Family: Sciuridae, Squirrels view all from this family
Description Brightly colored, from tawny to pinkish cinnamon, with 5 distinct longitudinal dark stripes, usually black, that are evenly spaced and about equal in width. Central 3 dark stripes extend to rump; lateral 2 only to mid-body. Pale stripes are white or grayish. Distinct black lower eye stripe. Sides of body and underside of tail grayish yellow. Top of head brown. Ears blackish in front, whitish behind. L 7 1/8–9 5/8" (181–245 mm); T 2 7/8–4 1/4" (73–108 mm); HF 1 1/8–1 3/8" (29–35 mm); Wt 1–2 1/2 oz (30–73 g).
Similar Species Least Chipmunk is smaller and paler, with underside of tail grayish yellow. Alpine Chipmunk is smaller, with shorter tail and less-contrasting stripes. Uinta Chipmunk is larger and less reddish, with dark brown side stripes and grayer head and shoulders. Panamint Chipmunk has tawny ears; top of head is brown. Lodgepole Chipmunk has larger ears and more-contrasting dark back stripes, with the outer wider and the inner narrower.
Breeding Mates April or May; 1 litter per year of 4–7 young born May–early June in a nest of leaves, grass, or lichens.
Habitat Brush-covered areas in coniferous forests, particularly yellow pine. Has a much broader range of habitats than do Allen’s, Lodgepole, and Long-eared chipmunks, with which it is often found.
Range Much of British Columbia and extreme w Alberta south to n California; east to w Montana and nw Wyoming.
Discussion In open forests where the sun casts sharp shadows, the well-defined stripes of the Yellow-pine Chipmunk afford protective coloration. Individuals of this species that were observed in Washington State remained active about seven months and hibernated about five, waking to eat about every two weeks and emerging in April and May. One study indicated that 97 percent of the individuals survived—a phenomenal rate of winter survival for a small mammal. Some individuals are active even on snow. This chipmunk lives in underground burrows, usually about 1 1/2 to 3 feet (450–900 mm) long and 7 to 21 inches (180–540 mm) deep in an open area within the forest; there is generally one entrance, though there may also be short side openings. Seeds, its most important food, are eaten as they are available—early in the season when green and later when ripe. When pinecones open in the fall, this chipmunk climbs trees to get the seeds. It also eats some insects and fungi. In Washington it apparently finds the thorns of the thistle no deterrent: First it eats the seeds from the head; then it cuts the head, which falls to the ground, and consumes it with impunity. In the fall the animal stuffs its cheek pouches with food to be stored in its burrows; one food cache contained an estimated 67,970 items, including 15 kinds of seeds, corn, and part of a bumblebee. It has at least 10 different calls; one sounds like a robin’s chirp and another, among the most common, is a sharp, accented kwist.
