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Townsend's chipmunk

Tamias townsendii

What do they look like?

Townsend's chipmunks are brown with stripes on their faces and backs. Their backs are dark brown and have darker and lighter stripes. Their faces have two gray and three brown stripes. Their bellies are creamy white or gray, and their ears are black in front and gray behind. Their tail is dark brown and gray, and darker at the tip. When they run, they hold their tails up. Townsend's chipmunks have brighter fur in the summer. In May and August, they lose all of their fur and regrow it. Young chipmunks have similar fur color to adults. (Edelman and Koprowski, 2006; Headley and Sells, 2005; Levenson and Hoffman, 1984; Smithsonian Institution, 2012; Sutton, 1993; Thorington and Ferrell, 2006)

Townsend's chipmunks are larger than many other chipmunks. They measure 22 to 38 cm long, and 25.5 cm on average. This length includes their tail, which is about 7 to 17 cm long. Townsend's chipmunks weigh 60 to 118 g, and 75 g on average. Females are 2% to 6% larger than males, and there are usually more females than males. The skulls of Townsend's chipmunks look different from chipmunks in eastern North America because they have a small upper premolar tooth. (Edelman and Koprowski, 2006; Headley and Sells, 2005; Levenson and Hoffman, 1984; Smithsonian Institution, 2012; Sutton, 1993; Thorington and Ferrell, 2006)

  • Sexual Dimorphism
  • female larger
  • Range mass
    60 to 118 g
    2.11 to 4.16 oz
  • Average mass
    75 g
    2.64 oz
  • Range length
    22 to 38 cm
    8.66 to 14.96 in
  • Average length
    25.5 cm
    10.04 in

Where do they live?

Townsend's chipmunks live in the northwestern United States. They are found from the the Rogue River in southern Oregon to southwestern British Columbia along the Pacific coast. They live in places that have weather that is like being near the ocean. ("Tamias townsendii", 2012; Sutton, 1993)

What kind of habitat do they need?

Townsend's chipmunks live mostly in thick forests of hardwood trees and pine trees. Inside forests, they usually live along the edges of streams, rivers, or lakes. They also often live in places with lots of shrubs. Other times, they live in much more open areas, like in places where forests have been cut down. This gives them protection as well as a food source. They are found along the ocean coast to mountain areas in Oregon. When they are getting ready to nest, they for places with loose rocks where they find shelter. (Headley and Sells, 2005; Linzey and Hammerson, 2008; Sutton, 1993)

  • Range elevation
    0 (low) m
    0.00 (low) ft

How do they reproduce?

Townsend's chipmunks mate for 2 weeks in spring. Like most chipmunks, they do not form a pair bond and females only males have multiple mates. (Edelman and Koprowski, 2006; Thorington and Ferrell, 2006)

Townsend's chipmunks breed once a year for 2 weeks right after they wake up from hibernation. This means that reproduction happens between late spring and early summer, when food is available and the weather is better. Also, they young can develop in the summer and get ready for the winter. ("AnAge entry for Tamias townsendii", 2005; Sutton, 1993)

Baby Townsend's chipmunks develop in the bodies of their mothers for 28 days and then are born between May and June. Females have 3 to 6 young at a time and give birth in their burrows. At first, the young have no hair or teeth. Their eyes are closed, their ears are folded, their feet are webbed, and their skin is translucent. They weigh around 3.5 g. After 10 days, they have some hair on their back, but their eyes are still closed. They can move around a little bit by pulling and pushing with their front limbs. After 20 days, they have fur and teeth at the front of their mouths, and are more active. They come above ground in July, when food is available and the weather is warmer. They drink milk from their mothers for 50 days until they weigh about 35 g. After 90 days, they are considered adults. At 353 days, adults reach sexual maturity and Townsend's chipmunks can reproduce the following summer. ("AnAge entry for Tamias townsendii", 2005; Sutton, 1993)

  • How often does reproduction occur?
    Townsend's chipmunks breed once a year.
  • Breeding season
    Townsend's chipmunks breed for 2 weeks in spring, usually in late April.
  • Range number of offspring
    3 to 6
  • Average gestation period
    28 days
  • Average weaning age
    50 days
  • Average time to independence
    90 days
  • Average age at sexual or reproductive maturity (female)
    353 days
  • Average age at sexual or reproductive maturity (male)
    353 days

When Townsend's chipmunks are born, they are not able to see or move very well. Their mothers protect them in their burrows and feed them. She feeds them milk from her body until they are able to leave the burrow and be independent. (Headley and Sells, 2005)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

How long do they live?

The record for the longest life of a Townsend's chipmunk in captivity is 9.3 years. Another Townsend's chipmunk supposedly lived 10.2 years in captivity, but this was not well documented. In the wild, they usually live 2 to 7 years, and are expected to live for around 5 years. The number of Townsend's chipmunks can be limited by how much food is available. ("AnAge entry for Tamias townsendii", 2005; Headley and Sells, 2005; Sutton, 1993; Weigl, 2005)

  • Range lifespan
    Status: wild
    2 to 7 years
  • Range lifespan
    Status: captivity
    10.2 (high) years
  • Typical lifespan
    Status: wild
    7 (high) years
  • Average lifespan
    Status: wild
    5 years
  • Average lifespan
    Status: captivity
    7 hours

How do they behave?

Townsend's chipmunks are active in the day, especially in later morning and early afternoon. They are more active when the weather is warmer, between March and late November. They spend most of their time eating and gathering food that they store in their burrow for the winter. They often use paths with cover so they can stay hidden from predators. Townsend's chipmunks live by themselves and are aggressive toward each other or with other chipmunks. They each have their own burrow, which can be up to 10 m long. If they live at high elevation where it snows, they often hibernate during the winter. ("Tamias townsendii", 2012; Edelman and Koprowski, 2006; Encyclopedia of life, 2012; Fuller and Blaustein, 1990; Harestad, 1991; Sutton, 1993; Thorington and Ferrell, 2006; Waldien, et al., 2006)

  • Range territory size
    0.8 (high) km^2
  • Average territory size
    0.5 km^2

Home Range

The area where Townsend's chipmunks travel and feed in can be up to 0.5 ha in size. They only defend the center of the area, which is 9 to 12 m from the burrow. The size of their home range can also depend on their size, the number of chipmunks in the area, and where there is food. Females are bigger, so they usually have bigger home ranges. (Edelman and Koprowski, 2006)

How do they communicate with each other?

Townsend's chipmunks get information about their environment by seeing, hearing, and smelling. They communicate by making noises, making aggressive postures, and touch. They make a lot of alarm calls, which is not common among solitary animals. They make more alarm calls to warn their siblings or other relatives, which they recognize from sniffing and grooming when they are youg. (Fuller and Duszynski, 1997)

What do they eat?

Townsend's chipmunks eat a wide variety of foods. One of their favorite foods are fungi that live underground and have a strong smell, like truffles. They eat a lot of mushrooms, but their diet changes depending on what kinds of foods are available. In the summer, they mostly eat berries like blackberries, salal berries, and thimble-berries. In the fall, they mostly eat seeds like maple seeds, thistle seeds, grain seeds, conifer seeds, and also acorns, huckleberries, grasses and roots. Fungi that live underground and have a strong smell are one of their favorite foods, especially in winter. Townsend's chipmunks usually find food on the ground, but sometimes climb in trees as well. They carry food from their foraging area to their burrow in pouches in their cheeks. (Encyclopedia of life, 2012; Headley and Sells, 2005; Sheppard, 1989; Sutton, 1993)

  • Animal Foods
  • insects
  • Plant Foods
  • roots and tubers
  • seeds, grains, and nuts
  • fruit
  • Other Foods
  • fungus

What eats them and how do they avoid being eaten?

Townsend's chipmunks warn others using alarm calls. Because they are small and their fur blends into their environment, they are are difficult for predators to see and catch. They also hide out in covered places. Townsend's chipmunks are eaten by weasels, minks, bobcats, house cats, foxes, martens, skunks, hawks, owls, and snakes. (Encyclopedia of life, 2012; Harestad, 1991; Waldien, et al., 2006)

What roles do they have in the ecosystem?

Townsend's chipmunks eat mostly plants, and are eaten by several predators. They spread seeds throughout their environment. They spread them in their feces because they are hard to digest, and also store them in their burrows. If some of the seeds are left at the end of the winter, they can sprout in the spring. Townsend's chipmunks may also disperse fungi by carrying their reproductive cells on their feet, and spreading them with their feces. Townsend's chipmunks can get infected with some kinds of parasites like protozoans. (Edelman and Koprowski, 2006; Fuller and Blaustein, 1990; Headley and Sells, 2005)

  • Ecosystem Impact
  • disperses seeds
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • protozoans (Eimeria)

Do they cause problems?

Townsend's chipmunks can spread fungi that are harmful to the seeds of pine trees. This could cause some problems for the forestry business. (Headley and Sells, 2005; Sutton, 1993)

How do they interact with us?

Townsend's chipmunks eat fungi, which affects the ecology of the forest. Fungi add nutrients to the soil and improve its quality. (Headley and Sells, 2005; Sutton, 1993)

Are they endangered?

Townsend's chipmunks are not threatened or endangered, and are actually pretty common. Chemicals sprayed on Douglas fir trees in the 1980's in British Columbia caused their populations to temporarily decline. In a forest with older trees, there are about 0.6 to 1.1 Townsend's chipmunks per hectare. In forests regrowing after being cut down, there can be 2 to 4 times as many. (Sullivan, 1990)

Some more information...

Contributors

Anne-Claire Acquisto (author), University of Alaska Fairbanks, Laura Prugh (editor), University of Alaska Fairbanks, Catherine Kent (editor), Special Projects.

References

2005. "AnAge entry for Tamias townsendii" (On-line). AnAge : the Animal Ageing and Longevity Database. Accessed November 16, 2012 at http://genomics.senescence.info/species/entry.php?species=Tamias_townsendii.

2012. "Tamias townsendii" (On-line). USA National Phenology Network. Accessed December 09, 2012 at http://www.usanpn.org/Tamias_townsendii.

Edelman, A., J. Koprowski. 2006. Influence of female-biased sexual size dimorphism on dominance of female Townsend's chipmunks. Canadan Journal of Zoology, 84: 1859-1863. Accessed November 16, 2012 at http://ag.arizona.edu/~squirrel/CJZ%20dimorph%20in%20Chips%2007.pdf.

Encyclopedia of life, 2012. "Facts about Tamias townsendii" (On-line). Encyclopedia of Life. Accessed November 16, 2012 at http://eol.org/pages/4466570/details.

Fuller, C., A. Blaustein. 1990. An investigation of sibling recognition in a solitary sciurid, Townsend's Chipmunk, Tmaias townsendii. Behaviour, 112/No1/2: 36-52. Accessed November 16, 2012 at http://www.jstor.org/stable/10.2307/4534827.

Fuller, C., D. Duszynski. 1997. Eimeria (Protozoa : Eimeriidae) from North American Sciurids, Glaucomys sabrinus and Tamias townsendii : with a description of a new species. The Journal of Parasitology, 83/3: 467-470. Accessed November 16, 2012 at http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1176&context=parasitologyfacpubs.

Harestad, A. 1991. Spatial behaviour of Townsend's chipmunks and habitat structure. Acta theoriologica, 36: 247-254. Accessed November 15, 2012 at http://rcin.org.pl/Content/11759/BI002_26813_Cz-40-2_Acta-T36-nr21-247-254_o.pdf.

Headley, S., S. Sells. 2005. "Townsend's Chipmunk" (On-line). Accessed December 06, 2012 at http://extension.oregonstate.edu/catalog/pdf/ec/ec1580.pdf.

Levenson, H., R. Hoffman. 1984. Systematic relationships among taxa in the Townsend Chipmunk group. The southwestern Naturalist, 29/2: 157-168. Accessed November 16, 2012 at http://www.jstor.org/stable/10.2307/3671022.

Linzey, A., G. Hammerson. 2008. "Tamias townsendii (Townsend's chipmunk)" (On-line). The IUCN Red List of Threatened Species. Accessed November 16, 2012 at http://www.iucnredlist.org/details/42584/0.

Robertson, S. "How do Chipmunks communicate?" (On-line). eHow. Accessed November 16, 2012 at http://www.ehow.com/info_10069070_chipmunks-communicate.html.

Sheppard, D. 1989. "Les suisses et les tamias" (On-line). Faune et flore du pays. Accessed November 16, 2012 at http://www.hww.ca/fr/especes/mammiferes/les-suisse-et-les-tamias.html.

Smithsonian Institution, 2012. "North American Mammals - Townsend's Chipmunk" (On-line). Smithsonian National Museum of Natural History. Accessed November 16, 2012 at www.mnh.si.edu/mna/image_info.cfm?species_id=391.

Sullivan, T. 1990. Demographic responses of small mammal populations to a herbicide application in coastal coniferous forest: population density and resiliency. Canadian Journal of Zoology, 68: 874-883. Accessed December 09, 2012 at http://www.nrcresearchpress.com/doi/pdf/10.1139/z90-127.

Sutton, D. 1993. Tamias Townsendii. The American Society of Mammalogists, 432: 1-6.

Thorington, R., K. Ferrell. 2006. Squirrels : the animal answerguide. Baltimore, MD, USA: Johns Hopkins University Press.

Waldien, D., J. Hayseb, M. Husob. 2006. Use of downed wood by Tonsend's Chipmunks (Tamias townsendii) in Western Oregon. Journal of Mammalogy, 87/3: 454-460. Accessed December 06, 2012 at http://www.bioone.org/doi/pdf/10.1644/05-MAMM-A-136R1.1.

Weigl, R. 2005. Longevity of Mammals in Captivity; from the Living Collections of the World.. Stuttgart: E. Schweizerbart'sche.

 
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Acquisto, A. 2013. "Tamias townsendii" (On-line), Animal Diversity Web. Accessed October 30, 2014 at http://www.biokids.umich.edu/accounts/Tamias_townsendii/

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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