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yellow-cheeked chipmunk

Tamias ochrogenys

What do they look like?

Yellow-cheeked chipmunks are the largest members of their group (subgenus Neotamias), which includes most Townsend’s chipmunks of western North America. They range in length from 233 to 297 mm. Their tails range from 97 to 130 mm in length. The markings on their fur have alternating bands of black (5 bands) and light tan (4 bands) running lengthwise along their back. They also have two other sets of bands of similar coloration above and below their eyes. As with other chipmunks of their group, they have a pale tan or yellowish underbelly. Their fur is different at different times of the time of year. They shed twice each year, once in the fall and again in the spring. Their winter coat is notably longer, softer, and denser. Although yellow-cheeked chipmunks are similar to other members of their group, they are distinguished by their genetics, vocalizations, and anatomy. They make sounds known as 'chip vocalizations', which consist of paired syllables, resulting in a “chip-chip” call. On average, female yellow-cheeked chipmunks are about five percent larger than males; this is known as sexual dimorphism. (Foley and Neito, 2011; Gannon and Lawlor, 1989; Gannon, et al., 1993; Roberson, 2009)

  • Sexual Dimorphism
  • female larger
  • Range mass
    78 to 117.5 g
    2.75 to 4.14 oz
  • Average mass
    94.1 g
    3.32 oz
  • Range length
    233 to 297 mm
    9.17 to 11.69 in

Where do they live?

Yellow-cheeked, or redwood chipmunks (Tamias ochrogenys), have a narrow distribution in California. Their home range is a small patch along the coast of the northern part of the state that extends no more than 40 kilometers from the shore. The range of this species begins in Sonoma County and extends north to the Eel River, in Humbolt County. Their entire range is less than 20,000 kilometers squared. (Gannon and Lawlor, 1989; Gannon, et al., 1993; Linzey and Hammerson, 2008)

What kind of habitat do they need?

Yellow-cheeked chipmunks make burrows for stashing food and avoiding predators. These burrows are huge and made in dense forest undergrowth and downed trees. These animals rely on coastal redwood forests and mixed coniferous or Douglas fir forests for their habitat, although they are rarely found in the tree canopy. (Foley and Neito, 2011; Rosenberg and Anthony, 1993)

  • Range elevation
    Sea level to 1280 m
    to 4199.48 ft

How do they reproduce?

In a year, females will have no more than one litter. No data were found specific to this species, but in other species of chipmunks, females were available for breeding for only one day at a time, when this occurs, they usually mate with multiple males. (Gashwiler, 1976; Roberson, 2009)

Males are in breeding condition during March, April, and May. Females are in breeding condition about a month after males, and maintain it for about two months longer. Litters range from two to five young, with an average litter size of four. (Gannon, et al., 1993; Gashwiler, 1976; Polite and Harvey, 2000)

  • How often does reproduction occur?
    Yellow-cheeked chipmunks breed once yearly.
  • Breeding season
    Yellow-cheeked chipmunks breed during mid-March and into the summer months.
  • Range number of offspring
    2 to 5
  • Average number of offspring

There was no data found for this specific species; however, the young of most chipmunks are altricial, meaning they are far from independent and require a lot of parental care. (Roberson, 2009)

How long do they live?

No reliable data exists specifically for this species. However, in one study, the oldest yellow-cheeked chipmunk was two years old. This is probably much lower than their actual lifespan. Eastern chipmunks, a close relative of yellow-cheeked chipmunks, live 3 to 4 years. (Foley and Neito, 2011; Levenson, et al., 1985)

How do they behave?

This species is diurnal and does not hibernate; however, they are slightly less active in winter months. Their burrows are usually made in downed trees, and thick underbrush; often just above ground or slightly below. The burrows mainly consist of large networks of many small tunnels. Nest cups have not been found in burrows, this suggests yellow-cheeked chipmunks only use their burrows occasionally. Chipmunks are considered solitary animals; they are rarely social outside of the breeding season. (Foley and Neito, 2011; Roberson, 2009)

  • Range territory size
    0.005 to 0.73 km^2

Home Range

Female yellow-cheeked chipmunks inhabit areas ranging from 0.005 to 0.24 kilometers squared and males inhabit areas ranging 0.006 to 0.73 kilometers squared. Males travel maximum distances of 0.1 to 1.26 kilometers, while females traveled 0.14 to 0.63 kilometers. Although chipmunks are not social, they are also not usually territorial, their home ranges often overlap. (Foley and Neito, 2011; Roberson, 2009)

How do they communicate with each other?

Yellow-cheeked chipmunks make low frequency calls, as compared to other chipmunks. These calls include two quick chirps that are repeated. These calls are unique enough to distinguish them from other species. Chipmunks also use visual cues to communicate with each other. (Gannon and Lawlor, 1989; Roberson, 2009)

What do they eat?

At the end of winter and beginning of spring, a large part of their diet is fungus. The rest of the year they eat a variety of foods. Based on the contents of their cheek pouches, yellow-cheeked chipmunks likely eat the following: western raspberry, buckthorn, blue-blossom, wax myrtle, California huckleberry, poison oak, bull thistle, scotch broom, and acorns. Yellow-cheeked chipmunks may also eat insects. (Gannon, et al., 1993)

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit
  • flowers
  • Other Foods
  • fungus

What eats them and how do they avoid being eaten?

Predators of yellow-cheeked chipmunks possibly include skunks, minks, weasels, martens, domestic cats, and numerous owl and hawk species. They use burrows and lower branches of trees to escape predation. Chipmunks use alarm calls to deter and confuse predators. These calls also warn other chipmunks in the area of possible danger. (Foley and Neito, 2011; Polite and Harvey, 2000; Roberson, 2009)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Since yellow-cheeked chipmunks live both on the ground and in trees, they may transfer diseases and parasites to woodrats and tree squirrels as they share habitats with both species. They are known hosts of western black-legged ticks (Ixodid pacificus). As with the diet of all chipmunks, their foraging behavior and a tendency to stash food in burrows makes them important seed dispersers, although some chipmunks destroy certain types of seeds. Chipmunks are also important in the spread of mycorrhizal fungi. (Foley and Neito, 2011; Gannon, et al., 1993; Roberson, 2009)

  • Ecosystem Impact
  • disperses seeds
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • western black-legged ticks (Ixodid pacificus) (class Arachnida; phylum Anthropoda)

Do they cause problems?

Chipmunks can become pests, they form dense populations and their nesting and feeding habits are very general. When living close to humans they can cause damage to gardens, homes, and campsites. Tamias ochrogenys are known hosts of western black-legged ticks (Ixodid pacificus). These ticks are known to transmit Anaplasma phagocytophilum, a bacterium that causes sickness in humans, domestic animals and wildlife. Chipmunks also carry various other tick transmitted diseases, including the Hantavirus. (Foley and Neito, 2011; Linzey and Hammerson, 2008; Roberson, 2009)

  • Ways that these animals might be a problem for humans
  • injures humans
    • carries human disease

How do they interact with us?

Chipmunks have immeasurable value to humans as dispersers of seeds and mycorrhizal fungi. (Gannon, et al., 1993; Roberson, 2009)

Are they endangered?

Yellow-cheeked chipmunks are common within their range and currently, no major threats have been identified. Population estimates for the species exceed 10,000 individuals and the population is reported to be stable. (Linzey and Hammerson, 2008)


Mark Fletcher (author), University of Alaska Fairbanks, Leila Siciliano Martina (editor), Animal Diversity Web Staff.


Foley, J., N. Neito. 2011. The ecology of tick-transmitted infections in the redwood chipmunk (Tamias ochrogenys). Ticks and Tick-borne Diseases, 2/2: 88-93.

Gannon, W., D. Kain, R. Forbes. 1993. Tamias ochrogenys. American Society of Mammalogists, 445: 1-4. Accessed October 02, 2012 at //

Gannon, W., T. Lawlor. 1989. Variation of the Chip Vocalization of Three Species of Townsend Chipmunks. Journal of Mammalogy, 70: 740-753.

Gashwiler, J. 1976. Biology of Townsend's chipmunks in Western Oregon. The Murrelet, 57, No. 2: 26-31.

Levenson, H., R. Hoffmann, C. Nadler, L. Deutsch, S. Freeman. 1985. Systematics of the Holarctic Chipmunks (Tamias). Journal of Mammalogy, 66/2: 219-242.

Linzey, A., G. Hammerson. 2008. "Tamias ochrogenys" (On-line). IUCN ed List of Threatened Species. Accessed October 02, 2012 at

Polite, C., T. Harvey. 2000. "Yellow-Cheeked Chipmunk Neotamias ochrogenys" (On-line). California Department of Fish and Game. Accessed November 15, 2012 at

Roberson, D. 2009. "Chipmunks" (On-line). Accessed November 15, 2012 at

Rosenberg, D., R. Anthony. 1993. Differences in Townsent's Chipmunk Populations between Second- and Old-Growth Forests in Western Oregon. The Journal of Wildlife Management, 57 No.2: 365-373. Accessed November 10, 2012 at

Sutton, D. 1987. Analysis of Pacific Coast Townsend Chipmunks (Rodentia: Sciuridae). The Southwestern Naturalist, 32/3: 371-376.

Sutton, D. 1995. Problems of Taxonomy and Distribution in Four Species of Chipmunks. Journal of Mammalogy, 76/3: 843-850.

Waldien, D., J. Hayes, M. Huso. 2006. Use of Downed Wood by Townsend's Chipmunks (Tamias townsendii) in Western Oregon. Journal of Mammalogy, 87/3: 454-460. Accessed October 05, 2012 at

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Fletcher, M. 2013. "Tamias ochrogenys" (On-line), Animal Diversity Web. Accessed July 23, 2014 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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