No disease has been recorded for this subspecies but a related form in California (Citellus b. beecheyi) is known to harbor plague ([Kellogg], 1935: 857) and tularemia ([McCoy], 1911: 53-71).
Citellus lateralis (Say)
Golden-mantled ground squirrel
Description.—The head and body measure about 6 inches and the tail about 4 inches. The head is large and rounded with eyes and ears of moderate size. The body is stouter than that of a chipmunk. The tail is long and well furred. Upper parts are buffy gray with one pale stripe bordered by two black stripes extending from shoulders to rump, and the underparts are buffy. The head and shoulders are tawny. The tail is buffy beneath and darker above.
Externally golden-mantled ground squirrels somewhat resemble chipmunks but actually are no more closely related to chipmunks than are other ground squirrels. They are larger than chipmunks and their stripes differ in that there is but one pale stripe on each side bordered with black stripes rather than two pale stripes, and in that the stripes end at the shoulders rather than continuing on to the face.
These ground squirrels are distributed in mountainous areas of western North America from central British Columbia south to central Arizona and New Mexico. A closely related species (Citellus madrensis) occupies a limited area in northern Mexico and another lives in the Cascades of Washington. There are two subspecies of lateralis in Washington, each with a major part of its range outside of Washington.
This species inhabits mountain clearings, parks and talus slides, where it is most common about rocks, stumps, and logs. Its fondness for talus slides and outcrops has earned it the common name of "rock squirrel" in some places.
Entrances to burrows are usually beside a rock, stump, or root, or are concealed under talus slides. A burrow excavated by [Hatt] (1927) in Colorado was three inches in diameter at the entrance and uniformly two inches in diameter for the rest of its length. Most of the burrow was 8 inches beneath the surface. The tunnel branched twice and contained one pocket, probably a turning or passing chamber, in addition to the nest. "A runway surrounded the nest on three sides, from which there were four passages leading in. The nest cavity was 4 inches deep, the nest not filling the space available, but occurring more as a mat in the bottom of a cup."
The habits of this ground squirrel in Washington are little known. Since it occupies areas that are cold and under deep snow in winter, it probably hibernates. According to [Howell] (1938: 32) these animals become fat in the fall and must retire for the winter about the middle of September.
The food habits of these ground squirrels in Washington are little known. In the Pend Oreille Mountains, Pend Oreille County, I found them eating the fruit of the western raspberry (Rubus leucodermis). [Howell] lists, as food of this species, the seeds of yellow pine and douglas fir, serviceberries, other berries and seeds, grain, mushrooms, and several kinds of insects.