Tamias speciosus

Geographic Range

The range of Tamias speciosus is contained primarily within California. Populations occupy the eastern side of the Sierra Nevada, and in southern California, the disjunct San Bernardino, San Jacinto, and San Gabriel mountains. Lodgepole chipmunks extend as far north as Toulume and Nevada Counties, with unconfirmed presence further north. The species in also found in the Lake Tahoe region of California and Nevada.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Lodgepole chipmunks are found in subalpine mixed conifir forests containing lodgepole pine, red fir, and Jeffery pine. Other woodland vegetation includes white fir, Douglas fir, ponderosa pine, sugar pine, incense cedar, and California black oak. Tamias speciosus typically occurs at elevations between 1,500 and 3,300 m, with the greatest density of populations occuring between 2,400 and 3,000 m.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

Physical Description

Tamias speciosus is a small sciurid , typically weighing between 50 and 70 g. These animals measure from 197 to 212 mm in length. Tail length is reported at 13 to 22 mm. As in other chipmunks, females are slightly larger than males.

Tamias speciosus is a brightly colored, medium-sized chipmunk compared to others of the genus. It is easily distinguished from sympatric and parapatric relatives by its remarkably prominent facial and dorsal stripes. The dark cheek and submolar facial stripes are blacker with some brown and broader than in other neighboring species. The submolar stripes extend from the rostrum to the ear and are central below the eyes. The dark dorsal stripes strongly contrast with the light dorsal stripes. The black median stripe may fade to brown across the shoulder area. The white medial stripes are slightly yellow, whereas the white lateral stripes are much brighter and more prominent. These chipmunks nearly to completely lack a dark outer lateral stripe. The crown of the head is usually brown and sprinkled with grey. The sides of the head can be yellowish-tawny to brown in the summer. There is a white patch behind the ears, and the underside of the tail is cinnamon through most of the length with black near the tip.

The incisors of lodgepole chipmunks are short and straight, helping to distinguish these chipmunks from other species in the area. The dental formula of T. speciosus is 1-0-2-3/1-0-1-3.

In areas of sympatry, the size and shape of genital bones may provide the most diagnostic features of these animals. The baculum is 2.1 to 3.2 mm in length and the distal 2/3 of the shaft is strongly compressed.

Molecular differences with related species may be used in identification, since T. speciosus is sometimes confused with Tamias amoenus based solely on morphological diagnostics.

Chipmunks are endothermic hibernators. Their body temperature changes seasonally, so they can be considered heterothermic. However, since individuals maintain a constant body temperature in any given season, they can also be called homoiothermic.

• Other Physical Features
• endothermic endothermic
• heterothermic heterothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

When males are ready to mate, the scrotum is black and the testes are in a pendulous position. Both females and males use chattering vocalization and visual cues to attract mates, such as flipping their tails and using various body postures.

Although data on the mating system of this species are not available, most members of the genus Tamias for which mating systems have been described are polygynous. It is likely that T. speciosus is similar.

Tamias speciosus breeds during May and early June. The gestation period is about one month, after which a litter of 3 to 6 pups is born. Young chipmunks are typically poorly developed at birth. Lactation lasts for 1 month. Young are independent shortly after weaning, and typically disperse in the autumn of their birth year. These chipmunks reach reproductive maturity the following spring.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

Young are born in spring or early summer. Mothers lactate for about a month, at which time they stop caring for their young. Males are not known to provide any parental care in this species.

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

Lifespan/Longevity

Not much is known about T. speciosus lifespan. Individuals of this species are usually expected to only live through one breeding season, which is about a year. Mortality may be due to predation or to low temperatures, as many of these chipmunks are thought to freeze to death.

In spite of low average lifespan, individuals may live for up to 4 years in the wild and 5 years in captivity.

Behavior

Tamias speciosus is extremely furtive and shy. These chipmunks are not particularly vocal or conspicuous compared to other members of the genus . They are seldom seen or heard.

Field studies of interspecific aggression indicate that T. speciosus is aggressive to its sympatric and parapatric relatives, whereas in laboratory studies T. speciosus tends to be subordinate to other members of the genus. Both field and laboratory studies indicate high intraspecific aggression.

Tamias speciosus is diurnal and undergoes hibernation during the winter months until about March or early April. These chipmunks are somewhat arboreal, but spend much of their time on the ground gathering and caching food, especially in summer and autumn.

• Key Behaviors
• arboreal arboreal
• scansorial
• terricolous
• diurnal diurnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• territorial territorial

Home Range

Home range size ranges between .25 and .5 hectares

Communication and Perception

Lodgepole chipmunks use a small repertoire of vocalizations to communicate. These include a high “whisk”, a shrill “tsew”, a rapid “pst-pst-pst-a-ku”, a chip, a chippering, a chuck, and a whistle. In courtship, T. speciosus uses a chattering vocalization and visual cues. Tail flipping and various body postures are used during courtship, inter- and intra-specific aggression, and during encounters with potential predators.

Although not specifically reported, we may assume that tactile communication occurs during mating, as well as between mothers and their young.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Lodgepole chipmunks are omnivorous, eating a wide range of seeds, nuts, berries and insects. They also eat other arthropods, fungi, and small vertebrates. Tamias speciosus individuals consume leaves, flowers, pollen, fruit, and garbage, when such items are available. They are known to be great robbers of eggs from bird nests, and they cache food.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• mammals
• eggs
• insects
• terrestrial non-insect arthropods

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit
• pollen
• flowers

• Other Foods
• fungus

• Foraging Behavior
• stores or caches food stores or caches food

Predation

Predators of lodgepole chipmunks include coyotes , Cooper's hawks , and red-tailed hawks . Other predators of T. speciosus are grey foxes , other foxes bobcats , and martens .

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Tamias speciosus consumes truffles of ectomycorrhizal fungi. These fungi aid forest ecosystems by increasing their water and nutrient uptake and by facilitating forest succession. Tamias speciosus plays a major role in the health and succession of forest ecosystems by dispersing viable fungal spores to new patches as well as being important seed and pollen dispersers.

Tamias speciosus is also an important part of food webs, in which it serves as both predator and prey.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Humans profit from the lodgepole chipmunks through their effects on their ecosystem. Tamias speciosus keeps down pests that could harm plants and other organisms. They have a mutualism with ecotomycorrhizal fungi and with many plant species for which they disperse seeds. Tamias speciosus also provides enjoyment for humans who view them in nature. There may be some economic value in breeding these animals for the pet trade.

• Positive Impacts
• pet trade pet trade
• food food
• research and education
• controls pest population

Economic Importance for Humans: Negative

Tamias speciosus is known to be a host for Yersinia pestis (plague) and for various ectoparasites, such as fleas, ticks, and lice. Besides plague, these parasitic organisms can harbor potentially dangerous diseases such as rabies. There is a direct economic cost when humans must be treated for these diseases.

• Negative Impacts
• injures humans
  • bites or stings
  • causes disease in humans causes disease in humans
  • carries human disease

Conservation Status

According to most sources, T. speciosus has no special conservation status. IUCN lists this species as a lower risk animal. In spite of this, it is important to maintain their habitat to assure that the species is maintained in the future.

Additional Links

Encyclopedia of Life

Contributors

Vivian Quesada (author), California State Polytechnic University, Pomona, Amy Chambers (author), California State Polytechnic University, Pomona, John Demboski (editor, instructor), California State Polytechnic University, Pomona.

Nancy Shefferly (editor), Animal Diversity Web.

References

Best, T., R. Clawson, J. Clawson. 1994. Tamias speciosus. Mammalian Species , 478: 1-9.

Blankenship, D., G. Bradley. 1985. Electrophoretic comparison of two Southern California chipmunks ( Tamias obscurus and Tamias merriami ). Southern California Academy of Sciences , 84/1: 48-50.

Chappell, M. 1978. Behavioral factors in the altitudinal zonation of chipmunks ( Eutamias ). Ecology , 59/3: 565-579.

Good, J., J. Demboski, D. Nagorsen, J. Sullivan. 2003. Phylogeography and introgressive hybridization: chipmunks (Genus Tamias ) in the Northern Rocky Mountains. Evolution , 57/8: 1900-1916.

Heller, H., D. Gates. 1971. Altitudinal zonation of chipmunks ( Eutamias ): Energy budgets. Ecology , 52/3: 424-433.

Heller, H. 1971. Altitudinal zonation of chipmunks ( Eutamias ): Interspecific aggression. Ecology , 52/2: 312-319.

Ingles, L. 1965. Mammals of the Pacific States: California, Oregon, Washington . Stanford, California: Stanford University Press.

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

Merriam, C. 1893. Descriptions of eight new ground squirrels of the genera Spermophilus and Tamias from California, Texas, and Mexico. Proceedings of the Biological Society of Washington , VIII: 129-138.

Meyer, M., M. North, D. Kelt. 2005. Short-term effects of fire and forest thinning on truffle abundance and consumption by Neotamias speciosus in the Sierra Nevada of California. Canadian Journal of Forest Research , 35: 1061-1070.

Piaggio, A., G. Spicer. 2001. Molecular phylogeny of the chipmunks inferred from mitochondrial cytochrome b and cytochrome oxidase II gene sequences. Molecular Phylogenetics and Evolution , 20/3: 335-350.

Pyare, S., W. Longland. 2001. Patterns of ectomycorrhizal-fungi consumption by small mammals in remnant old-growth forests of the Sierra Nevada. Journal of Mammalogy , 82/3: 681-689.

Sharples, F. 1983. Habitat use by sympatric species of Eutamias . Journal of Mammalogy , 64: 572-579.

Sutton, D. 1995. Problems of taxonomy and distribution in four species of chipmunks. Journal of Mammalogy , 76/3: 843-850.

Townsend, C., M. Begon, J. Harper. 2003. Essentials of Ecology 2nd edition . Massachusetts, USA: Blackwell Science, Inc..

White, J. 1953. The baculum in the chipmunks of Western North America. University of Kansas Publications, Museum of Natural History , 5/35: 611-631.