There are two subspecies of Siskiyou chipmunks that differ based on their size and color, one is found near the coast and one is located further inland. The coastal subspecies, Tamias siskiyou humboldti, is darker and browner, with lighter stripes, grayish undersides and pale gray patches behind their ears. While the inland population, Tamias siskiyou siskiyou, is light brown, with dark body stripes, creamy white undersides and a smoky colored rump and thighs, with a dark patch behind their eyes and a whitish patch behind their ears. Both subspecies molt seasonally. When the coastal population molts in June, their coat becomes tawnier, with paler stripes. When they molt again in the fall, their coat becomes thicker and darker, with pale gray stripes. The inland subspecies becomes more brightly colored after the spring. In the fall, these chipmunks develop darker, denser and duller fur in preparation for winter. Female Siskiyou chipmunks are generally larger. Siskiyou chipmunks have facial stripes that distinguish them from Allen's chipmunks and they are less gray than Townsend's chipmunks. (Sutton and Patterson, 2000)
Siskiyou chipmunks (Tamias siskiyou) are found in central to southern Oregon and northern California, near the Pacific coast. Their range is limited by natural barriers such as rivers and mountains. These barriers divide them from similar chipmunks, such as Townsend's chipmunks. (McIntire, 1984; Sutton and Patterson, 2000)
Siskiyou chipmunks are found in maritime climates, areas with heavy snow fall in the winter and dry summers. These chipmunks live in mature forests of sugar and Jeffrey pines, incense cedars and Douglas fir trees. Siskiyou chipmunks are found mostly in upland areas with dense forests and a thick tree canopy. However, they may also be found in areas that have been logged because the stumps, logs and piles of coarse, woody debris can be used for shelter and nesting. They make their homes in hollow trees, under fallen logs and in piles of leaves and wood. (Johnston and Anthony, 2008; Sutton and Patterson, 2000)
After emerging from hibernation, Siskiyou chipmunks mate in the spring. Populations living in low elevations usually breed in mid-April and animals found in lower elevations breed a few weeks later. Siskiyou chipmunks have a promiscuous mating system. (Sutton and Patterson, 2000)
Siskiyou chipmunks breed once a year, after about a 28 week gestation period; they typically have 4 to 6 offspring. The offspring stay in nests found in trees or in grass and moss-lined burrows, they are fed by their lactating mother for at least a few weeks. (; Sutton and Patterson, 2000)
Siskiyou chipmunks give birth in May and June. However, females are still lactating in June and July, which indicates that females care for their offspring for several weeks or months (Sutton and Patterson, 2000)
The lifespan of Siskiyou chipmunks is currently not known.
Their home range is generally small, ranging from about 2,000 to 40,000 meters squared. Most individuals stay in one general area but are capable of moving up to 5 km to find a suitable habitat. (; Hammerson, 2013)
Siskiyou chipmunks are known for having a distinct call of one long, intense syllable. Their call starts low in frequency, rises and falls again. ("Tamias siskiyou", 2013)
Siskiyou chipmunks are fungivores; they eat the mature fruiting bodies of mycorrhizal fungi that grow within plant roots. They also eat various plants, seeds, nuts and insects. Siskiyou chipmunks store food in a cache in preparation for the winter months. (; McIntire, 1984)
Siskiyou chipmunks have cryptic coloration, which means that their coloration is similar to their environment. They also hide beneath plant cover to avoid predator, which include various mammals, snakes, hawks and owls. (; Sutton and Patterson, 2000)
These chipmunks spread the seeds and fungal spores from their food through their feces, in this way they help maintain plant biodiversity. (McIntire, 1984)
There are no known adverse effects of Siskiyou chipmunks on humans.
As a fungivore, Siskiyou chipmunks spread fungal spores. Certain types of fungus can improve tree growth; therefore, these chipmunks indirectly supplement forest health and biodiversity, which can impact logging. (Jacobs and Luoma, 2008)
Currently, there are no known threats to the population of Siskiyou chipmunks.
Natalie Singleton (author), Indiana University-Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
1990. California Department of Fish and Game Book: Siskiyou chipmunk. Sacramento: California Department of Fish and Game.
2013. "Tamias siskiyou" (On-line). Smithsonian National Museum of Natural History: North American Mammals. Accessed April 05, 2013 at http://www.mnh.si.edu/mna/image_info.cfm?species_id=387.
Hammerson, G. 2013. "Neotamias siskiyou" (On-line). NatureServe Explorer. Accessed April 04, 2013 at http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Neotamias%20siskiyou.
Jacobs, K., D. Luoma. 2008. Small mammal mycophagy response to variations in green-tree retention. Journal of Wildlife Management, 72/8: 1747-1755.
Johnston, A., R. Anthony. 2008. Small-mammal microhabitat associations and response to grazing in Oregon. Journal of Wildlife Management, 72/8: 1736-1746.
McIntire, P. 1984. Fungus consumption by the Siskiyou chipmunk within a variously treated forest. Ecology, 65/1: 137-146.
Sutton, D., B. Patterson. 2000. Geographic variation of the western chipmunks Tamias senex and T. siskiyou, with two new subspecies from California. Journal of Mammalogy, 81/2: 299-316.