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Species in this Guide: 206
Mammals of California
Created by: Robert Hole, Jr.
Least Chipmunk  Tamias minimus         View on EOL
Overview

Taxon Biology
The least chipmunk is the smallest and most widely distributed North American chipmunk. It occurs in a variety of habitats, from coniferous forests to meadows to sagebrush desert, feeding primarily on seeds but also eating flowers, buds, leaves, grasses, fungi, and even insects, eggs, and carrion. Least chipmunks are diurnal, like all ground-dwelling members of squirrel family. They retreat to their burrows at night and spend the winter underground, periodically waking up to feed on stored food. They scatter-hoard, storing seeds all over the place, so they unwittingly help many species of plants sprout in new places.

Links:
Mammal Species of the World
Project: Smithsonian Institution - North American Mammals  Source: Smithsonian Institution   CC License: by

Distribution
This species has a wide distribution in North America, from western Quebec to the Yukon in Canada, and southward to New Mexico, Arizona, and California in the United States. It is, however, absent from the Great Plains.Author: Linzey, A.V. & Hammerson, G., Compiler: Linzey, A.V. & NatureServe (Hammerson, G.)  Source: International Union for Conservation of Nature and Natural Resources   CC License: by-nc-sa

Conservation

Conservation Status
The New Mexico Least Chipmunk, Tamias minimus atristratus, is Critically Endangered; the Selkirk least chipmunk, Tamias minimus selkirki, is Vulnerable.Project: Smithsonian Institution - North American Mammals  Source: Smithsonian Institution   CC License: by

Management
Conservation Actions
This species is not of conservation concern and its range includes many protected areas.
Author: Linzey, A.V. & Hammerson, G., Compiler: Linzey, A.V. & NatureServe (Hammerson, G.)  Source: International Union for Conservation of Nature and Natural Resources   CC License: by-nc-sa

Threats
Major Threats
There are no major threats to this species.
Author: Linzey, A.V. & Hammerson, G., Compiler: Linzey, A.V. & NatureServe (Hammerson, G.)  Source: International Union for Conservation of Nature and Natural Resources   CC License: by-nc-sa

Trends
Population
This species is widespread and common. Highly favourable habitats may contain 30 or more per acre, though average densities typically range from 5 to 15 per acre (Jackson 1961).

Population Trend
Stable
Author: Linzey, A.V. & Hammerson, G., Compiler: Linzey, A.V. & NatureServe (Hammerson, G.)  Source: International Union for Conservation of Nature and Natural Resources   CC License: by-nc-sa

Physical Description

Morphology

Least chipmunks are the smallest of all chipmunks. Body length ranges from 185 to 222 mm (Burt, 1946). Individuals weigh between 42 and 53 g. Females are larger than males in some populations (Berstrom, 1999) There are three dark and two light stripes on the face and five dark and four light stripes along their sides. The middle stripe runs to the end of the tail (Burt, 1946). Dorsal background fur is orangish-brown, and ventral coloration is grayish-white (Kurta, 1995). The tail is bushy and long, ranging from 81 to 95 mm, and is pale brown in color (Hamilton and Whitaker, 1979). (Bergstom, 1999; Burt, 1946; Hamilton and Whitaker, 1979; Kurta, 1995)

Because they hibernate, these chipmunks are heterothermic. However, their body temperature remains relatively constant over short spans of time. There is a lower body temperature when the animal is torpid than when it is active. (Bergstom, 1999)

Other Physical Features: Endothermic; Heterothermic; Homoiothermic; Bilateral symmetry

Sexual Dimorphism: Female larger

>pEditor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Size
Sexual Dimorphism: Females are slightly larger than males.

Length:
Average: 201 mm
Range: 185-216 mm

Weight:
Average: 43.6 g
Range: 32-50 gProject: Smithsonian Institution - North American Mammals  Source: Smithsonian Institution   CC License: by

Ecology

Associations

Major threats to these animals include Mustela, goshawks, Cooper's hawks, snakes, Mustela vision, Vulpes vulpes, Lynx rufus, and Martes, as well as domestic dogs and cats. (Baker, 1983; Bergstom, 1999)
Editor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

General Ecology

Highly favorable habitats may contain 30 or more per acre, though average densities typically range from 5 to 15 per acre (Jackson 1961). Home range varies from less than an acre to 4 acres (Banfield 1974).
Author: Hammerson, G.  Source: NatureServe   CC License: by-nc

Habitat
Habitat and Ecology
It is found in various habitats. It is common in coniferous forests but also uses clearcuts, deciduous woods, sagebrush, riparian zones, and in western regions may even occur in alpine tundra. Winter nest is up to one metre below ground surface. Summer dens typically are in hollow logs or stumps, in rock piles, or under debris, evacuated burrows. Also nests in tree cavities above ground.

Breeds in early spring. Gestation lasts 31 days. Litter size is 2-7 (average 5-6). Only one litter per year. Second litter may be produced if first fails. Sexually mature in first spring. Home range varies from less than an acre to four acres (Banfield 1974). Feeds mostly on seeds, nuts, fruits, and acorns. May be active throughout the day, but prefers the sunny midday hours. Begins semi hibernation in late October. Fully active by mid-March. May be active on warm winter days.

Systems
  • Terrestrial
Author: Linzey, A.V. & Hammerson, G., Compiler: Linzey, A.V. & NatureServe (Hammerson, G.)  Source: International Union for Conservation of Nature and Natural Resources   CC License: by-nc-sa

Migration

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.
Author: Hammerson, G.  Source: NatureServe   CC License: by-nc

Trophic Strategy

Least chipmunks eat a wide variety of foods. Their diet including nuts, berries, fruits, grasses, fungi, snails, insects, and possibly some small birds and mammals. From April through October, much of a chipmunk's time is spent foraging. Least chipmunks forage both on the ground and in trees at heights up to 9 m (Kurta, 1995). Cheek pouches allow individuals to carry multiple food items back to their burrows, where they are either eaten or stored for future use. (Baker, 1983; Bergstom, 1999; Kurta, 1995)

Animal Foods: Birds; Mammals; Carrion; Insects; Terrestrial Non-insect Arthropods; Mollusks; Terrestrial Worms

Plant Foods: Leaves; Roots and tubers; Seeds, grains, and nuts; Fruit; Flowers

Other Foods: Fungus

Foraging Behavior: Stores or caches food
Editor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Life History and Behavior

Behavior

Least chipmunks are adept climbers. Some individuals construct nests high above the ground. Chipmunks climb trees in order to warm themselves in the sun during periods of cool weather (Hamilton and Whitaker, 1979).

Least chipmunks are most active between April and October. Nests are built seasonally, with summer homes being constructed from leaves and bark in rotting logs and tree cavities. Winter nests are located in underground burrows that consist of dried grass, bark, fur, feathers and soft vegetation (Kurta, 1995). With the onset of cold weather, chipmunks retire to these burrows, where they enter torpor and live off stored food until spring (Kurta, 1995). Hibernation in these animals is not as deep as it is in ground squirrels, and they awake frequently to snack on stored food during the winter months (Bergstom, 1999). Least chipmunks are territorial and will defend their nests from invaders.

Least chipmunks are diurnal. In general, they are not social, except for mating and rearing young. However, when provisioned by humans, they are remarkably tollerant of conspecifics (Bergstrom, 1999). (Baker, 1983; Bergstom, 1999; Hamilton and Whitaker, 1979; Kurta, 1995)

Home Range

Home ranges have been estimated at 1/4 of an acre. Some areas have up to 6 individuals per acre. (Banfield, 1974)

Key Behaviors: arboreal; terricolous; diurnal; motile; sedentary; hibernation; solitary
Editor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Cyclicity

Comments: May be active throughout the day, but prefers the sunny midday hours. Begins semihibernation in late October. Fully active by mid-March. May be active on warm winter days.
Author: Hammerson, G.  Source: NatureServe   CC License: by-nc

Life Expectancy
Maximum longevity: 10 years (captivity) Observations: One wild born specimen was about 10 years of age when it died in captivity (Richard Weigl 2005).Editor: de Magalhaes, J. P.  Source: Joao Pedro de Magalhaes   CC License: by

Reproduction

The mating system of these animals has not been well described. Males emerge from hibernation earlier than females, and apparently engage in some level of competition for mates. It is likely, therefore, that the species is either polygynous or polygynandrous. (Baker, 1983)

Individuals become sexually mature at 10 months of age (Kurta, 1995). Most mating occurs in April when females first emerge from hibernation. Gestation lasts approximately 30 days (Hamilton and Whitaker, 1979). Litter size varies from 2 to 6 young. There is normally a single litter during the breeding season, although females may produce a second litter if their first litter is lost (Burt, 1946). Newborns are naked and pink in color, measuring 50 mm in length and weighing an average of 2.25 g (Banfield, 1974). Eyes open at 28 days and fur is fully grown in by 40 days (Baker, 1983). Lactation lasts approximately 60 days and offspring remain with the mother for six weeks or longer (Kurta, 1995). (Baker, 1983; Banfield, 1974; Burt, 1946; Hamilton and Whitaker, 1979; Kurta, 1995)

Key Reproductive Features: Iteroparous; Seasonal breeding; Gonochoric/gonochoristic/dioecious (sexes separate); Sexual; Fertilization; Viviparous

These chipmunks usually breed once per year.>p

Breeding occurs in early April when these chipmunks awake from hibernation.>p

Parental care in least chipmunks is extensive. Young are altricial, and are not even fully furred until they reach about 40 days of age.

Females chose nursery nests while they are pregnant. These nests are located in stumps, under logs, in brush piles, or rock piles. They are generally connected to chambers filled with cached food supplies. A female positions her nursery nest so that it is protected from rainfall and runoff, to ensure the comfort and health of her offspring when they arrive. Nests are often lines with grass.

Mothers take care of their young until they are weaned, sometime after 60 days of age. They provide food, shelter, grooming, and other care for the pups.

The role of males in the care of offspring is not certain. There are some indications that males may help to defend the home range of female's whose young they have sired. They may even help to maintain the nursery nest, and bring food to the young. (Baker, 1983; Bergstom, 1999; Burt, 1946)

Parental Investment: Altricial; Pre-fertilization; Pre-fertilization :: Provisioning; Pre-fertilization :: Protecting; Pre-fertilization :: Protecting :: Female; Pre-hatching/birth; Pre-hatching/birth :: Provisioning; Pre-hatching/birth :: Provisioning :: Female; Pre-hatching/birth :: Protecting; Pre-hatching/birth :: Protecting :: Male; Pre-hatching/birth :: Protecting :: Female; Pre-weaning/fledging; Pre-weaning/fledging :: Provisioning; Pre-weaning/fledging :: Provisioning :: Female; Pre-weaning/fledging :: Protecting; Pre-weaning/fledging :: Protecting :: Male; Pre-weaning/fledging :: Protecting :: Female; Pre-independence; Pre-independence :: Provisioning; Pre-independence :: Provisioning :: Male; Pre-independence :: Provisioning :: Female; Pre-independence :: Protecting; Pre-independence :: Protecting :: Male; Pre-independence :: Protecting :: Female
Editor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Molecular Biology and Genetics

Molecular Biology
Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 2
Species With Barcodes: 1

Compiler: Sujeevan Ratnasingham, Compiler: Paul D.N. Hebert  Source: Barcode of Life Data Systems   CC License: by

Relevance to Humans and Ecosystems

Benefits

Least chipmunks are predators of pest insects and may play a role in seed or pollen dispersal.
Editor: Phil Myers, Museum of Zoology, University of Michigan, Editor: Nancy Shefferly, Animal Diversity Web Staff, Author: Kurt Schlimme, University of Michigan  Source: The Regents of the University of Michigan and its licensors   CC License: by-nc-sa

Show/Hide iNaturalist Observations Map for this species. Source: iNaturalist