Least chipmunk (Tamias minimus)

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Least chipmunk fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Least chipmunk description

A small rodent with a long, narrow but fairly bushy tail ^{(2) (3)}, the least chipmunk (Tamias minimus) is the smallest and most widely distributed chipmunk species in North America ^{(2) (4) (5) (6)}.

The upperparts of the least chipmunk are marked with five conspicuous dark brown stripes, which run from the neck to the base of the tail. These are separated by four whitish stripes, the innermost of which have a more greyish to brownish tinge. The sides of the least chipmunk’s body are usually orange-brown to yellowish or greyish, and the underparts are white ^{(2) (3) (4) (7)}.

The head of the least chipmunk is also boldly striped ^{(2) (3)}, with two light and two dark stripes running from the nose to the ear, the uppermost stripe passing through the eye ⁽²⁾. The top of the head is a mixture of greys or browns ⁽²⁾. The tail is dull orange or yellowish below and edged with cream, while the feet are a pale yellowish-grey ⁽³⁾.

The least chipmunk has soft, dense fur which is moulted twice a year, the summer coat being brighter in colour than the more greyish winter coat ⁽⁴⁾. Like other chipmunks, this species has relatively short ears which are covered in short hairs ^{(2) (3)}, and pouches inside the cheeks which are used to carry food ⁽²⁾. The female least chipmunk may be slightly larger than the male ⁽⁶⁾.

Up to 21 subspecies of the least chipmunk have been described ⁽²⁾. These differ mainly in their colouration, varying from pale to much darker, and from greyer forms to those with deep orange on the sides. The intensity of the stripes may also vary ⁽³⁾. The least chipmunk can generally be distinguished from other chipmunk species by its small size, relatively long tail, and by having stripes which extend all the way to the base of the tail ^{(3) (5) (7)}. This species also characteristically runs with its tail held vertically rather than extended straight back ^{(3) (5)}.

Like other chipmunks, the least chipmunk gives a range of vocalisations, including a rapidly repeated, high-pitched ‘chip-chip-chip’ in alarm, as well as low ‘clucks’, trills and chatters ^{(2) (3) (4)}.

Also known as

New Mexico least chipmunk, Peñasco least chipmunk, Selkirk least chipmunk.

Synonyms

Neotamias minimus.

Size

Total length: 15.7 - 25 cm ⁽²⁾

Tail length: 5.1 - 11.4 cm ⁽²⁾

Weight

25 - 65.8 g ^{(2) (3)}

Least chipmunk biology

The diet of the least chipmunk consists mainly of seeds, nuts and fruits, although it will also take other plant material, such as leaves and flowers, as well as fungi, insects and occasionally birds’ eggs ^{(2) (3) (5) (6) (7)}. The least chipmunk may also sometimes feed on carrion ^{(3) (6)}.

While foraging, the least chipmunk will often fill its cheek pouches with seeds and nuts, which it then hoards in various locations or carries to its burrow to store for the winter ^{(2) (4) (7)}. This behaviour, typical of chipmunks, is reflected in the scientific name of the genus Tamias, which comes from the Greek for ‘storer’ or ‘distributor’ ⁽²⁾.

The least chipmunk is active throughout the day, sheltering in its burrow at night ^{(2) (5) (6) (7)}. Although mainly terrestrial, this species will sometimes climb trees and bushes ^{(2) (3) (4) (5) (7)} and has also been known to nest above ground ^{(1) (2) (5)}.

Generally, the least chipmunk builds a winter nest inside a burrow up to one metre below the ground ^{(1) (4) (7)}. Soil is removed through a “work hole”, which is later plugged and a new entrance opened so that the pile of excavated soil does not give away the burrow’s location ^{(2) (7)}. A chamber inside the burrow is filled with dry grass, shredded bark, fur, feathers and other soft materials, and also contains a cache of stored food ^{(2) (7)}. In the summer, the least chipmunk may abandon the burrow and instead build a nest in a hollow log, stump, rock pile or tree cavity ^{(1) (2) (4) (7)}. This species is territorial, defending its nest site against intruders ⁽⁷⁾,

The least chipmunk hibernates in its underground burrow from about September to April, with the exact timing depending on the location and the amount of snow cover ^{(1) (2) (3) (4) (7)}. Unlike many hibernators, the least chipmunk does not accumulate large fat reserves in autumn. It must therefore wake occasionally during the winter to eat its stored food ^{(2) (3) (4) (6) (7)}.

Breeding in the least chipmunk takes place in early spring, soon after individuals emerge from hibernation ^{(1) (3)}. Most mating takes place in April and May ^{(2) (3) (4)}, with the young typically being born in late May and early June ^{(3) (5) (7)}. The female least chipmunk usually gives birth to a single litter of between 2 and 8 young each year ^{(1) (2) (3) (4)}, after a gestation period of about 28 to 30 days ^{(2) (5)}. The young are hairless and blind at birth ^{(2) (7)}, and are suckled for up to 60 days ^{(4) (7)}. Although the female least chipmunk usually gives birth in the underground burrow, it has been suggested that the young may be moved to a tree nest several weeks later ^{(4) (7)}.

Young least chipmunks reach sexual maturity within their first year, breeding for the first time in the spring following their birth ^{(1) (4) (7)}. This species has been recorded living for up to six years ^{(2) (3)}, although it is vulnerable to a number of predators, including snakes, hawks, weasels, foxes, and domestic dogs and cats ⁽⁷⁾.

Least chipmunk range

The least chipmunk is widely distributed across Canada and the western United States, from Yukon and British Columbia to Quebec in Canada, and south to New Mexico, Arizona and California in the U.S. The eastern parts of its range in the U.S. include Wisconsin, Michigan and Minnesota ^{(1) (2) (3) (4)}.

Least chipmunk habitat

Although it may be found in a variety of habitats, the least chipmunk usually prefers coniferous and boreal forest ^{(1) (3) (5) (7)}, up to elevations of around 3,500 metres or more ^{(2) (3)}. It can also be found in deciduous forest, areas of sagebrush (Artemisia), dry scrub, sand dunes and sometimes alpine tundra ^{(1) (2) (3) (6) (8)}.

The least chipmunk is generally found in more open areas than other chipmunks ⁽³⁾. It tends to avoid closed forest interiors, instead preferring more open forest edges, clearings and disturbed areas ^{(5) (7)}.

Least chipmunk status

The least chipmunk is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Least chipmunk threats

The least chipmunk is a common and widespread small mammal and is not currently facing any major threats ⁽¹⁾. In some areas, chipmunks can occasionally do damage to crops, fruit trees or stored food ^{(4) (5)}, although they are also likely to be beneficial to humans by feeding on insect pests ⁽⁵⁾. In campgrounds and parks, least chipmunks can often become quite tame and even take food from humans ⁽²⁾.

Although the species as a whole is not under threat, two subspecies of the least chipmunk are considered to be of greater conservation concern ^{(4) (8) (9)}. The New Mexico or Peñasco least chipmunk, Tamias minimus atristriatus, was thought to be restricted to the Sacramento Mountains of south-central New Mexico, but is now believed to be extinct there. A second population was later discovered on the nearby Sierra Blanca ^{(4) (9)}, but only a few individuals may remain ⁽⁸⁾. The greatest threats to this subspecies have included the loss of mature ponderosa pine (Pinus ponderosa) forest, as well as habitat degradation through fire suppression, livestock grazing and the effects of climate change ⁽⁹⁾.

A second subspecies, the Selkirk least chipmunk (Tamias minimus selkirki), is known only from a single location in British Columbia and is considered to be vulnerable due to its restricted distribution ^{(4) (8)}. However, no immediate threats to this population are known, and it occurs near to a protected area. The validity of this population as a distinct subspecies has also yet to be confirmed ⁽⁸⁾.

Least chipmunk conservation

There are not known to be any specific conservation measures currently in place for the least chipmunk, and its large range includes many protected areas ⁽¹⁾.

Recommended conservation actions for the Peñasco least chipmunk (T. m. atristiatus) include protecting, maintaining and restoring critical habitat, retaining large logs and fallen trees within forests, and controlling livestock grazing. Population surveys and population monitoring should also be conducted at both the locations in which this subspecies has been known to occur ^{(8) (9)}.

A population census is also needed for the Selkirk least chipmunk (T. m. selkirki), and surveys are required to determine its exact distribution and abundance. Its status as a distinct subspecies also needs to be confirmed ⁽⁸⁾.

Find out more

Find out more about the least chipmunk and its conservation:

• Hafner, D.J., Yensen, E. and Kirkland Jr, G.L. (1998) North American Rodents: Status Survey and Conservation Action Plan. IUCN/SSC Rodent Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK. Available at:
  http://data.iucn.org/dbtw-wpd/edocs/1998-039.pdf
• Verts, B.J. and Carraway, L.N. (2001) Tamias minimus. Mammalian Species, 653: 1-10. Available at:
  http://www.science.smith.edu/msi/pdf/653_Tamias_minimus.pdf
• Smithsonian National Museum of Natural History: North American Mammals - Least chipmunk, Tamias minimus:
  http://www.mnh.si.edu/mna/image_info.cfm?species_id=207

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Glossary

Boreal forest

The sub-Arctic forest of the high northern latitudes that surrounds the North Pole and is mainly composed of coniferous trees.

Carrion

The flesh of a dead animal.

Deciduous forest

Forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Gestation

The state of being pregnant; the period from conception to birth.

Hibernate

Hibernation is a winter survival strategy in which an animal’s metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer.

Hibernation

A winter survival strategy in which an animal’s metabolic rate slows down and a state of deep sleep is attained. While hibernating, animals survive on stored reserves of fat that they have accumulated in summer.

Moult

Periodic shedding of (usually) the outermost body covering (such as feathers, fur or skin) during growth and development, or at specific times of the year.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Territorial

Describes an animal, a pair of animals or a colony that occupies and defends an area.

Tundra

Treeless, grassy plains characteristic of arctic and sub-arctic regions. They are very cold and have little rainfall.

References

1. IUCN Red List (March, 2012)
   http://www.iucnredlist.org/
2. Verts, B.J. and Carraway, L.N. (2001) Tamias minimus. Mammalian Species, 653: 1-10. Available at:
   http://www.science.smith.edu/msi/pdf/653_Tamias_minimus.pdf
3. Reid, F.A. (2006) A Field Guide to Mammals of North America. Houghton Mifflin Company, New York.
4. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
5. Hazard, E.B. (1982) The Mammals of Minnesota. University of Minnesota Press, Minneapolis.
6. Smithsonian National Museum of Natural History: North American Mammals - Least chipmunk, Tamias minimus (March, 2012)
   http://www.mnh.si.edu/mna/image_info.cfm?species_id=207
7. Kurta, A. (1995) Mammals of the Great Lakes Region. University of Michigan Press, Ann Arbor, Michigan.
8. Hafner, D.J., Yensen, E. and Kirkland Jr, G.L. (1998) North American Rodents: Status Survey and Conservation Action Plan. IUCN/SSC Rodent Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK. Available at:
   http://data.iucn.org/dbtw-wpd/edocs/1998-039.pdf
9. Frey, J.K. and Boykin, K. (2007) Status Assessment of the Peñasco Least Chipmunk (Tamias minimus atristriatus): Final Report. Conservation Services Division, New Mexico Department of Game and Fish, Santa Fe. Available at:
   http://freybiologicalresearch.com/Wildlife%20Inventories/Documents/Least_Chipmunk_Final%20Report.pdf