Neotamias quadrivittatus

Colorado Chipmunk
(*Neotamias quadrivittatus*)
Colorado Chipmunk (Neotamias quadrivittatus)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Sciuromorpha
Family:	Sciuridae
Subfamily:	Xerinae
Tribe:	Tamiini
Genus:	Neotamias
Binomial details
	Neotamias quadrivittatus (Say in James, 1823)
Other resources
	Full taxonomic details at MDD

Description

From Armstrong (2010): "The Colorado chipmunk is large, similar in size to the Uinta chipmunk. The central dorsal stripe is black and very distinct, whereas the dark lateral stripes are more reddish brown. White lateral stripes are also usually well defined. In animals with recently molted pelage the dorsal background color is bright reddish brown paling to orange-buff on the sides. The ventral color is pale gray."

From Best et al. (1994): "quadrivittatus is medium-sized for the genus. In summer pelage (June-September), the head is cinnamon and shades on the crown to pale drab or smoke gray. The stripe through the eye is fuscous black and bordered with cinnamon. Other facial stripes are rather narrow and mixed with cinnamon and fuscous. The sides of the nose and sometimes of the face are washed with clay color. The ears are fuscous or fuscous black and edged on the anterior margin with ochraceous tawny and broadly margined posteriorly with grayish white; postauricular patches are grayish white. The dark dorsal stripes are black and margined with ochraceous tawny; the outer pair may be mostly tawny. The lateral stripe is fuscous, fuscous black, or tawny. The pale dorsal stripes are grayish white; the outer pair usually is creamy white. The sides are ochraceous tawny and shade on the shoulders to cinnamon. The rump and thighs are cinnamon buff mixed with smoke gray. The front feet are cinnamon buff and the hind feet are pinkish buff or pinkish cinnamon. Dorsally, the tail is fuscous black (bases of the hairs are cinnamon) and overlaid with pinkish buff. Ventrally, the tail is ochraceous tawny or tawny, bordered with fuscous black, and edged with pinkish buff; underparts are creamy white. In winter pelage (October-December), coloration is similar to summer pelage, but the median pair of pale dorsal stripes is more grayish (color nomenclature follows Ridgway, 1912 - Howell, 1929)."

Museum images

Holotype: USNM 530290. Neotamias quadrivittatus australis. Adult male. Aguirre Springs, Dona Ana County, New Mexico. Collected 12 September 1978.
Holotype: USNM 17144/[24077]. Neotamias quadrivittatus gracilis. Female. San Pedro, Socorro County, New Mexico. Collected 4 July 1889.
Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909.

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
Arizona (Apache Co.)	Hoffmeister (1986)	205–245 (n=22)	80–107 (n=22)	32–35 (n=22)
Arizona (Navajo Co.)	Hoffmeister (1986)	210–230 (n=19)	80–105 (n=19)	32–34 (n=19)
Colorado	Armstrong et al. (2010)	200–245	90–110	31–37	20–23	45–90

Skull

Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909. Dorsal view of the skull.
Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909. Ventral view of the skull.
Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909. Lateral view of the skull.
Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909. Dorsal view of the mandible.
Holotype: USNM 154163. Neotamias quadrivittatus animosus. Adult female. Irwin Ranch, Las Animas County, Colorado. Collected 29 April 1909. Lateral view of the left mandible.

Similar species

Comparison with Neotamias minimus

From Best et al. (1994): "Compared with minimus, quadrivittatus has bright orange on the shoulders. In addition, quadrivittatus has three prominent dark dorsal stripes while minimus has five (Hoffmeister, 1986). The ears and hind feet of minimus are smaller (Howell, 1929). Where quadrivittatus and minimus occur together, quadrivittatus is recognized by its larger size and affinity for rocky sites instead of wooded habitats. The elevational range of quadrivittatus on the eastern slope of the Rocky Mountains is more restricted than that of minimus (Armstrong, 1972)."

USNM 17144/[24077]. Colorado Chipmunk (Neotamias quadrivittatus). Female. San Pedro, Socorro County, New Mexico. Collected 4 July 1889.
USNM 119028. Least Chipmunk (Neotamias minimus). Adult female. Sacramento Mountains, Sacramento Mountains, Otaro County, New Mexico. Collected 6 September 1902.

Comparison with Neotamias rufus

From Best et al. (1994): "quadrivittatus and rufus are narrowly allopatric or parapatric in western Colorado and northern Arizona. Although their sympatric occurrence has not been demonstrated, the two approach one another in the Gunnison River Valley, Colorado (Patterson, 1984)."

Comparison with Neotamias umbrinus

From Best et al. (1994): "Compared with umbrinus, the jugal bone of quadrivittatus is broad in lateral aspect and flares dorsally (average width is 2.0 mm; range, 1.7-2.4). In umbrinus, the bone typically is narrower (average width is 1.5 mm; range, 1.2-1.8) and the entire zygomatic arch is lighter and more slender. The skull of quadrivittatus is relatively shorter and broader than that of umbrinus. The average ratio of zygomatic breadth to greatest length of skull in quadrivittatus is 0.547 (range, 0.535-0.569). In a sample of umbrinus, the average ratio is 0.536 (range, 0.524-0.548). Absolute differences between these ratios are small, but cranial differences that the ratios reflect are visible to the unaided eye. [Neotamias] quadrivittatus has a less elongate brain case than umbrinus (Armstrong, 1972). The basic color of quadrivittatus is orange and it is brown in umbrinus. Coloration is especially different on the sides and shoulders. On the anterior part of the forehead quadrivittatus is orange to buffy while umbrinus is pale gray in Arizona (Hoffmeister, 1986), but in Colorado the forehead of quadrivittatus is gray and that of umbrinus is brown (B. J. Bergstrom, in litt.)."

References

Armstrong DM. 1972. Distribution of mammals in Colorado. Monograph of the Museum of Natural History, The University of Kansas, 3:1-415.

Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.

Best TL, Burt SL, Bartig JL. 1994. Tamias quadrivittatus. Mammalian Species (466):1-7. https://doi.org/10.2307/0.466.1

Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.

Howell AH. 1929. Revision of the American chipmunks (genera Tamias and Eutamias). North American Fauna 52:1-157.

Patterson BD. 1984. Geographic variation and taxonomy of Colorado and Hopi chipmunks (genus Eutamias). Journal of Mammalogy 65:442-456.