328 Tamias obscurusTamias obscurus J. A. Allen, 1890
California Chipmunk, Dusky Chipmunk
description: The pelage is marked by fi ve dark chestnut-
colored dorsal stripes, which are distinct in the winter pel-
age but drab and inconspicuous by spring. Compared with
T. merriami, T. obscurus is slightly smaller in body size and
cranial dimensions, and it has a grayer venter; they are sym-
patric in parts of their ranges in southern California.
SIZE: Female—HB 128.3 mm; T 117.0 mm.
Male—HB 125.3 mm.
Sex not stated—HB 124.1 mm; T 103.3 mm; Mass 69.0 g.
distribution: This species’ range is fragmented; it extends
from isolated populations in the San Bernardino and San
Jacinto mountains in San Bernardino County, California
(USA) to separate populations in Sierra de San Francisco and
central Baja California, México.
geographic variation: Three subspecies are recognized.
T. o. obscurus—central fragment of the species’ range that
extends from extreme southern California (USA) south-
ward for about 300 km into Baja California (México). The
upperparts are gray suff used with brown. The dorsal
stripes are inconspicuous. The tail is shorter.
T. o. davisi—occupies the two northernmost fragments of
the species’ distribution in southern California (USA).
The throat and upper chest are gray.
T. o. meridionalis—isolated in a small area of central Baja
California (México). This is a smaller and grayer form.conservation: IUCN status—least concern. Population
trend—stable.habitat: This species’ range consists of at least four dis-
tinct fragments; within each of these, populations appear to
be even further fragmented by low-lying deserts. T. obscurus
is found primarily in arid pinyon-juniper (Pinus, Juniperus)
and pine-oak (Pinus, Quercus) stands in the desert areas of
southern California to central Baja California, usually at
elevations between 1200 and 3000 m. However, specifi c
patterns of habitat use vary with location and elevation.
In southern California, for example, isolated populations
of T. o. davisi occupy pine-fir-oak (Pinus, Abies, Quercus)
forests of the transition zone; pinyon-juniper (Pinus, Juni-
perus) stands of the upper Sonoran zone; lodgepole pine–
chinquapin (Pi nus contorta, Castanopsis sempervirens) commu-
nities of the Canadian life zone; and even live oak–chaparral
(Quercus chrysolepis, Adenostoma [chamise]) habitats at eleva-
tions less than 1500 m. T. obscurus also often occurs on rock
outcrops or talus slopes throughout its range, especially in
the San Pedro Mártir Mountains (Baja California, México).
At the extreme southern edge of the species’ range, T. o. me-
ridionalis occupies palm-cactus stands of the lower Sonoran
life zone.natural history: T. obscurus is ac t ive yea r-round a nd, li ke
other chipmunks, is diurnal. Its daily activity is bimodal,
with peaks in the early morning and late in the day. DetailsTamias obscurus. Photo courtesy Nicolas Ramos-Lara.