Urocitellus townsendii

Townsend's Ground Squirrel (Urocitellus townsendii)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Sciuromorpha
Family:	Sciuridae
Subfamily:	Xerinae
Tribe:	Marmotini
Genus:	Urocitellus
Binomial details
Urocitellus townsendii (Bachman, 1839)
Other resources
Full taxonomic details at MDD

The Townsend's Ground Squirrel (Urocitellus townsendii) is a small species of ground squirrel with short ears. It is restricted to a relatively small area north of the Columbia River in Washington.

Description

The following description from Rickart (1987) refers to Urocitellus townsendii sensu lato (townsendii complex) before the species was fully split out so the description may or may not be restricted to the species as it it is currently defined: "The general dorsal coloration is pale smoke gray, often washed with pinkish buff... Worn pelage is often brownish. Underparts are creamy white washed with pinkish buff (Howell, 1938)." The dorsal pelage is unspeckled.

Townsend's Ground Squirrel (Urocitellus townsendii) photographed by Dasha Gudalewicz in Washington state.

Townsend's Ground Squirrel (Urocitellus townsendii) photographed by Yinan Li in Yakima County, Washington.

Museum specimens

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897.

External measurements

Museum help needed!

Skull

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897. Dorsal view of the skull.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897. Ventral view of the skull.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897. Lateral view of the skull.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897. Dorsal view of the mandible.

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  Holotype: USNM 89331. Urocitellus townsendii townsendii. Adult male. Mabton, Yakima County, Washington. Collected 16 July 1897. Lateral view of the left mandible.

Taxonomic notes

From Cole and Wilson (2009): "Howell (1938) revised the genus Spermophilus and designated canus, mollis, vigilis, and artemesiae, a taxon restricted to north of the Snake River in Idaho, as subspecies of townsendii. Based on his study of karyotypes, Nadler (1968) separated U. townsendii in Washington east and north of the Yakima River from those animals west and south of the river (Verts and Carraway 1998). Nadler (1968) demonstrated differences in karyotypes among some of these races, but Hall (1981) and Rickart (1987) treated the group as a single species (U. townsendii). Nadler (1968) and Rickart et al. (1985) examined representative individuals of the subspecies of the U. townsendii complex cytologically. Hoffmann et al. (1993) considered the U. townsendii complex to consist of 3 species: U. townsendii, U. canus (including canus and vigilisi), and U. mollis (including artemesiae, idahoensis, mollis, and nancyae). Thorington and Hoffmann (2005) agreed with this taxonomy with the exception of reallocating nancyae as a subspecies of townsendii."

Similar species

The range of Urocitellus townsendii abuts that of the Columbian Ground Squirrel (Urocitellus columbianus) to the east and the Belding's Ground Squirrel (Urocitellus beldingi) to the south, but the Columbia River appears to be a major biogeographic barrier.

Comparison with Urocitellus canus and Urocitellus mollis

The range of Urocitellus townsendii does not abut that of the Merriam's Ground Squirrel (Urocitellus canus) or Piute Ground Squirrel (Urocitellus mollis), but a comparison is provided as these species were formerly considered subspecies of townsendii and are nearly identical in appearance. Locality information is important for distinguishing these species. From Cole and Wilson (2009): "Urocitellus canus is not distinguishable from U. townsendii and U. mollis using external characteristics (Kays and Wilson 2002; Rickart 1999). These species are relatively small, have short, inconspicuous ears, short, thin tails, and their pelage is unmarked."

Species	Subgroup	Total length	Greatest length of skull	Measurement reference
Urocitellus canus	small-eared	typically <250 mm	34.6–38.7 mm (condylobasal length)	Cole and Wilson (2009)
Urocitellus mollis	small-eared	188 mm (holotype)	33.4–38.6 mm (condylobasal length)	McLean (2025)
Urocitellus townsendii	small-eared	Museum help needed	Museum help needed

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  Merriam's Ground Squirrel (Urocitellus canus) photographed by Christopher Lindsey in Baker County, Oregon. This is a small-eared species. It is a gray ground squirrel with dorsal pelage that lacks spots or flecks. The sides of the head and the hind legs are tinted with pinkish to reddish buff.

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  Piute Ground Squirrel (Urocitellus mollis) photographed by Caleb Stroh in Box Elder County, Utah. This is a small-eared species. The upper parts are finely variegated silvery-gray, light yellowish-brown, and black; these colors are uniformly mixed throughout, without any indication of spots.

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  Townsend's Ground Squirrel (Urocitellus townsendii) photographed by Yinan Li in Yakima County, Washington. This is a small-eared species with dorsal coloration that lacks spots.

Comparison with Urocitellus washingtoni

The distinct dorsal spotting of the Washington Ground Squirrel (Urocitellus washingtoni) helps to distinguish it from Urocitellus townsendii."

Species	Subgroup	Total length	Greatest length of skull	Measurement reference
Urocitellus townsendii	small-eared	Museum help needed	Museum help needed
Urocitellus washingtoni	small-eared	185–245 mm	35.0–41.8 mm	Rickart and Yensen (1991)

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  Townsend's Ground Squirrel (Urocitellus townsendii) photographed by Yinan Li in Yakima County, Washington. This is a small-eared species with dorsal coloration that lacks spots.

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  Washington Ground Squirrel (Urocitellus washingtoni) photographed by TonyP PNW in Washington state. This is a small-eared species. The dorsum is flecked with grayish-white spots.

References

Cole FR, Wilson DE. 2009. Urocitellus canus (Rodentia: Sciuridae). Mammalian Species (834):1-8. https://doi.org/10.1644/834.1

Hall ER. 1981. The mammals of North America. 2 vols. New York (NY, USA): John Wiley and Sons.

Hoffman RS, Anderson CG, Thorington Jr RW, Heaney LR. 1993. Family Sciuridae. Pp. 419-466 in Mammal species of the world: a taxonomic and geographic reference (D. E. Wilson and D. M. Reeder, eds.). 2nd ed. Washington DC (USA): Smithsonian Institution Press.

Howell AH. 1938. Revision of the North American ground squirrels, with a classification of the North American Sciuridae. North American Fauna 56:1-25.

Nadler CF. 1968. The chromosome of Spermophilus townsendii (Rodentia: Sciuridae) and a report of a new subspecies. Cytogenetics 7:144-157. https://doi.org/10.1159/000129978

Rickart EA. 1987. Spermophilus townsendii. Mammalian species (268):1-6. https://doi.org/10.2307/0.268.1

Verts BJ, Carraway LN. 1998. Land mammals of Oregon. Berkeley (CA, USA): University of California Press.