Allen's chipmunk

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Allen's chipmunk
Allen's chipmunk near Lake Almanor-2326.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Sciuridae
Genus: Neotamias
Species:
N. senex
Binomial name
Neotamias senex
(J. A. Allen, 1890)
Subspecies

N. s. pacifica(Sutton & Patterson, 2000)
N. s. senex(J. A. Allen, 1890)

Synonyms

Tamias senexJ. A. Allen, 1890

Allen's chipmunk (Neotamias senex), also known as the shadow chipmunk, is a species of chipmunk native to the western United States. [2] Occurring in California, Oregon, and Nevada, it is a common species of the Sierra Nevada. [3] [4] [5]

Description

Allen's chipmunk's total length measures about 229–261 mm (9.0–10.3 in), with a tail length of 90–111 mm (3.5–4.4 in). Adults weigh 66.8–108.5 g (2.36–3.83 oz), with females being larger than males on average as the species exhibits a dimorphism ration of 1.033. [4] The coastal subspecies (Neotamias senex pacifica) is characterized by an overall dark fur complexion with indistinct dorsal stripes, similar to that of Neotamias townsendii . The inland subspecies (Neotamias senex senex) have a much lighter complexion, with brownish-yellow fur tinged with smoky gray. [4] [5] During the summer and winter, it displays a distinctive black median dorsal stripe along its back. [5]

Distribution

The coastal subspecies is found solely in the redwood forest belt of California that extends from the Pacific coast to about 32 km (20 mi) inland, and ranges from the Eel River of Humboldt County in the south to the Klamath River of Del Norte County in the north. The inland subspecies's range starts at Shaver Lake, Fresno County and stretches northwards and westwards into the Sierra Nevada, Cascade, Warner, and Yolla Bolly ranges, and bordering the eastern-most boundary of the coastal subspecies' range. [5]

Habitat

Allen's chipmunk is a primarily arboreal species, inhabiting coniferous forests and their dense shrubbery, as well as areas of adjacent chaparral. [4] [5] It has been observed as the only chipmunk species to have a preference for old-growth, closed-canopy forests. [4] [6] Nests are typically created in fallen logs or hollow trees, particularly those of the ponderosa pine and the Jeffrey pine. [5] In the Sierra Nevada, nests have been found on top of partially broken-off trees as high as 27 m (88.6 ft) off the ground; these chipmunks have also been seen nesting in tree stumps and woodpecker holes. [4]

Elevation for the coastal subspecies ranges from sea level to around 150 m. [4] [5] For the inland subspecies, specifically around the Sierra Nevada, the chipmunks can commonly be found between 1,220–2,350 m (4,000–7,700 ft), and as high as 2900 m (9,500 ft) in Yosemite National Park. [4] [7]

Behavior

Allen's chipmunk exhibits a generally social nature. [4] It has a chip vocalization that typically consists of a rapid series of calls, with each call being another rapid series of 3–5 syllables. It has a mean call duration of 0.81 seconds with 0.39 seconds between each syllable; calls are of a medium frequency, with a minimum frequency of 4.59 kHz and a maximum of 12.98 kHz. [8] Its call has been observed as being used as an alarm call to possible threats. When approached by a predator, the chipmunk falls quiet and stays motionless, then resumes the alarm call when the predator has passed by. It has often been observed that when one chipmunk began to call, others would join in for up to 15 minutes. [4]

It is diurnal, and hibernates from November through to March; it is one of the few species of chipmunks in North America that undergo seasonal fat accumulation, increasing their weight by as much as 20% by November in order to make it through the winter months. [9] Before and after hibernation, the chipmunk tends to become quiet, secretive, and overall inactive. However as more chipmunks emerged from hibernation in the spring, the population has been observed to become loud and aggressive. [4]

Diet

Allen's chipmunk is omnivorous, with its diet consisting of fungi, insects, seeds, flowers, and fruit. Its diet is heavily dependent on geographical location and seasonality, mainly affecting the amount of fruit, flowers, and seeds consumed. Fungi, however, consistently serves as the chipmunk's primary food source, averaging around 60% of its food intake but getting as high as 99% when in virgin conifer forests. Allen's chipmunk uses its cheek pouches for food storage—primarily fungi—but has also been noted as the only species of chipmunk that collected the seeds that it ate. [4]

Lifecycle

Mating activity begins about one month after emergence from hibernation and lasts for about four weeks, roughly spanning the months of March to April, however geographic variation can occur. [4] The gestation period lasts about 28 days, with most litters being born in late May to early June, and are weaned for about 2 months until early August. [10] The number of offspring ranges from 3 to 5, with the average being about 4.5. Both males and females reach reproductive maturity at 10 months. [4]

Allen's chipmunk has two molts annually. The first follows shortly after breeding season, replacing the heavy, worn winter coat with a short, brighter coat. The second comes during late summer or early fall, before beginning the process of hibernation, replacing the light summer coat with a longer, softer, fuller, and more grayish coat. [4]

Allen's chipmunk has been observed to live as long as 8 years in the wild. However, due to a lack of data on Allen's chipmunk, specifics on its life expectancy are unknown. [11]

Natural predators of Allen's chipmunk include hawks, owls, foxes, coyotes, snakes, badgers, and weasels. [12]

Related Research Articles

<span class="mw-page-title-main">Chipmunk</span> Tribe of mammals (rodent (marmot))

Chipmunks are small, striped rodents of Sciuridae, the squirrel family; specifically, they are ground squirrels (Marmotini). Chipmunks are found in North America, with the exception of the Siberian chipmunk which is found primarily in Asia.

<span class="mw-page-title-main">Ground squirrel</span> Type of ground-dwelling rodent

Ground squirrels are rodents of the squirrel family (Sciuridae) that generally live on the ground or in burrows, rather than in trees like the tree squirrels. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as marmots or prairie dogs, while the smaller and less bushy-tailed ground squirrels tend to be known as chipmunks.

<span class="mw-page-title-main">Least chipmunk</span> Species of rodent

The least chipmunk is the smallest species of chipmunk and the most widespread in North America.

<span class="mw-page-title-main">Mountain beaver</span> Species of the genus Aplodontia

The mountain beaver is a North American rodent. It is the only living member of its genus, Aplodontia, and family, Aplodontiidae. It should not be confused with true North American and Eurasian beavers, to which it is not closely related; the mountain beaver is instead more closely related to squirrels, although its less-efficient renal system was thought to indicate greater relative antiquity for the species. There are seven subspecies of mountain beavers, six of which are found in California and three of which are endemic to the state.

<span class="mw-page-title-main">Alpine chipmunk</span> Species of rodent

The alpine chipmunk is a species of chipmunk native to the high elevations of the Sierra Nevada of California.

<span class="mw-page-title-main">Yellow-pine chipmunk</span> Species of rodent

The yellow-pine chipmunk is a species of order Rodentia in the family Sciuridae. It is found in parts of Canada and the United States.

<span class="mw-page-title-main">Gray-footed chipmunk</span> Species of rodent in the family Sciuridae

The gray-footed chipmunk is a terrestrial and forest-dwelling species of chipmunk and rodent in the family Sciuridae. It is endemic to New Mexico and in the Sierra Diablo and Guadalupe Mountains in the Trans-Pecos region of Texas in the United States. Its natural habitat are coniferous forests. First discovered in 1902, they are distinguished by the unique gray dorsal colouring on the hind feet, hence the common name. They demonstrate sexual dimorphism, and the female is larger than the male.

<span class="mw-page-title-main">Gray-collared chipmunk</span> Species of rodent

The gray-collared chipmunk is a species of rodent in the family Sciuridae. It is endemic to Arizona and New Mexico in the United States.

<span class="mw-page-title-main">Yellow-cheeked chipmunk</span> Species of rodent

The yellow-cheeked chipmunk, also known as the redwood chipmunk, is a species of rodent in the squirrel family, Sciuridae. It is endemic to areas near the coast of northern California in the United States where it inhabits coastal coniferous forest.

<span class="mw-page-title-main">Palmer's chipmunk</span> Species of rodent

Palmer's chipmunk is a species of rodent in the family Sciuridae, endemic to Nevada. Its natural habitat is temperate forests. It is threatened by habitat loss. It is named after Theodore Sherman Palmer, an American botanist and zoologist.

<span class="mw-page-title-main">Panamint chipmunk</span> Species of rodent

The Panamint chipmunk is a species of rodent in the squirrel family, Sciuridae. It is endemic to desert mountain areas of southeast California and southwest Nevada in the United States.

<span class="mw-page-title-main">Long-eared chipmunk</span> Species of rodent

The long-eared chipmunk, also called the Sacramento chipmunk or the four-banded chipmunk, is a species of rodent in the squirrel family, Sciuridae. It is endemic to the central and northern Sierra Nevada of California and Nevada in the United States. Long-eared chipmunks have the longest ears of all species of chipmunks.

<span class="mw-page-title-main">Colorado chipmunk</span> Species of rodent

The Colorado chipmunk is a species of chipmunk in the squirrel family Sciuridae. It is endemic to Colorado, Utah, Arizona and New Mexico in the United States.

The Siskiyou chipmunk is a species of rodent in the family Sciuridae. It is endemic to northern California and central Oregon in the United States.

<span class="mw-page-title-main">Sonoma chipmunk</span> Species of rodent

The Sonoma chipmunk is a species of rodent in the squirrel family Sciuridae. It is endemic to northwestern California in the United States. Members of Neotamias are characterized by having two premolars. N. sonomae has two subspecies: N. s. alleni and N. s. sonomae.

<span class="mw-page-title-main">Lodgepole chipmunk</span> Species of rodent

The Lodgepole chipmunk is a species of rodent in the family Sciuridae. It is found in the U.S. state of California at elevations from 1,500 to 3,000 metres. The Lodgepole chipmunk has a variety of common names including: Tahoe chipmunk, Sequoia chipmunk, Mt. Pinos chipmunk, and San Bernardino chipmunk.

<span class="mw-page-title-main">Uinta chipmunk</span> Species of rodent

The Uinta chipmunk or hidden forest chipmunk, is a species of chipmunk in the family Sciuridae. It is endemic to the United States. Formerly known as Tamias umbrinus, phylogenetic studies have shown it to be sufficiently distinct from the eastern chipmunk as to be placed in a separate genus, Neotamias. The same studies have also suggested that Palmer's chipmunk may actually be a subspecies of Uinta chipmunk, although the two are still generally regarded as separate species.

<i>Neotamias</i> Genus of rodents

Neotamias is a genus of chipmunks within the tribe Marmotini of the squirrel family. It contains 23 species, which mostly occur in western North America. Along with Eutamias, this genus is often considered a subgenus of Tamias.

<span class="mw-page-title-main">Ezo chipmunk</span> Subspecies of mammal

The Ezo chipmunk is a subspecies or local population of the Siberian chipmunk; it is found in what was once known as Ezo, namely Hokkaidō, Japan, and Sakhalin and the Southern Kuriles, Russia.

References

  1. ↑ Cassola, F. (2016). "Neotamias senex". IUCN Red List of Threatened Species . 2016: e.T42579A22268269. doi: 10.2305/IUCN.UK.2016-2.RLTS.T42579A22268269.en . Retrieved 17 November 2021.
  2. ↑ Jr, E. W. Jameson; Peeters, Hans J. (1988). Mammals of California: Revised Edition. ISBN   978-0-520-23582-3.
  3. ↑ "Shadow Chipmunk (Tamias senex) mSHCHx_CONUS_2001v1 Range Map - ScienceBase-Catalog". www.sciencebase.gov. Retrieved 2023-10-24.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Gannon, William L.; Forbes, Richard B. (1995-06-23). "Tamias senex". Mammalian Species (502): 1. doi: 10.2307/3504301 . ISSN   0076-3519.
  5. 1 2 3 4 5 6 7 Sutton, Dallas A.; Patterson, Bruce D. (May 2000). <0299:GVOTWC>2.0.CO;2 "Geographic Variation of the Western Chipmunks Tamias Senex and T. Siskiyou, with Two New Subspecies from California". Journal of Mammalogy. 81 (2): 299–316.
  6. ↑ Waters, J. R.; Zabel, C. J. (1998-12-03). "Abundances of Small Mammals in Fir Forests in Northeastern California". Journal of Mammalogy. 79 (4): 1244–1253. doi: 10.2307/1383015 . ISSN   1545-1542.
  7. ↑ Grinnel, Joseph; Storer, Tracy Irwin (1924). Animal Life in the Yosemite: An Account of the Mammals, Birds, Reptiles, and Amphibians in a Cross-section of the Sierra Nevada. University of California Press. p. 183.
  8. ↑ Gannon, W. L.; Lawlor, T. E. (1989-11-27). "Variation of the Chip Vocalization of Three Species of Townsend Chipmunks (Genus Eutamias)". Journal of Mammalogy. 70 (4): 740–753. doi:10.2307/1381708. ISSN   1545-1542.
  9. ↑ Hartson, Tamara (July 15, 1999). Squirrels of the West. Lone Pine Publishing.
  10. ↑ Wilson, Don E.; Ruff, Sue (October 15, 1999). Smithsonian Book of North American Mammals. UBC Press. ISBN   9780774807623.
  11. ↑ Nowak, Ronald M. (1999). Walker's Mammals of the World. Johns Hopkins University Press. doi:10.56021/9780801857898. ISBN   978-0-8018-5789-8.
  12. ↑ Winans, Marie; Avalos, Nancy (October 24, 2023). "Tamias senex Allen's Chipmunk". animaldiversity.org. Retrieved 2023-10-24.

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