Tamias palmeri

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.

• Biogeographic Regions
• nearctic nearctic
  • native native

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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• chaparral chaparral
• forest forest
• mountains mountains

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.

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.

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.

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

• Sexual Dimorphism
• female larger

Reproduction

The mating system of these animals has not been reported. However, other chipmunks tend to be polygynous. Tamias palmeri may be similar.

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.

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

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.

• 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
  • 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.

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.

• Key Behaviors
• terricolous
• diurnal diurnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• solitary solitary
• territorial territorial

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.

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.

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

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

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.

• Primary Diet
• omnivore omnivore

• Animal Foods
• mammals
• eggs
• insects

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

• Other Foods
• fungus

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

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.

• Anti-predator Adaptations
• cryptic 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.

• 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.

Additional Links

Encyclopedia of Life

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.

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 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.