeking refuge in their burrows. (Streubel, 2000; Lechleitner, 1969)

Ecosystem Roles

Spermophilus elegans serves as a host for many parasites, including ticks, mites, lice, stomach and intestinal roundworms, and tapeworms. Their burrowing activities help to recycle nutrients and they are important prey species for small to medium-sized predators. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002; Jones Jr., et al., 1983; Jones Jr., et al., 1985)

Commensal/Parasitic Species
  • ticks
  • mites
  • lice
  • stomach and intestinal roundworms
  • tapeworms

Economic Importance for Humans: Positive

Wyoming ground squirrels are important members of the ecosystems in which they live.

Economic Importance for Humans: Negative

Wyoming ground squirrels (along with other ground squirrel species) have the potential to host fleas that transmit bubonic plague and Colorado tick fever virus. Spermophilus elegans are also agricultural pests. Their burrows can damage haying equipment and take fields out of production. Burrowing activity can also damage golf courses and lawns. (Andelt and Hopper, 2001; Streubel, 2000; "Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002)

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

Conservation Status

Spermophilus elegans is considered an unprotected nongame species. Wyoming ground squirrels have no special conservation status. They are fairly common in appropriate habitat throughout their range. (Streubel, 2000)

Other Comments

This species was formerly included in Spermophilus richardsonii. ("Comprehensive Report Species- SPERMOPHILUS ELEGANS", 2002)

Contributors

Sara Knoth (author), Michigan State University, Barbara Lundrigan (editor), Michigan State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

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.

carrion

flesh of dead animals.

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.

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.

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.

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.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

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

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.

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

2002. "Comprehensive Report Species- SPERMOPHILUS ELEGANS" (On-line ). NatureServe Explorer: An online encyclopedia of life. Accessed 03/02/03 at http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Spermophilus+elegans.

Andelt, W., S. Hopper. 2001. "Managing Wyoming ground squirrels" (On-line ). Accessed 03/02/03 at http://www.ext.colostate.edu/PUBS/NATRES/06505.html.

Denniston, R. H. 1957. Notes on breeding and Size of Young in the Richardson Ground Squirrel. Journal of Mammalogy, Vol. 38: 414-416.

Jones Jr., J. K., D. M. Armstrong, J. R. Choate. 1985. Guide to Mammals of the Plains States. Lincoln: University of Nebraska Press.

Jones Jr., J. K., D. M. Armstrong, R. S. Hoffmann, C. Jones. 1983. Mammals of the Northern Great Plains. Lincoln: University of Nebraska Press.

Koeppl, J. W., R. S. Hoffmann. 1981. Comparative Postnatal Growth of four Ground Squirrel Species. Journal of Mammalogy, Vol. 62: 41-57.

Lechleitner, R. R. 1969. Wild Mammals of Colorado: Their Appearance, Habits, Distribution, and Abundance. Boulder, CO: Pruett Publishing Co..

Pfeifer, S. 1983. Variability in Reproductive Output and Success of <<Spermophilus elegans>> Ground Squirrels. Journal of Mammalogy, Vol. 63: 284-289.

Streubel, D. 2000. "*Spermophilus elegans*" (On-line ). Digital Atlas of Idaho. Accessed 03/02/03 at http://imnh.isu.edu/digitalatlas/bio/mammal/Rod/squir/wygr/wgsqfrm.htm.

Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington, D.C.: The Smithsonian Institution Press.

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