Family: Sciuridae, Squirrels view all from this family

Description A medium-size chipmunk, basically orange overall. Head cinnamon, shading to gray. Creamy white below; tawny wash on sides. 3 median stripes on back black, with yellowish-orange margins; outer stripes brownish. Shoulders gray. Rump and thighs cinnamon-buff. Tail black-tipped, white-bordered, tawny below. Ears blackish in front, whitish behind. L 8 1/8–9 3/8" (207–240 mm); T 3 3/8–4 1/8" (85–105 mm); HF 1 1/4–1 3/8" (31–34 mm); Wt about 2 oz (60 g).

Similar Species Very similar Uinta Chipmunk is basically brown. Hopi Chipmunk is usually paler and redder, with back stripes less black. Gray-collared Chipmunk has gray shoulders. Gray-footed Chipmunk has gray on upper part of hindfoot.

Breeding Mates in spring; 1 litter of 2–6 young born in late spring. Young are nearly full grown by July–August. Presence of some small young in October may indicate an occasional second litter.

Habitat In Colorado, a variety of habitats including desert scrub, grassland-chaparral, tundra, and spruce-fir and pinyon-juniper forests. In New Mexico, primarily ponderosa pine areas, but not restricted to forested habitats.

Range Southeastern Utah, Colorado, ne Arizona, and n New Mexico.

Discussion Active in early morning and late afternoon, the Colorado Chipmunk gives a short warning bark when alarmed. More arboreal than most chipmunks, it tends to occupy coniferous areas and has been seen eating seeds at the tops of spruce trees. It feeds on a great variety of seeds, fruits, fungi, and insects, and its caches often contain grain seeds. In Colorado this chipmunk is often associated with the more abundant Least Chipmunk, which occupies meadows. In New Mexico, it occurs at higher elevations—in ponderosa pine, Douglas fir, and aspen—than the Cliff Chipmunk, which occurs in lower-elevation pinyon-pine and juniper woods. This species occurs in male-female pairs during the breeding season.