334 Tamias quadrivittatusemerging rapidly to forage when weather permits. T. qua-
drivittatus begins breeding in spring (April or May), but it
may have a bimodal breeding season in the south, during
February and again during July. Litters of two to six young
are born in nests from May to June. One litter is generally
produced each year; however, the occurrence of pregnant
and lactating females in late summer in some areas suggests
that there is either a second litter or late breeding. Nests are
found in crevices, under rocks, and in underground bur-
rows. The young are weaned at 6–7 weeks and disperse by
the fall. Colorado chipmunks are primarily terrestrial but
frequently climb shrubs and trees in search of food. T. qua-
drivittatus is a generalist herbivore, eating the seeds and
fruits of forbs, grasses, shrubs, and trees; however, this chip-
munk is opportunistic and will frequently consume insects
and other animal matter. As is the case for many other chip-
munks, seeds are the principal component of Colorado
chipmunk diets. Seeds are gathered in cheek pouches and
placed in crevices or under rocks, or transported to an un-
derground location near the nest chamber, for storage and
use over the winter. Individual home ranges average 2.7–
2.8 ha. This species’ overwinter survival rate is less than
33 percent, with local extirpation common. Due to the mod-
est size of Colorado chipmunks, they are preyed on by a
variety of raptors, mustelids, felids, canids, and snakes. T.
quadrivittatus runs for the protective cover of rocks or logs,
or else it climbs trees when under threat. “Chips” and trills
are loud high-pitched calls often given from a safe vantage
point when the animal is alarmed. Colorado chipmunks are
not trapped or hunted; occasionally they are a nuisance
near homes or in picnic areas.
general references: Bergstrom and Hoff mann 1991;
Best 1994; Rivieccio et al. 2003; R. M. Sullivan 1996.Tamias rufi caudus (A. H. Howell, 1920)
Red-Tailed Chipmunkdescription: This species is a large chipmunk. It has an or-
angish dorsum, and fi ve black to brownish da rk dorsa l st ripes
interspersed with four gray to yellowish brown stripes. The
belly is white to cream colored, and the ventral surface of the
tail is reddish with black and pink borders. Where T. rufi cau-
dus is sympatric or parapatric with subspecies of T. amoenus
and T. minimus, it can be distinguished by its larger body and/
or larger skull and its distinctly reddish tail.size: Female—HB 127.2 mm; T 102.9 mm; Mass 63.2 g.
Male—HB 121.8 mm; T 98.3 mm; Mass 57.1 g.
Sex not stated—HB 125.3 mm; T 109.1 mm; Mass 67.3 g.distribution: This species’ range extends from southeast-
ern British Columbia and southwestern Alberta (Canada) to
northeastern Washington and east through Idaho to west-
ern Montana (USA).geographic variation: Two subspecies are recognized.T. r. rufi caudus—eastern half of the species’ range. This sub-
species has a longer baculum than T. r. simulans.Tamias quadrivittatus. Photo courtesy James N. Stuart.