Squirrels of the World

Tamias alpinus 315

Tamias alpinus Merriam, 1893

Alpine Chipmunk

description: This small chipmunk is pale in coloration.
The venter is orangish, and the back has four whitish stripes.
The lateral stripes are wide and white, but often pale. T. alpi-
nus is smaller than all sympatric (or parapatric) species (e.g., T.
amoenus, T. quadrimaculatus, T. senex, T. speciosus, and T. umbri-
nus), except T. minimus. T. alpinus is distinguished from T.
minimus by the former’s shorter tail and larger ears and skull.

size: Female—HB 106.4 mm; T 75.5 mm.
Male—HB 104.6 mm; T 69.5 mm.
Sex not stated—HB 105.3 mm; T 78.5 mm; Mass 35.8 g.

distribution: This species’ range is limited to a narrow
portion (less than 20,000 km^2 ) of the higher elevations of the
Sierra Nevada in central California, from Tuolumne to Tu-
lare counties (USA).

geographic variation: None.

conservation: IUCN status—least concern. Population

trend—stable.

habitat: T. alpinus is found in the Sierra Nevada of Califor-

nia (USA), at elevations between 2300 and 3900 m, primarily

in the alpine life zone (more than 3000 m in altitude), but

also in the Hudsonian and Canadian life zones. It is a highly

insular species, whose prevalence and occurrence probably

depend on the physical structure of its habitat. This consists

primarily of meadows, talus slopes, boulder fi elds, open

stands of lodgepole pine (Pinus contorta), and small patches

of whitebark pine (P. albicaulis). T. alpinus spends consider-

able time in rocky habitats, which may allow a quick and

effi cient escape from predators. Their habitat is generally

xeric, as it is exposed to full sun, although maximum daily

temperatures do not exceed 20°C.

natural history: Alpine chipmunks will consume some

pine seeds, but they depend more heavily on the smaller

seeds of sedges, grasses, and forbs found throughout their

habitat. Most information on their diet is based on details

recorded from the cheek pouches of a few individuals; the

cheek pouches of one animal contained approximately 5000

seeds. It is assumed that this species larder-hoards, like

other species of Tamia s; however, early natural-history ob-

servations suggest scatter-hoarding behavior as well. T. alpi-

nus is also considered a predator of bird eggs and nestlings,

and this species may limit the breeding range of the Asian

rosy fi nch (Leucosticte arctoa). No nests have been reported

for alpine chipmunks. The range of T. alpinus overlaps with

those of fi ve other species of Tamia s, but alpine chipmunks

are fully sympatric with only one, T. speciosus. Two species

of lice (Neohaematopinus pacifi cus and Hoplopleura arboricola)

and one species of mite (Ornithonyssus sylviarum) parasitize

it; no predators are reported, although the short-tailed wea-

sel (Mustela erminea) is known from the habitat of T. alpinus.

Alpine chipmunks are territorial; aggressive displays are

common toward conspecifi cs and often include a range of

vocalizations (e.g., high-pitched calls, and lower-pitched

“chucks” and “chips”) as well as vertical tail displays. They

are reported to enter hibernacula in late October and emerge

Tamias Illiger, 1811

This genus contains 25 species. Chipmunks are com-
monly considered to be either a single genus, Tamia s, or
three genera—Tamia s, Eutamias, and Neotamias. In the latter
case, Ta mia s would contain the eastern chipmunk, Eutamias

would consist of the Siberian chipmunk, and Neotamias

would include the remaining 23, mostly western, species.

Here we treat the chipmunks as a single genus, Tamia s.