Family: Sciuridae, Squirrels view all from this family

Description The smallest tree squirrel in its range. Rust-red to grayish red above, brightest on sides; white or grayish white below. In winter, black line separates reddish back from whitish belly. Tail similar to back color, but outlined with broad black band edged with white. In summer, coat is duller. In winter, has prominent ear tufts. L 10 5/8–15 1/4" (270–385 mm); T 3 5/8–6 1/4" (92–158 mm); HF 1 3/8"–2 1/4" (35–57 mm); Wt 5–8 7/8 oz (140–252 g).

Endangered Status The Mount Graham Red Squirrel, a subspecies of the Red Squirrel, is on the U.S. Endangered Species List. It is classified as endangered in Arizona, where it lives only in high-elevation spruce and fir forests in the Pinaleno (Graham) Mountains. This squirrel has declined over a century's time because of the encroachment of human activities into its environment, mainly in the form of logging and recreational development. It is also possible that the introduction of Abert's Squirrels into the region has had an affect, as the two squirrel types would have to compete for the same resources.

Similar Species Douglas’ Squirrel usually duller red, has grayish to orangish underparts.

Breeding Litter of 3–7 young born March–April; sometimes a second litter August–September. Gestation 35 days. Newborns weigh about 1/4 oz (7 g), and are 2I0 (70 mm) long.

Habitat Often abundant in any kind of forest: natural coniferous forests, pine plantations, mixed, or hardwood forests; often around buildings.

Range Throughout much of Alaska and Canada; in U.S., south through Rocky Mountain states; in East, south to Iowa, n Illinois, n Indiana, n Ohio, n Virginia, and through Alleghenies.

Discussion The Red Squirrel is active all year, although it may remain inactive for a few days in inclement weather. In conifer forests, this squirrel feeds heavily on pine seeds, leaving piles of cone remnants everywhere. In the fall, it cuts green pinecones and buries them in damp earth. Like other North American tree squirrels, this species stores food in one or more large caches (sometimes up to a bushel’s worth in each) in the ground, in a hollow tree, or at the base of a tree. The Red Squirrel is a prodigious and opportunistic feeder, moving through its home range and trying many different items; in this way it keeps abreast of where and when various foods become available. Among the additional foods it may eat or store are acorns, beechnuts, and other nuts; seeds of hickory, tulip, sycamore, maple, and elm; berries; birds’ eggs and young birds; and fungi, including even the deadly (to humans) amanita mushrooms, which are often cached in trees. Red Squirrels also harvest maple sugar by biting into the trees’ xylem, letting the sap ooze out, and returning when the water in the sap (which when fresh is only 2 percent sugar) has evaporated and the sugar content is about 55 percent. Red maples apparently suffice for this where sugar maples are absent. The Red Squirrel’s nest, often constructed of shredded bark from a grapevine, is made in a hollow or fallen tree, a hole in the ground, a hummock, or a tree crotch (as are the leaf nests of gray squirrels). The female is in heat for only one day in late winter, at which time she will allow males on her territory. Animated nuptial chases precede mating. The Red Squirrel’s vocalizations include a slightly descending, drawn-out, rather nonmusical trill that can be heard for some distance, and a chatter of various notes and chucks.