The red-tailed chipmunk is found in the central Rocky Mountain region of the United States in northwestern Montana, northern Idaho and northeastern Washington. In Canada, the range of -Tamias ruficaudus- just touches extreme southwestern Alberta and the East Kootenay valley of southern British Columbia. (Banfield, 1974; Nowak, 1999)

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Northeastern Washington eastward through northern Idaho to western Montana, and adjacent southeastern British Columbia and southwestern Alberta; elevations of 720-2400 m (Hoffmann et al., in Wilson and Reeder 1993; Best 1993).

The red-tailed chipmunk is darker colored and larger than most chipmunks. The appearance of this chipmunk is generally similar to that of Tamias minimus (least chipmunk) and the yellow pine chipmunk. However, the red-tailed is larger and colored more brightly. In general, the pelage is rufous on the shoulders and sides, with this color fading out towards the hips. The back has a deep orange-brown tone and the rump is a shade of gray. The feet are a light brown color and the underparts are ivory. The color of the tail is rufous on the dorsal side with the ventral side a bright orange or brick red. The tail also has a black band and the tips of the hairs are yellowish. The ears are black. T. ruficaudus has five dark stripes that range from black to fuscous. The central dark stripe runs between the ears to the tail. The four pale stripes are grayish to white. The forehead is chocolate brown and the cheeks are characterized by two milky stripes separated by three brown stripes. The eye stripe is black and the stripe below the eye is brownish.

The winter pelage of T. ruficaudus is soft, dense and slightly wooly. There are two molts each year, one occurring in the spring and a second molt in the early autumn. The summer pelage differs from the winter in that it is more brightly colored.

The dental formula of the red-tailed chipmunk is 1/1 0/0 2/1 3/3=22. The skull has a short rostrum and is ovate. The postorbital processes are slender and long. The subgenus Neotamias, to which the red-tailed chipmunk belongs, is differentiated from the subgenus Tamias in that Neotamias has two premolars on each side of the upper jaw and Tamias only has one.

The red-tailed chipmunk is sexually dimorphic. Females are approximately 3% larger than males in head length and body. Males also have narrower skulls than females.

(Banfield, 1974; Best, 1993; Nowak, 1999; Smith, 1993)

Average mass: 60 g.

Average mass: 75 g.

Length: 25 cm

Weight: 60 grams

• Terrestrial

The red-tailed chipmunk inhabits dense coniferous forests. Its numbers are greatest where shrubby growth is rich. These conditions typically occur in forest openings or edges. They can be found in forests of -Tsuga heterophylla- (western hemlock), -Thuja plicata- (western red cedar), -Pseudotsuga menziesii- (Douglas fir), and -Picea englemanni- (Englemann spruce). They are limited by open -Pinus ponderosa- (Ponderosa pine) on the western edge of their range. -T. ruficaudus- occupies bunches of stunted pine and spruce trees, and -Rhododendron- (mountain rhododendron) and -Vaccinium- (blueberry bushes) on the margins of meadows. They occur in Washington in mixed second-growth forests of -Pinus contorta- (lodgepole pine), -Larix occidentalis- (western larch), Englemann spruce, Douglas fir, -Abies grandis- (grand fir), and -Populus tremuloides- (aspen).

In northern Idaho, the red-tailed chipmunk is considered to be the most widely distributed and common chipmunk. They are plentiful higher in the mountains. In the Ponderosa pine zone, they can be found in openings with great amounts of light where boulders and low brush are present. This usually occurs along older roadways and at the lower edge of foothills. -T. ruficaudus- can be found near fallen logs and brush piles in the Canadian zone.

This species of chipmunk typically resides in burrows and on the ground, but can climb trees and bushes at times. They look for protection in old logs, crevices among rocks, and their burrows. (Best, 1993; Nowak, 1999)

Terrestrial Biomes: forest

Comments: Various types of coniferous forest and woodland such as spruce-fir, cedar-hemlock, ponderosa pine, riparian communities, and pine/spruce/rhododendron/blueberry at margins of timberline meadows. Most abundant in forest openings or edges, where shrubby undergrowth is abundant. Where range overlaps with T. AMOENUS, seems to prefer dense cover (Larrison and Johnson 1981). Primarily terrestrial, also climbs trees. Often around logs, brush piles, or boulders in Idaho. See Best (1993) for further details for different locations. Nests are made in shrubs or trees (e.g., on limbs 6-18 m above ground, or in cavities), in crevices among boulders, under old log piles, or underground.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Red-tailed chipmunks gather dry food that they carry in their cheek pouches and store underground. They feed at discrete times during daylight hours. These animals become torpid in the winter and feed from time to time upon their larder. Their diet includes the seeds of fir trees, honeysuckles, locusts, and cranberries. In Idaho, they have also been observed feeding upon the seeds of Douglas knotweed. In Montana, the chipmunk eats the fruits and seeds of nine-bark, wild rose, Ponderosa pine, snow brush, serviceberry, big whortleberry, buckbrush, knotweed, grass, huckleberry, mountain maple, and bull thistle. They also eat the leaves and flowers of the dandelion, arnica, currant, balsam-root, glacier lilly, oyster plant, willow herb, and tarweed. -T. ruficaudus- has been caught in the wild with steel traps baited with meat. (Best, 1993; Nowak, 1999)

Comments: Feeds on seeds and fruit of various trees and shrubs, also leaves and flowers of various forbs; probably also fungi.

Home range evidently is not more than a few hundred meters across (see Best 1993).

Comments: Active mainly April-October; wakes periodically in winter to feed from food cache.

Average lifespan

Status: wild: 8.0 years.

Mating in -T. ruficaudus- can occur from late February to early July but usually takes place in April or May. Pregnancy rates vary among age groups. Females that were 10 to 16 months of age were pregnant less often than older females. The overall rate of pregnancy for the population was 68 to 83% where females 10 to 16 months of age were not considered. There is only one breeding season per year, unless a litter is lost. In this case the female can enter estrus again and bear a second litter. The gestation period is 28 to 36 days. Embryos of 25 mm in head-rump length are full term. The litter size is usually three to eight young and sexual maturity is reached within the first year of life. The record of longevity in the wild for chipmunks was achieved by -T.ruficaudus-. This particular animal lived for eight years. However, fewer than 10% of the individuals survive more than 64 months. (Best, 1993; Nowak, 1999)

Average gestation period: 31 days.

Average number of offspring: 5.5.

Average age at sexual or reproductive maturity (female)

Sex: female: 335 days.

Breeds late April-May, earliest at low elevations. Breeding may extend through August in north. Most adult females become pregnant each year. Gestation lasts about 1 month. In Montana, births occur from late May to mid-June at lower elevations, early to late June at higher elevations. Litter size usually 4-6. Young appear above ground at about 39-45 days (in July). Some live as long as 6-8 years in the wild. See Best (1993).

Generally, -Tamias ruficaudus- are abundant in most areas. They seem to have avoided the fate of some of their close relatives, -Tamias palmeri-, -Tamias minimus atristriatus-, and -Tamias quadrivittatus australis-, which have all appeared on the IUCN list or have become extinct. (Nowak, 1999)

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N3 - Vulnerable

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Red-tailed chipmunks typically favor brush-covered or rugged land. However, sometimes they occur near agricultural crops. When this happens, they can do damage by eating planted seed, young forest plantings, and even fruit trees. (Nowak, 1999)

The red-tailed chipmunk can be tamed quite easily for the purposes of laboratory study. (Best, 1993)

Comments: Bacular morphology suggests that subspecies simulans may be a distinct species (Patterson and Heaney 1987) but pelage coloration indicates considerable gene flow (Best 1993).

Formerly included in genus Eutamias, which recently was included in the genus Tamias (Levenson et al. 1985; Jones et al. 1992, Hoffmann et al., in Wilson and Reeder 1993). Based on patterns of variation in ectoparasites (Jameson 1999) and molecular phylogenetics (Piaggio and Spicer 2001), the North American mammal checklist by Baker et al. (2003) placed all North American chipmunks (except Tamias striatus) in the genus Neotamias. Thorington and Hoffmann (in Wilson and Reeder 2005) noted that chipmunks could be legitimately allocated to one (Tamias), two (Neotamias, Tamias), or three (Tamias, Neotamias, Eutamias) genera; they chose to adopt the single-genus (Tamias) arrangement.

See Sutton (1992) for a key to the species of Tamias.