Franklin's ground squirrel (Spermophilus franklinii)

Also known as: bush gopher, Franklin ground squirrel, gray gopher, gray ground squirrel, gray souslik, gray-cheeked squirrel, grey American marmot, line-tailed squirrel, prairie squirrel, scrub gopher, spermophile de Franklin, whistling ground squirrel
Synonyms: Arctomis franklini, Arctomys franklinii, Citellus franklini, Spermophilus franklini
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderRodentia
FamilySciuridae
GenusSpermophilus (1)
SizeMale total length: 37.2 - 41.2 cm (2)
Female total length: 35.9 - 40 cm (2)
Male tail length: 11.3 - 15.3 cm (2)
Female tail length: 12 - 14.9 cm (2)
Male weight: 326 - 950 g (2)
Female weight: 308 - 760 g (2)

Franklin’s ground squirrel is classified as Least Concern (LC) on the IUCN Red List (1).

Franklin’s ground squirrel (Spermophilus franklinii) is, like other members of its genus, a mainly terrestrial rodent with a relatively short, well-furred tail, short legs, and large cheek pouches for carrying food (3).

The upperparts of Franklin’s ground squirrel are brownish-grey and speckled with dark flecks, particularly on the hind quarters. The head is usually slightly darker and greyer than the rest of the body, while the sides of the body are paler and there is a yellowish tone on the rump (2) (4) (5). The thinner fur on the underparts is usually light yellowish-white to grey or buff (2) (5) (6). Franklin’s ground squirrel has a greyish to black tail, which has pale flecks and becomes blacker towards the tip (2) (4) (5).

The male Franklin’s ground squirrel is typically larger and heavier than the female (2). This species can be distinguished from the closely related thirteen-lined ground squirrel (Spermophilus tridecemlineatus) by its larger size and lack of stripes (4) (5). Franklin’s ground squirrel also resembles the eastern gray squirrel (Sciurus carolinensis) in appearance, but has a shorter, less bushy tail, as well as shorter, rounder ears, longer and straighter claws, and cheek pouches (2) (4) (5) (6).

Ground squirrels (Spermophilus species) generally use a wide range of vocalisations, including trills, squeaks and chirps (3). Franklin’s ground squirrel tends to be more vocal than other ground squirrels, producing bird-like twitters as well as a very clear, musical whistle (4) (5), which gives this species its alternative name of ‘whistling ground squirrel’ (5).

Franklin’s ground squirrel is found from the central United States northwards into Canada. It occurs from Kansas, Missouri and Illinois, north through Nebraska, Iowa, Indiana, Wisconsin, Minnesota, South Dakota and North Dakota in the U.S., to Alberta, Saskatchewan, Manitoba and Ontario in Canada (1) (2) (4) (5).

A primarily terrestrial species (2) (3) (5), Franklin’s ground squirrel typically inhabits tall grass prairies, although it may also be found in fields, hedgerows, marsh edges, forest-field edges, and along roadsides and railroad rights-of-way (strips of land owned by railroads), if these are un-mowed (1) (2) (5) (6).

Franklin’s ground squirrel tends to avoid short-grass habitats, such as prairies that are grazed or mowed (1) (2). The distribution of this species appears to be limited by the availability of cover and of soil that is suitable for burrowing (1).

Franklin’s ground squirrel is active during the day (1) (2) (3), particularly when the weather is bright and sunny (4) (5). Although mainly ground-dwelling, this species is also able to climb bushes and trees (2) (3) (4) (5).

Franklin’s ground squirrel has a varied diet which comprises a range of plant and animal material, including seeds, roots, shoots, leaves, buds, flowers, bulbs, vegetables and fruits, as well as insects, amphibians, fish, young birds, bird eggs and small mammals (2) (3) (4) (5) (6) (7). It will even eat young rabbits and other ground squirrels, and has been known to kill adult ducks and poultry (2) (4) (5) (7). Animal matter usually makes up around a third of the overall diet of this species (5) (6) (7).

Only spending around ten percent of its time above ground (1) (5) (7), Franklin’s ground squirrel lives the rest of its life in an underground burrow which it typically digs into a bank, hill or other steep slope, in well-drained soil (1) (2) (6). The burrow may have two or three entrances (2) and many branches, one of which has a nesting area lined with dried plant material (2) (6). Other branches may be used to store food or as latrines (2) (5).

Franklin’s ground squirrel is one of the least social members of its genus (2), usually living in small, loose colonies which rarely number over 10 to 12 individuals (4) (5). Its populations appear to fluctuate, peaking around every four to six years (1) (2) (5) (6), and this species will often stay in an area for a short period of time before disappearing and setting up a colony elsewhere (4) (5).

During the summer months, Franklin’s ground squirrel accumulates a thick layer of body fat to see it through the long winter hibernation period (2) (5). Individuals usually enter hibernation around late September (1) (4) (6), although in some northern areas they may become inactive as early as July (8). Males are the first to enter hibernation, while juveniles are the last, as they need extra time to build up sufficient fat reserves (2) (4) (5) (6). Several Franklin’s ground squirrels may hibernate together in the same burrow (2) (5).

The hibernation period of Franklin’s ground squirrel lasts around seven to eight months, with males not emerging again until late March or April. The female Franklin’s ground squirrels emerge from hibernation around one to two weeks after the males (2) (4) (5) (6) (9), but juveniles may not appear until as late as June or July (9). Breeding begins immediately after emergence, with male Franklin’s ground squirrels establishing dominance hierarchies (2), and mating occurring as soon as the females appear (2) (4) (5) (6).

The female Franklin’s ground squirrel gives birth to a single litter of between 5 and 11 young, usually in May or June, after a gestation period of 28 days (1) (2) (4) (5) (6). The young are born naked and blind (2) (5), and spend a month inside the burrow before emerging above ground (4) (5). Weaning takes place at about 40 days old (1) (4). After remaining with the female for several more weeks, the young Franklin’s ground squirrels disperse, and they develop rapidly, nearing full adult size by the autumn (4) (5) (7).

Both the male and female Franklin’s ground squirrel become sexually mature in the first spring following their birth (5) (6). Females may live for up to five years, but males usually only live for one to two years (2). Franklin’s ground squirrel may fall prey to a number of predators, including foxes, coyotes (Canis latrans), American badgers (Taxidea taxus), hawks, weasels, skunks and snakes (2) (4) (5) (6) (7), but failure to store enough body fat for hibernation may also be an important cause of mortality in juveniles (6).

Although Franklin’s ground squirrel has a widespread distribution (1), it appears to be declining in some parts of its range, particularly in eastern states such as Indiana, Wisconsin and Illinois (1) (4) (10) (11) (12). In the U.S., the Franklin’s ground squirrel population has been highly fragmented and is often restricted to linear habitats (long, thin strips of habitat) and small patches of prairie (1). However, in Canada, larger areas of suitable habitat have been preserved, and the Franklin’s ground squirrel population appears to be more secure (1).

The main cause of the decline in Franklin’s ground squirrel is believed to be the destruction and fragmentation of tall grass habitats, due for example to agricultural expansion and urban development (1) (3) (10). Although it is often found along railroad rights-of-way, changing management techniques, such as frequent mowing and the use of herbicides, may be making many of these unsuitable for this species. Many rights-of-way are also being abandoned, leading to the encroachment of woody vegetation (1).

Another threat to Franklin’s ground squirrel comes from its extermination as a suspected agricultural pest, although there is little evidence that this species causes significant crop damage (1). Franklin’s ground squirrel has also been persecuted as a predator of ducks and their eggs (1). However, it is only thought to cause significant losses in certain locations or during certain years when it is particularly abundant (5) (7).

Franklin’s ground squirrel may be further affected by poisoning by pesticides or by poisons used to control the plains pocket gopher (Geomys bursarius) (1) (12). It may also be killed on roads (4). The fragmentation and isolation of its populations could potentially hinder the dispersal of Franklin’s ground squirrel and so lead to inbreeding (1).

Franklin’s ground squirrel occurs in many protected areas throughout its range (1). Recommended conservation measures for this species include further studies into its populations, genetics and habitat requirements (1) (10), as well as cooperating with railroads to reduce mowing and herbicide treatment along rights-of-way (1) (2) (10). Abandoned rights-of-way inhabited by Franklin’s ground squirrel should be acquired and preserved, especially where they link larger areas of habitat (1).

The extent to which Franklin’s ground squirrel is controlled by farmers and ranchers should be investigated, and programmes designed that are compatible with the needs of both farmers and ground squirrels. The effects of the poisoning of gophers on Franklin’s ground squirrel should also be assessed (1).

Other conservation measures recommended for Franklin’s ground squirrel include educating the public about the species and initiating a captive breeding and reintroduction programme (1).

Find out more about Franklin’s ground squirrel:

More information on the conservation of North American rodents:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (January, 2012)
    http://www.iucnredlist.org/
  2. Ostroff, A.C. and Finck, E.J. (2003) Spermophilus franklinii. Mammalian Species, 724: 1-5. Available at:
    http://www.science.smith.edu/msi/pdf/724_Spermophilus_franklinii.pdf
  3. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
  4. Whitaker Jr, J.O. and Hamilton Jr, W.J. (1998) Mammals of the Eastern United States. Cornell University Press, Ithaca.
  5. Schwartz, C.W. and Schwartz, E.R. (2001) The Wild Mammals of Missouri. Second Revised Edition. University of Missouri Press, Columbia, Missouri.
  6. Kurta, A. (1995) Mammals of the Great Lakes Region. University of Michigan Press, Ann Arbor, Michigan.
  7. Sowls, L.K. (1948) The Franklin ground squirrel, Citellus franklinii (Sabine), and its relationship to nesting ducks. Journal of Mammalogy, 29(2); 113-137.
  8. Murie, J.O. (1973) Population characteristics and phenology of a Franklin ground squirrel (Spermophilus franklinii) colony in Alberta, Canada. American Midland Naturalist, 90(2): 334-340.
  9. Choromanski-Norris, J., Fritzell, E.K. and Sargeant, A.B. (1986) Seasonal activity cycle and weight changes of the Franklin’s ground squirrel. American Midland Naturalist, 116(1): 101-107.
  10. Johnson, S.A. and Choromanski-Norris, J. (1992) Reduction in the eastern limit of the range of the Franklin’s ground squirrel (Spermophilus franklinii). American Midland Naturalist, 128(2): 325-331.
  11. Lewis, T.L. and Rongstad, O.J. (1992) The distribution of Franklin’s ground squirrel in Wisconsin and Illinois. Transactions of the Wisconsin Academy of Sciences, Arts and Letters, 80: 57-62.
  12. Martin, J.M., Heske, E.J. and Hofmann, J.E. (2003) Franklin’s ground squirrel (Spermophilus franklinii) in Illinois: a declining prairie mammal? American Midland Naturalist, 150(1): 130-138.