Red underneath, dark on the sides
This is one of the bigger chipmunks, about 9 to 10 inches long including the tail. The stripes are the standard chipmunk pattern, but the colors set it apart: dark, grayish-brown sides and a tail that glows reddish on its underside, most obvious when the animal flicks it while running. The overall effect is darker and richer than the pale, sandy chipmunks of drier country.
Within its range, the least chipmunk is smaller and paler, and the yellow-pine chipmunk is brighter-sided. Where their ranges meet in northern Idaho and western Montana, the red-tailed’s size and dark flanks are the working marks, though chipmunk identification in this region genuinely rewards patience.
A chipmunk of deep woods
Most western chipmunks like open, sunny ground. This one takes the shade. It lives in mature and second-growth coniferous forest, cedar-hemlock bottoms, and avalanche chutes with heavy cover, from valley floors up toward treeline. It climbs well and often, feeding and even nesting above ground more than most of its relatives.
The diet runs to conifer seeds, huckleberries and other soft fruit, fungi, and insects, all hauled in cheek pouches to caches that carry the animal through winter. Like other chipmunks it sleeps through the cold months but wakes to eat from its stores, so winter isn’t a total disappearance. Reports still concentrate in the warm months, when the animals are out, vocal, and busy.
Quiet and holding steady
The IUCN rates the red-tailed chipmunk Least Concern. Its range crosses the border into British Columbia and Alberta, and the US portion, the northern Rockies and the Selkirks, still holds large blocks of the dense forest it prefers. Records run from the valleys of western Montana through the Idaho panhandle into northeastern Washington, matching the belt of wet inland forest.
Because it favors heavy cover, it is seen less often than the chipmunks of open campgrounds, and its record counts likely understate it next to its bolder relatives. It’s a reminder that in the northern forest, the chipmunk you hear rustling in the huckleberries is as likely this one as any other.
