All the specimens of this species from the desert slope of the San
Gabriel Range are referred to the subspecies _perplexus_. They were
taken in brushy habitats between the elevations of 4500 and 7400 feet.
Throughout much of this area _perplexus_ was found only in certain
restricted areas more or less surrounded by inhospitable ground. For
example, at 7400 feet on Blue Ridge, they were found occasionally in the
strips of sagebrush and lilac brush which locally capped this ridge.
Often these patches of chaparral on Blue Ridge were surrounded by areas
unsuitable for kangaroo rats: on the Pacific slope, talus, oaks, and
yellow pines prevailed; on the ridge scattered yellow pine groves were
present; and on the steep desert slope there were yellow pines and white
firs. In Swarthout Valley _perplexus_ was found in flats that supported
basin sagebrush and _Haploppus_, while the coniferous forests to the
south, and pinyon-covered slopes to the north were uninhabited. On flats
supporting antelope brush and juniper, _perplexus_ was often common, but
it did not penetrate the chaparral of adjacent slopes grown to scrub oak
and mountain-mahogany. In general then, _perplexus_ was found in fairly
open brushy flats or slopes, even where these were surrounded by
unsuitable habitats.
Specimens of _D. agilis_ from the desert slope two miles east of
Valyermo are referrable to the subspecies _perplexus_. A series taken in
Cajon Wash at Devore, on the Pacific slope, is intermediate between
_agilis_, of the coastal slope of the San Gabriels, and _perplexus_ of
the desert slope, but approaches more nearly the later subspecies. Thus,
different subspecies of _D. agilis_ occur on opposite slopes of the San
Gabriel Mountains, with intergradation taking place in the Cajon Pass
area and probably also at the west end of the Mountains.
Both scrub oak acorns and juniper berries were found in the cheek
pouches of this subspecies, and one immature individual taken in
Swarthout Valley had its cheek pouches stuffed with approximately 550
seeds of brome grass.
On November 13, 1951, at 7500 feet on Blue Ridge, a small juvenile was
taken; it must have been born not earlier than September.
_Specimens examined._--Total, 17, distributed as follows: Los
Angeles County: 2 mi. E Valyermo, 4600 ft., 3; 5 mi. E Valyermo,
1; 1 mi. E Big Pines, 6600 ft., 6; 1 mi. S and 2 mi. W Big
Pines, 7400 ft., 2. San Bernardino County: Cajon Wash, 1/2 mi.
SW Devore, 2200 ft., 5.