Tamias panamintinusPanamint chipmunk

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Geographic Range

Tamias panamintinus is found in isolated populations in southeastern California and southwestern Nevada. The species was described from specimens collected from the Panamint Mountains of Death Valley National Park, California. In other parts of California, it occurs on the eastern slope of the southern Sierra Nevada Mountains and in desert ranges such as the Argus, Clark, Granite, Inyo, Kingston, Mescal, Providence, and White mountains. In Nevada, there are records from the Excelsior, Grapevine, Silver Peak, Spring, Sweetwater, and Wassuk, Wabuska mountain ranges. (Best, et al., 1994; Best, et al., 1994; California Fish and Game, 2003; Hirshfield and Bradley, 1977; Merriam, 1893; Roland and Wilson, 2002)

Habitat

Panamint chipmunks are commonly associated with piñon pine forests where they seek out rock outcroppings. These animals occur at elevations between 1,370 and 2,745 m. They prefer areas where soil cover is thin and granite cliffs and ledges are numerous. They reside in areas of high heat and arid conditions that other species of chipmunk are unable to tolerate. (Best, et al., 1994; Hall, 1981; Jameson, Jr. and Peeters, 2004; Merriam, 1893)

  • Range elevation
    1370 to 2745 m
    4494.75 to 9005.91 ft
  • Average elevation
    2060 m
    6758.53 ft

Physical Description

Panamint chipmunks are medium sized chipmunks with the total body length of females averaging 118.6 mm and that of males averaging 117.9 mm. Females are slightly larger than males, as is the case with other species of chipmunk. Weights are between 74 and 105 g.

During summer, pelage coloration is bright tawny with the anterior gray; whereas in the winter the fur is long and silky, with yellowish coloration and faded markings. The top of the head is light gray, with reduced dark facial stripes. The dorsal stripes are dark except for the middle stripe, which is usually brown; the outer stripes are similar in coloration to the body.

There are two subspecies described, T. panamintinus panamintinus, and T. panamintinus acrus. The larger of the subspecies is T. p. panamintinus. The colors of T. p. panamintinus are paler, with tawny sides, and grayer at the crown of the head, whereas T. p. acrus has sides that are brown in color. The skull of T. p. acrus is smaller mainly in the width and depth of the brain case; a shorter, narrower, and more pointed rostrum. Tamias panamintinus panamintinus has larger orbitals and a brain case that is longer posteriorly.

Panamint chipmunks share their habitat with other species of chipmunks. Tamias minimus, Tamias umbinus, and Tamias palmeri are commonly found in the same areas as T. panamintinus. However, the species are fairly easily distinguished.

Tamias minimus is small to medium in size, with a rostrum that is short and stout. Its coloration is varied, depending on the subspecies; the baculum is thin in the shaft and at the base.

Tamias umbrinus is medium to large with dark tones on the upper part of the body with a medium sized skull and a narrow braincase. The baculum is thick and short in the shaft with a widened base.

Tamias palmeri has grayish to tawny tones on the upper part of the body, a pale ocular stripe, with a shorter skull, rostrum, nasal, and upper incisors than T. umbrinus. The baculum is undistinguishable from the baculum of T. umbrinus.

Based on molecular data from the mitochondrial DNA of T. panamintinus, it is likely that Panamint chipmunks are most closely related to Tamias quadrimaculatus and T. minimus. (Best, et al., 1994; California Fish and Game, 2003; Good, et al., 2003; Hirshfield and Bradley, 1977; Piaggo and Spicer, 2001; Roland and Wilson, 2002; White, 1953)

Like many chipmunks, these animals are not active above ground on cold winter days. They are assumed to hibernate. Because of this, they should be considered heterothermic. However, because when they are active, as well as torpid, they maintain a constant body temperature. This makes them homoiothermic. Like all mammals, T. panamintinus is endothermic. (Wilson and Ruff, 1999)

  • Sexual Dimorphism
  • female larger
  • Range mass
    74 to 105 g
    2.61 to 3.70 oz
  • Average mass
    90 g
    3.17 oz
  • Range length
    85 to 240 mm
    3.35 to 9.45 in
  • Average length
    163 mm
    6.42 in

Reproduction

Details on the reproductive habits of Panamint chipmunks are scant. If they are like other members of their genus, they are probably polygynous. (Wilson and Ruff, 1999)

Panamint chipmunks breed from March to May. Gestation is about 36 days in this species. Young are typically born in late May to June. Litters usually range in size from 3 to 9 young, although a litter size of 4 to 6 young is more typical. Weaning occurs around the age of 5 weeks.

As in other chipmunks, the young are able to reproduce in the breeding season following their birth. In other species of chipmunks, young usally enter hibernation alone, and so are independent by the end of their first summer. It is likely that this species is similar. (Best, et al., 1994; Hirschfeld, 197; Wilson and Ruff, 1999)

  • Breeding interval
    These animals breed once annually.
  • Breeding season
    Mating occurs from March to May.
  • Range number of offspring
    3 to 9
  • Average gestation period
    36 days
  • Average weaning age
    5 weeks
  • Average age at sexual or reproductive maturity (female)
    10 months
  • Average age at sexual or reproductive maturity (male)
    10 months

Mothers care for their young in a nest located in a burrow. Maternal care extends from birth until shortly after weaning. During this period, the young go from being hairless, with eyes and ears shut, to fully-functional miniature adults. The mother provides her young with food and protection. Males are not known to engage in parental care. (Best, et al., 1994; Hirshfield and Bradley, 1977; Wilson and Ruff, 1999)

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

Lifespan/Longevity

The longevity of these animals has not been reported. However, it is likely to be similar to that seen in other members of the genus Tamias. As such, it is not likely to exceed 8 years, and is likely to be shorter. (California Fish and Game, 2003; Wilson and Ruff, 1999)

Behavior

Tamias panamintinus is diurnal, and can be spotted outside of its den during many hours of the day. These chipmunks are often seen running to a water source or sitting atop a rock, eating nuts. From such feeding stations, individuals can often see 100 m or more in any direction.

Panamint chipmunks do not often occur in open spaces, but stay rather close to rocks and trees. They are social within a family setting, with much maternal care invested in the young.

It is not clear whether these animals hibernate. They are often spotted in winter, but only on mild days. They are thought to hibernate when weather conditions become extremely harsh and food is scarce (observed in laboratory). However, this species is known to store food, which is likely consumed while individuals are remaining underground in the winter.

Panamint chipmunks are territorial. Intraspecific aggression occurs during all seasons, especially during spring breeding. (Best, et al., 1994; Hirshfield and Bradley, 1977)

The reasons for habitat zonation between T. panamintinus and T. palmeri are unclear. It may be a result of interspecific aggression, limited food availability, limited nesting sites, or other physiological needs. The strong correlation between juniper-piñon pine habitat and T. panamintinus occurrence suggests that the separation of these two species may a result of habitat specialization. (Best, et al., 1994; Hirschfeld, 197)

Home Range

Home ranges have not been described. However, if like other chipmunks, the home range of these animals probably does not greatly exceed one hectare. (Wilson and Ruff, 1999)

Communication and Perception

Tamias panamintinus uses vocalizations during courtship and other contexts. Young are able to make vocalizations within 12 to 18 hours of birth, and will make noises if separated from the mother.

All chipmunks make a variety of sounds. The lengths and patterns of vocalizations may be species specific, and can include chucks, chatterings, whistles, chips, chipperings, burst and sweeps. These are typically described by frequency and rate. Panamint chipmunks have a unique terminal pulse which following a chip, as well as lengthened syllables. (Best, et al., 1994)

Although not well studied in this species, other chipmunks are known to use visual communication, such as tail positioning and body posture. Tactile communication is also important during courtship and mating, as well as in the natal burrow. It is reasonable to assume that Panamint chipmunks are similar to other members of the genus in this regard. (Wilson and Ruff, 1999)

Food Habits

Panamint chipmunks are primarily granivores, but will consume seeds, fruits, green vegetation, arthropods, lichens, and bark. Fruits consumed are primarily piñon and juniper fruits found in the course of foraging on the ground, in shrubs, and trees. These animals often cache food for future use. If water is available they drink it, but access to free water is not necessary for survival, as enough water is available from the diet. (Hirschfeld, 197)

  • Animal Foods
  • carrion
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit

Predation

Typical chipmunk predators are raptors, weasels, coyotes, bobcats, and foxes. As members of the Order Rodentia, they are considered a vital part of the food chain. Although details for T. panamintinus are not available, it is likely that their predators are similar to those of other species in the area. (California Fish and Game, 2003)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Panamint chipmunks are a prey species. They probably contribute to some extent to the diets of their predators, although details on this interaction are not available in the literature. In addition, they probably play some role in seed dispersal and reforestation through their caching behavior. (Hirshfield and Bradley, 1977)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

These animals have no known direct economic impact on humans. However, because they help to disperse seeds, they may aid people by keeping forests healthy.

Economic Importance for Humans: Negative

There is no known negative impact on human economies caused by these chipmunks.

Conservation Status

Tamias panamintinus is not a large conservation concern. What concern there is stems from the small range of the species. This restricted range makes it important to conserve the habitat of these animals to ensure that they are present in the future. Panamint chipmunks are common in the areas they inhabit. Two of these areas are Death Valley National Park and the Mojave Preserve. These areas are federally protected land and because of this all of the animals inhabiting these areas are protected. A permit is required to trap, collect, or perform studies.

Contributors

Molly Peters (author), California State Polytechnic University, Pomona, Molly Wear (author), California State Polytechnic University, Pomona, John Demboski (editor, instructor), California State Polytechnic University, Pomona.

Nancy Shefferly (editor), Animal Diversity Web.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carrion

flesh of dead animals.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Best, T., R. Clawson, J. Clawson. 1994. Tamias panamintinus. Mammalian Species, 498: 1-7.

California Fish and Game, 2003. "California Habitat Wildlife Relationships System" (On-line). California Department of Fish and Game. Accessed October 18, 2005 at http://www.dfg.ca.gov/whdab/html/cwhr.html.

Good, J., J. Demboski, D. Nagorsen, J. Sullivan. 2003. Phylogeography and Introgressive Hybridization: Chipmunks (Genus Tamias) in the Northern Rocky Mountains. Evolution, 57(3): 1900-1916.

Hall, E. 1981. Mammals of North America. New York: Wiley.

Hirschfeld, J. 197. Reproduction, Growth, and Development of Two Species of Chipmunks: Eutamias panamintinus and Eutamias palmeri . Las Vegas: University of Nevada.

Hirshfield, J., W. Bradley. 1977. Growth and development of two species of chipmunks: Eutamias panamintinus and T. palmeri . Journal of Mammalogy, 58: 44-52.

Jameson, Jr., E., H. Peeters. 2004. Mammals of California. Berkeley: University of California Press.

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, 8: 129-138.

Merriam, C. 1942-49. Eutamias panamintinus. University of California Publications in Zoology, 48: 356-358.

Piaggo, A., G. Spicer. 2001. Molecular Phylogeny of the Chipmunks Inferred from Mitochondrial Cytochrome b and Chytochrome Oxidase II Gene Sequences. Molecular Phylogenetics and Evolution, 20(3): 335-350.

Roland, V., D. Wilson. 2002. Mammals of North America. Princetown, New Jersey: Princetown University Press.

White, J. 1953. The Baculum in the Chipmunks of Western North America. Museum of Natural History: University of Kansas Publications.

Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington: The Smithsonian Insititution Press in Association with the American Society of Mammalogists.