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Tamias palmeriPalmer's chipmunk

By Yvonne Ybarra and Karina Zaragoza

Geographic Range

Palmer's chipmunks, Tamias palmeri, are found solely in the state of Nevada. This species is restricted to the Spring Mountains west of Las Vegas. (Hirshfeld, 1975; Ruff, 1999)

Habitat

Palmer’s chipmunks are found at elevations between 2,100 and 3,600 m in the Spring Mountains. They are most abundant between 2,400 and 2,550 m. Tamias palmeri is commonly found in coniferous forests that contain juniper-piñon pine, fir-pine, and bristlecone pine communities. In the Spring Mountains, Panamint chipmunks, Tamias panamintinus, inhabit lower elevation forests. (Hirshfeld, 1975; Nevada Department of Wildlife, 2005)

  • Range elevation
    2100 to 3600 m
    6889.76 to 11811.02 ft

Physical Description

The total body length varies from 210 to 223 mm. The tail measures between 86.5 and 101.5 mm. The body weight ranges from 50 to 69.4 g. (Ruff, 1999)

Adults have distinct solid black and solid white dorsal stripes like other chipmunks, with the sides of the body tawny and tan. The ventral surface of the tail is much paler. The top of the head and rump are gray.

Tamias palmeri exhibits a narrow and flattened brain case, long upper incisors, larger cheek teeth and nearly parallel zygomatic arches. The length of the baculum is approximately 4 mm. Baculum size can be used to distinguish between T. palmeri from T. panamintinus, which has a baculum approximately 3 mm long. (; Best, 1993; Hirshfeld, 1975; White, 1953)

These animals appear to hibernate facultatively. Although they may dwell in their underground burrows when weather is cold, on warm winter days they are often seen running around on top of the snow. They may enter torpid states when it is cold, but wake often to snack on cached food. We assume here that they are homoiothermic and heterothermic, in that they maintain a constant body temperature which is dependent upon whether they are active or torpid. (Hirshfeld, 1975; Ruff, 1999)

  • Sexual Dimorphism
  • female larger
  • Range mass
    50 to 69.4 g
    1.76 to 2.45 oz
  • Range length
    210 to 223 mm
    8.27 to 8.78 in

Reproduction

The mating system of these animals has not been reported. However, other chipmunks tend to be polygynous. Tamias palmeri may be similar. (Hirshfeld, 1975; Ruff, 1999)

Palmer’s chipmunks are reproductively active from April through July. Mating occurs during March, when males exhibit scrotal testes. Gestation is between 30 and 33 days. The average number of embryos per litter ranges between 3 and 6.

Hairless young are born underground during mid-summer and are weaned by August. They usually appear above ground at the end of July, or around the age of 5 weeks, and are able to eat nuts, seeds, and berries within a week of their emergence from the natal burrow.

Like other chipmunks, these animals are capable of breeding in the season following their birth. Young are independent by the end of summer. (Nevada Department of Wildlife, 2005; Hirshfeld, 1975; Ruff, 1999; White, 1953)

  • Breeding interval
    These animals breed once per year.
  • Breeding season
    Breeding occurs in March.
  • Range number of offspring
    3 to 6
  • Range gestation period
    30 to 33 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

Because chipmunks rear their young in burrows, little is known about their parental care. However, in most species in the genus, males play no role in parental care. Females nurse, groom, and protect the young in the natal burrow. Although hairless and helpless at birth, these animals develop rapidly and are generally independent by the end of the summer. (Best, 1993; Hirshfeld, 1975; 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
    • protecting
      • female

Lifespan/Longevity

Depending on food availability, weather conditions and predator/prey situations, the lifespan of T. palmeri is between one to four years. (Nevada Department of Wildlife, 2005; Nevada Department of Wildlife, 2005)

  • Typical lifespan
    Status: wild
    1 to 4 years

Behavior

Palmer's chipmunks are diurnal, ground-dwelling mammals. They sometimes occupy nests in trees, but these are not common. Foraging occurs along the floors of canyons and rocky outcroppings.

These animals can show extreme aggression and territoriality, especially during the breeding season.

Hibernation typically occurs, although it consists of bouts of torpor interspersed with active times when weather permits. These small mammals cache food to eat during winter. (Hirshfeld, 1975; Ruff, 1999)

Home Range

They usually live on the ground, in rock crevices or fallen logs. Within their home ranges, they dig burrows that can be up to 30 feet in length. Further information on home range size is not available, although most chipmunks inhabit areas of less than one hectare. (Hirshfeld, 1975)

Communication and Perception

The name chipmunk is derived from the chipping noises these animals make with their teeth. Loud trilling type noises are used to call to potential mates, as well as in defending territories.

In addition to vocal communication, most species of chipmunk use visual cues, such as body posture and tail positioning, in communicating with other members of their species. Tactile communication is likely to figure prominently in maternal interactions with young, as well as in mating. The role of chemical communication has not been described in these animals. (Wilson and Ruff, 1999)

Food Habits

Palmer's chipmunks are omnivorous. Their diet includes seeds, fruits, various plants, fungus, and invertebrates such as worms, snails and insect larvae. Bird eggs and small mice are occasionally eaten. From spring through autumn, the diet consists mainly of seeds, fruits, greens and flowers. Invertebrates are not part of the diet during spring, but may be found in other seasons.

In the autumn, Palmer's chipmunks gather and store food to be used during winter. (Hirshfeld, 1975; Ruff, 1999)

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

Predation

Palmer’s chipmunks may be eaten by carnivores such as coyotes, fox, weasels, and raccoons. Feral dogs and cats may also prey upon them. Other predators include birds of prey and snakes. (Hafner, et al., 1995; Nevada Department of Wildlife, 2005)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Tamias palmeri plays an important role in the food chain. It also helps in seed dispersal for various forms of plants. These chipmunks have a symbiotic relationship with mychorrizal fungi. (Hafner, et al., 1995)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

These animals have a very restricted range, and do not often come in contact with humans. As such, it is unlikely that they have any positive impact on human economies.

Economic Importance for Humans: Negative

These animals have no reported negative impact on humans.

Conservation Status

Palmer’s chipmunks are not endangered, but the species is listed as a population of concern in Nevada. Since this species is restricted to the Spring Mountains, human impact due to habitat loss and increasing recreational activity is of potential concern. IUCN lists these animals as vulnerable. (Hafner, et al., 1995; Nevada Department of Wildlife, 2005)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Yvonne Ybarra (author), California State Polytechnic University, Pomona, Karina Zaragoza (author), California State Polytechnic University, Pomona, John Demboski (editor), California State Polytechnic University, Pomona.

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.

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

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

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.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

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

solitary

lives alone

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.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

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. 1993. Tamias palmeri. Mammalian Species, 443: 1-6.

Hafner, D., E. Yensen, G. Kirkland, J. Hall, J. Cook, D. Nargorsen. 1995. "Chipmunks" (On-line). Accessed November 16, 2005 at http://www.iucn.org.

Hirshfeld, J. 1975. Reprodution, Growth, and Development of Two Species of Chipmunk: Eutamias panamintinus and Eutamias palmeri . University of Nevada, Las Vegas: University of Nevada.

Nevada Department of Wildlife, 2005. "In the Wild Animals of Nevada" (On-line). Nevada Department of Wildlife. Accessed October 19, 2005 at http://www.ndow.org.

Ruff, S. 1999. Palmer's chipmunk| Tamias palmeri . Pp. 372-373 in D Wilson, S Ruff, eds. The Smithsonian Book of North American Mammals. Washington: The Smithsonian Institution Press in Association with the American Society of Mammalogists.

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

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

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