Spermophilus frankliniiFranklin's ground squirrel

Geographic Range

Franklin's ground squirrels live in the northern part of the American tallgrass prairie. They occur from the southwest of Ontario west to central Manitoba, south through central North Dakota and central Kansas. They are found as far east as west-central Indiana, and northwest to the Lake Michigan shore in the Michigan City-Chicago area. They also occur through southern Wisconsin and central Minnesota. (Baker, 1983)

Habitat

Franklin's ground squirrel can be found in the tallgrass prairie areas of the northcentral United States and adjacent parts of Canada. They live at the border between grassy areas and woody vegetation because of the diverse food sources available (Baker, 1983). These squirrels are not often seen because of their preference for densely vegetated areas.

Physical Description

Franklin's ground squirrels are larger than the average ground squirrel. They have a slender and elongated body that measures 355 to 410 mm in total length, tail length measures 120 to 158 mm. The pelage is and short salt-and-pepper colored and the tail is bushy. The head and tail are grayish as a result of of alternating bands of black and white on the individual hairs. The feet are pale gray and the ears are short and ovate. Males are heavier than females and winter and summer weights vary significantly. Males range from 370 to 500 g in spring, upon emerging from hibernation to 570 to 950 g in late fall, before entering hibernation. Female weights range from 340 to 425 g in spring and 500 to 760 g in fall. (Baker, 1983; Nowak,1991)

  • Range mass
    340 to 950 g
    11.98 to 33.48 oz
  • Average basal metabolic rate
    2.19 W
    AnAge

Reproduction

There is a great deal of rivalry during courtship among males in their pursuit of a female. Musky discharges from the anal glands play a role in the sex attracting process. The mating phase of the reproductive process is completed by mid-April. The gestation period is about 28 days. The young are born in May or June. Franklin's ground squirrels have one litter annually, which contains from 5-10 babies (average 7). At birth the young are naked and blind but at ten days old fuzzy hair appears. At 20 days their eyes open and they can emit whistle calls. At 30 days the young venture outside and at 40 days the weaning process is completed. By the time winter comes, the young are almost adult size. The young squirrels are not interested in mating until after hibernation at the end of their first year. (Baker, 1983; Nowak, 1991)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Average number of offspring
    7.5
    AnAge
  • Average gestation period
    28 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    327 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    327 days
    AnAge

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    7.2 years
    AnAge

Behavior

Franklin's ground squirrels lack the noisy and "curious" actions that are apparent in their relatives, they are relatively inconspicuous. Franklin's ground squirrels don't usually stand in an upright position, as their relatives do when alarmed. Instead they immediately seek refuge in their burrows.

Franklin ground squirrels are most active on bright, sunny days. They are estimated to spend approximately 10% of their time above ground. They usually inhabit an area that is about 300 feet in diameter. They dig ground burrows that may extend as much as 8 ft underground, and that have several branches and openings. Burrows can be found in tall grass or weed cover, on rocky slopes, on railroad embankments, and under logs, rocks, and fences.

Franklin's ground squirrels can swim and climb trees. They are less social than other ground squirrel species but do often live in loose aggregations.

They have been know to make a variety of calls, suggesting gregarious relationship. The meaning of the calls is not know, but they are described as being clear and musical.

Franklin's ground squirrels put on a heavy layer of fat in the late summer for sustenance during winter hibernation. By late September, each squirrel has selected an underground spot for hibernation. It hibernates through the winter and emerges in late March or early April. (Baker, 1983; Nowak, 1991)

Communication and Perception

Food Habits

Franklin's ground squirrels' diet consists of tough vegetable fibers and hard-shelled seeds and fruits. They feed on the vegetative parts of grasses, clovers, mustard, dandelion, strawberry, thistle and other plants. Seeds and fruits as well as cultivated crops such as corn, oats, wheat and a variety of garden vegetables are also part of their diet. Franklin's ground squirrels also eat some animal material, including beetles, caterpillars, grasshoppers, crickets, ants, small birds, ducks, deer mice, frogs, toads, birds' or ducks' eggs, and even other ground squirrels. (Baker, 1983)

Economic Importance for Humans: Positive

Franklin's ground squirrels disperse the seeds of many plant species.

Economic Importance for Humans: Negative

Franklin's ground squirrel are sometimes considered nuisances to prairie farmers and gardeners. In years with a high population of Franklin's ground squirrels, they have been seen as serious competitors for agriculturists' grains and vegetables (Jones and Birney, 1988; Baker, 1983)

Conservation Status

Franklin's ground squirrels are relatively rare throughout their range, though they may be locally abundant. In recent decades populations throughout the midwestern United States have declined dramatically. They are now listed as endangered in Iowa, a species of special concern in Wisconsin, rare in Iowa, and populations in Illinois are in decline.

(Pergams, 2002)

Other Comments

Franklins' ground squirrel population peaks occur every four to six years. The population grows from eight squirrels per acre to as many as 30 squirrels per acre.

Franklin's ground squirrels encounter many predators, including the red-tailed hawk, red fox, badger, coyote, striped skunk, mink, and long-tailed weasel (Baker, 1983).

Contributors

Eric Olson (author), University of Michigan-Ann Arbor.

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

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

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.

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.

sexual

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

tactile

uses touch to communicate

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.

References

Jones, Jr., J. K. and E. C. Birney. 1988. Handbook of Mammals of the North-Central States. Univ. of Minn. Press, Minneapolis.

Nowak, R. M. 1991. Walker's Mammals of the World, The Johns Hopkins Press.

Baker, R. 1983. Michigan Mammals. MSU Press.

Pergams, O. March 29, 2002. "Franklin's Ground Squirrel Conservation Page" (On-line). Accessed August 23, 2002 at http://icarus.uic.edu/~operga1/fgs.html.