Urocitellus washingtoni
| Washington Ground Squirrel
(Urocitellus washingtoni) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Sciuromorpha |
| Family: | Sciuridae |
| Subfamily: | Xerinae |
| Tribe: | Marmotini |
| Genus: | Urocitellus |
| Binomial details | |
| Urocitellus washingtoni (A. H. Howell, 1938) | |
| Other resources | |
| Full taxonomic details at MDD | |
The Washington Ground Squirrel (Urocitellus washingtoni) is one of smallest species of ground squirrels. They inhabit dry, open sagebrush or grassland habitat in the southeastern part of Washington state and the Blue Mountains in northeastern Oregon (Rickart and Yensen, 1991).
Description
From Rickart and Yensen (1991): "Dorsal coloration of spring pelage is pale smoke-gray, faintly washed with pinkish-buff. Worn pelage is more brown. The dorsum is flecked with grayish-white spots that are roughly square and 3-4 mm in breadth. Underparts are grayish-white washed with pinkish-buff. The feet are white, tinged with pinkish-buff. The tail is gray mixed with fuscous above, pinkish-cinnamon beneath, and edged with buffy white (Howell, 1938).
Museum specimens
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Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891.
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
| Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
|---|---|---|---|---|---|---|
| rangwide | Rickart and Yensen (1991) from Howell (1938) | 185–245 | 32–65 | 30–38 |
Skull
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Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. Dorsal view of the skull. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. Ventral view of the skull. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. Lateral view of the skull. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. Dorsal view of the left mandible. -
Holotype: USNM 27948/40068. Urocitellus washingtoni. Adult male. Touchet, Walla Walla County, Washington. Collected 18 May 1891. Lateral view of the left mandible.
Similar species
Comparisons with sympatric congeners are provided below.
Comparison with Urocitellus beldingi and U. columbianus
Urocitellus washingtoni is smaller in size (length of hind foot <39 mm) than Belding's Ground Squirrel (Urocitellus beldingi) and Columbian Ground Squirrel (Urocitellus columbianus) (Rickart and Yensen, 1991).
| Species | Subgroup | Total length | Greatest length of skull | Measurement reference |
|---|---|---|---|---|
| Urocitellus beldingi | big-eared | 230–300 mm | 41.3–46.3 mm | Jenkins and Eshelman (1984) |
| Urocitellus columbianus | big-eared | 325–410 mm | 51.7 mm (ssp. ruficaudus) | Elliot and Flinders (1991) |
| Urocitellus washingtoni | small-eared | 185–245 mm | 35.0–41.8 mm | Rickart and Yensen (1991) |
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Belding's Ground Squirrel (Urocitellus beldingi) photographed by Roger Woodruff in Tuolumne County, California. This is a big-eared species with a mid-dorsal area often is darker reddish-brown than the sides, although the conspicuousness of this trait varies geographically. -
Columbian Ground Squirrel (Urocitellus columbianus) photographed by Andrey Atuchin in Kananaskis, Alberta, Canada. This is a big-eared species. It is one of the largest and most richly colored species in the genus Urocitellus. -
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.
Comparison with Urocitellus townsendii
From Rickart and Yensen (1991): "Its distinct dorsal spotting, more bushy tail, and larger, narrower skull distiguish it from 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 Dasha Gudalewicz in Washington state. This is a small-eared species with dorsal coloration that lacks spots. -
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
Howell AH. 1938. Revision of the North American ground squirrels, with a classification of the North American Sciuridae. North American Fauna 56:1-25.
Rickart EA, Yensen E., 1991. Spermophilus washingtoni. Mammalian Species (371):1-5. https://doi.org/10.2307/3504272