Least chipmunk

Tamias minimus


Eutamias minimus (Bachman, 1839), Sweetwater County, Wyoming, United States. Twenty-two subspecies.


English: Western chipmunk, little chipmunk; French: Tamia mineur; German: Kleiner Chipmunk.

PHYSICAL CHARACTERISTICS Smallest squirrel. 7.2-9.4 in (18.3-23.9 cm); 1.3-1.8 oz (35.9-50.3 g). Varies in color seasonally and regionally. Yellowish gray to brownish gray. Three dark brown stripes on each cheek separated by two narrow white stripes running nose

to ear. Dorsally there are five black stripes edged in brown and separated by four narrower gray stripes.


Throughout the boreal forests of Canada from the western Yukon to east of the Ontario-Quebec border and south through the Rocky Mountains to Arizona and New Mexico.


Primarily associated with open coniferous forests and forest edges but occurs in a wide range of other habitats including deciduous forests, sagebrush, riparian areas, and alpine tundra. Winter nests are constructed below ground for protection from cold. Summer nests can be in hollow logs, stumps, tree cavities, rock piles, under debris, or in excavated burrows. Entrances of excavated burrows are preferentially constructed under a rock or other object for protection.


Active from late April or May to September. Gives a distinctive high pitched "chip-chip" call. While foraging among buried seed caches, these chipmunks will often urinate on the patch before leaving. A study at the University of Oklahoma by Lynn Devenport and others has shown that this behavior acts to deter the marker and other chipmunks from visiting that patch again. They believe that this increases foraging efficiency by advertising seed caches that are already depleted.


Forages primarily for seeds, nuts, berries, and acorns. Fruit and berries are harvested only for their seeds, the rest is discarded. Also will prey upon insects, bird's eggs, and chicks. Instead of storing fat like other hibernating rodents such as marmots, least chipmunks store seeds in their winter chamber. They interrupt torpor throughout the winter to feed from these seed caches.


Breeding occurs soon after emergence from hibernation. Gestation is 28-30 days. Litters with an average of 5 pups (maximum 7) arrive in mid-May. A second litter is attempted if the first one is lost.


Two subspecies are of special conservation concern because of their restricted distributions. T. m. astristriatus is classified as Critically Endangered and consists of a small population restricted to a single glacial cirque in New Mexico. T. m. selkirki classified as Vulnerable and is restricted to less than 40 mi2 (100 km2) within the Purcell Mountains in British Columbia, Canada.


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