Spermophilus franklinii - Franklin’s Ground Squirrel

Geographic Range:

Nearctic: Franklin’s ground squirrels range in distribution east to Indiana and Illinois, west to North Dakota and Kansas and as far north as southern Ontario and central Manitoba and Alberta.  In Wisconsin they cover one half of the state at a diagonal from the north at Superior and south to Racine (Lewis & Rongstad 1992).

Physical Description:

Except for the prominent white eye-ring, Franklin’s ground squirrels resemble Eastern gray squirrels at a distance (Wilson & Ruff, 1999).  They have a gray head that grades into a brown color with indistinct buff and black barring.  The chest and belly are buffy-white to gray and the tail is gray like the head. They have a slender and elongated body that measures 350-420mm (14-17in).  They have a shorter and less bushy tail than the gray squirrel, measuring 125- 160mm (4.9-6.3 in), which accounts for less than 40% of their total length.  They have smaller and more rounded ears than a gray squirrel measuring 16-18mm (0.6-0.7in) in height and weighing 370-500g (13.1-17.6 oz).  This includes average emergent weights of 410g for males and 351g  for females. (Kurta, 1994; Sowls, 1948).

Life Cycle and Reproduction:

Franklin ground squirrel populations peak every four to six years due to fluctuations in climatic extremes, infertility, and disease (Sowls, 1948).

Erlien and Tester (1984), also attribute this cycle to a possible correlation between Snowshoe hare cycles, with a time-lagging decline of Franklin’s ground squirrel populations corresponding to increases in hare populations.

The Franklin’s ground squirrel spends 7-8 months, from mid to late August through April, hibernating in an underground burrow each year.  Males emerge first and mating occurs soon after the females appear.  Gestation is from 26-28 days and litter sizes vary from 4-11 but most often are 7-8.  Young are altricial and leave the den after 30 days.  Adults produce only one litter per year and youngsters become sexually mature the spring following their birth  (Kurta, 1994; Wilson & Ruff, 1999; Nowak, 1991). 

Habitat:

Franklin’s ground squirrel can be found in areas of tall grass prairie.  It prefers grass of intermediate height, tall enough to hide the animal when on all four feet but low enough to see over when standing upright on the hind legs.  It lives along forested grassland edges, fencerows bordering cropland, tall grasses along railroads and marshland edges.  They sometimes use abandoned burrow systems of northern pocket gophers during the day as well as at night, this also influences above ground movements during the day (Kurta, 1994; Lewis & Rongstad, 1992; Choromanski-Norris et al. 1989).

Food Habits:

Diet consists of fruits, seeds and vegetable fibers from plants such as grass, thistle, dandelion, clover, and black berry, along with cultivated grains and garden vegetables. Up to one third of its diet consists of animal flesh, mainly insects.  Caterpillars, grasshoppers, crickets, and ants are the most common prey but they will occasionally consume a frog, toad, nestling bird, bird egg or mouse.  However, it has been found that Franklin’s ground squirrel is a big predator of duck nests, including the eggs and young waterfowl (Sabine, 1912; Kurta, 1994; Sowls, 1948).

Ecology and Behavior:

Franklin ground squirrels are diurnal mammals that are fairly sedentary and rarely venture more than 100m (330 ft) from their burrows.  They stay underground quite a lot and only spend approximately 10% of their life above ground (Sowls, 1948).  It can climb trees but mostly forages for food on the ground.  (Nowak, 1991; Kurta, 1994).

Franklin ground squirrels are relatively inconspicuous and they immediately seek refuge in their burrows when alarmed.   Known predators are Red-Tailed Hawk, Red Fox, Badger, Coyote, Skunk, Mink, Long-Tailed Weasels and possibly owls (Baker, 1983).  They are less social than other ground squirrel species but do live in loose aggregations.  They are known to make a variety of calls that are described as being clear and musical but the meaning of these calls is not known.  Sometimes their distinctive call causes them to be known as whistle pigs (Sowls, 1948).

Remarks:

Was named after the Arctic explorer, Sir John Franklin.

Original name was Arctomys franklinii, Sabine, 1822

Other names; Myotis thysanodes, Citellus franklinii.

Gray gophers, Franklin’s Prairie squirrel, Gray Prairie squirrel, or whistling squirrel.

Franklin’s ground squirrels can swim if they have to.

Sardines are used as bait to live trap a Franklin’s ground Squirrel.

Literature Cited:

Choromanski-Norris, Jane; Erik K. Fritzell; Alan B. Sargeant. 1989. Movements and Habitat Use of Franklin’s Ground Squirrels In Duck-Nesting Habitat.  Journal of Wildlife Management, 53(2): 324-331.

_____.   1986. Seasonal Activity Cycle And Weight Changes of The Franklin’s Ground Squirrel.  American Midland Naturalist, 116(1): 101-107.

Cory, Charles B. 1912. The Mammals of Illinois and Wisconsin.  Field Museum of Natural History. 153(XI): 144-149.

Eagle, T.C.; J. Chromanski-Norris; V.B. Kuechle. 1984. Implanting Radio Transmitters in Mink and Franklin’s Ground Squirrels. Wildlife Society Bulletin. 12:180-184.

Erlien, D. A.; J.R. Tester. 1984.  Population Ecology of Sciurids in Northwestern Minnesota.  The Canadian Field-Naturalist. 98:1-6.

Franklin’s Ground Squirrel.  http://www.ku.edu/-mammals/sperm-frank.html.

Franklin’s Ground Squirrel: vanishing prairie hibernator.  Chicago Wilderness Magazine. 2002.  http://chicagowildernessmag.org/issues/winter2002/franklins.html

Iverson, S. L.; B.N. Turner. 1972.  Natural History of a Manitoba Population of Franklin’s Ground Squirrels.  The Canada Field Naturalist. 86:145-149.

Kurta, Allen.1994. Mammals of the Great Lakes Region, The University of Michigan Press. Ann Arbor. p. 118-120.

Lewis, T. L.; O. J. Rongstad. 1992. The Distribution Of Franklin’s Ground Squirrel in Wisconsin and Illinois.  Wisconsin Academy of Sciences, Arts and Letters. Transactions, 80:57-62.

Murie, Jan. O. 1973. Population characteristics and phenology of a Franklin ground squirrel (Spermophilus franklinii) colony in central Alberta.  American Midland Naturalist, 90: 334-340.

Nowak, R. M. 1991.  Walker’s Mammals of the World,  Johns Hopkins University Press, Baltimore, MD.

Sowls, Lyle K. 1948. The Franklin ground squirrel, Citellus franklinii (Sabine), and its relationship to nesting ducks.  Journal of Mammalogy,  p.113-137.

Wilson, D. E.; Sue Ruff, ed., 1999. The Smithsonian Book of North American Mammals.  Smithsonian Institution Press, Washington, D.C. p. 282-283.

Reference written by Kristen Cragin, Biology 378 student.  Edited by Christopher Yahnke.
Page last updated 4-29-04.