Mammal Species of the World
- Original description: Gambel, W., 1848. Proceedings of the Academy of Natural Sciences of Philadelphia, 4:77.
endemic to a single state or province
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (250-20,000 square km (about 100-8000 square miles)) Los Angeles Basin and foothills of San Gabriel and San Bernardino mountains in Ventura, Los Angeles, and Riverside counties north to Santa Barabra County and through the southern Sierra Nevada, including Mount Pinos, Tehachapi and San Gabriel mountains, and northern San Fernando Valley (Sullivan and Best 1997). Populations extending southward into Baja California are now allocated to Dipodomys simulans (Sullivan and Best 1997).
Length: 32 cm
Weight: 77 grams
Size in North America
Average: 302 mm males; 295 mm females
Range: 285-320 mm males; 277-305 mm females
Average: 72 g males; 66 g females
Range: 66-72 g males; 63-78 g females
Dipodomys stephensi lacks a white or light spot at the base of the ear pinna. The oval auditory bullae (when viewed from above) are oval in D. agilis, kidney shaped in D. simulans (Jameson and Peeters 2004).
California Montane Chaparral and Woodlands Habitat
This taxon can be found in the California montane chaparral and woodlands, a near coastal ecoregion in Central and Southern California, USA. This ecoregion is disjunctive, with a major element in Southern California and another along the Monterey County coast. The ecoregion encompasses most of the Transverse Range that includes the San Bernardino Mountains; San Gabriel Mountains; portions of the Santa Ynez and San Rafael Mountains; Topatopa Mountains; San Jacinto Mountains; the Tehachapi, Greenhorn, Piute, and Kiavah Mountains that extend roughly northeast-southwest from the southern Sierra Nevada; and the Santa Lucia Range that parallels the coast southward from Monterey Bay to Morro Bay.
The California montane chaparral and woodland ecoregion consists of a complex mosaic of coastal sage scrub, lower chaparral dominated by chamise, upper chaparral dominated by manzanita, desert chaparral, Piñon-juniper woodland, oak woodlands, closed-cone pine forests, yellow pine forests, sugar pine-white fir forests, lodgepole pine forests, and alpine habitats. The prevalence of drought-adapted scrub species in the flora of this ecoregion helps distinguish it from similar communities in the Sierras and other portions of northern California. Many of the shared Sierra Nevadan species typically are adapted to drier habitats in that ecoregion, Jeffrey Pine (Pinus jeffreyi) being a good example.
Oak species are an important component of many chaparral and forest communities throughout the ecoregion. Canyon Live Oak, Interior Live Oak, Tanbark Oak (not a true Quercus species), Engelmann Oak, Golden-cup Oak, and Scrub Oak are some examples. Mixed-conifer forests are found between 1371 to 2896 meters elevation with various combinations and dominance of incense cedar, sugar pine, and white fir, Jeffrey Pine, Ponderosa Pine, and mountain juniper. Subalpine forests consist of groves of Limber Pine (Pinus flexilis), Lodgepole Pine, and Jeffrey Pine. Very old individual trees are commonly observed in these relict subalpine forests. Within this zone are subalpine wet meadows, talus slope herbaceous communities, krumholz woodlands, and a few small aspen groves.
In addition to these general vegetation patterns, this ecoregion is noted for a variety of ecologic islands, communities with specialized conditions that are widely scattered and isolated and typically harbor endemic and relict species. Examples include two localities of Knobcone Pine (Pinus attenuata) on serpentine soils, scattered vernal pools with a number of endemic and relict species, and isolated populations of one of North America’s most diverse cypress floras, including the rare Gowen Cypress (Cupressus goveniana goveniana) restricted to two sites on acidic soils in the northern Santa Lucia Range, Monterey Cypress (Cupressus macrocarpa) found only at two coastal localities near Monterey Bay, and Sargent Cypress (Callitropsis sargentii LR/LC) restricted to serpentine outcrops. Monterey Pine (Pinus radiata) is also restricted to three coastal sites near Monterey Bay.
The ecoregion is also home to a few endemic or near-endemic mammalian vertebrates, such as the White-eared Pocket Mouse (Perognathus alticolus EN), a mammal known only to two disjunct mountain ranges in southern California: San Bernardino Mountains in San Bernardino County (ssp. alticolus), and the Tehachapi Mountains, in Kern, Ventura, and Los Angeles counties. The near-endemic fossorial Agile Kangaroo Rat (Dipodomys agilis) is found in the southern disjunctive unit of the ecoregion, and is known only to the Los Angeles Basin and foothills of San Gabriel and San Bernardino mountains in Ventura, Los Angeles, and Riverside counties north to Santa Barbara County and through the southern Sierra Nevada, including Mount Pinos, Tehachapi and San Gabriel mountains, and northern San Fernando Valley. Non-endemic mammals found in the ecoregion include Botta's Pocket Gopher (Thomomys bottae) and Trowbridge's Shrew (Sorex trowbridgii). Some larger vertebrate predators can be found in the ecoregion, including Puma (Puma concolor), Bobcat (Lynx rufus), Coyote (Canis latrans), and Ringtails (Bassariscus astutus).
The ecoregion boasts five endemic and near-endemic amphibians, largely Plethodontid salamanders. Some specific salamander taxa found here are the endemic Tehachapi Slender Salamander (Batrachoseps stebbinsi VU), known from isolated sites in the Caliente Creek drainage, Piute Mountains, and Kern County, California along with scattered populations in the Tehachapi Mountains to Fort Tejon, Kern County; the near-endemic Blackbelly Slender Salamander (Batrachoseps nigriventris); the Monterey Ensatina (Ensatina eschscholtzii); the Channel Islands Slender Salamander (Batrachoseps pacificus), endemic to a narrow range restricted solely on Anacapa, Santa Cruz, Santa Rosa, and San Miguel islands; and the Arboreal Salamander (Aneides lugubris), found only in California and Baja California. A newt found here is the Coast Range Newt (Taricha torosa). Anuran taxa in the ecoregion include the Foothill Yellow-legged Frog (Rana boylii NT); the Southern Mountain Yellow-legged Frog (Rana muscosa EN), a California endemic occurring in several disjunctive populations; and the Northern Red-legged Frog (Rana aurora).
The California montane chaparral and woodlands ecoregions contains a number of reptiles such as the Coast Horned Lizard (Phrynosoma coronatum), who ranges from Northern California to Baja California. Also found here is the Sagebrush Lizard (Sceloporus graciosus); the Western Fence Lizard (Sceloporus occidentalis); the Southern Alligator Lizard (Elgaria multicarinata); and the Side-blotched Lizard (Uta stansburiana). The Two-striped Garter Snake (Thamnophis hammondii) is a restricted range reptile found near-coastally from Monterey County, California southward to Baja California.
The California Condor once inhabited much of the ecoregion, with the western Transverse Range acting today as a refuge for some of the last wild populations, after considerable conservation efforts, especially in the Los Padres National Forest. The Heermann's Gull (Larus heermanni NT) is found in coastal areas of the ecoregion.
- C. Michael Hogan & World Wildlife Fund. 2014."California montane chaparral and woodlands". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed.Mark McGinley.
- Michael G.Barbour, Todd Keeler-Wolf, Allan A.Schoenherr. 2007. Terrestrial vegetation of California. University of California Press. 712 pages
Habitat and Ecology
Comments: This species is primarily montane, occupying chaparral-covered slopes upward to coniferous forests (Best et al. 1996). This species prefers easily excavated sandy or gravelly soils for constructing burrows, typically on steep slopes. Abundance increases following fires that create open space (Price and Waser 1984). Nests are in underground burrows.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Comments: Probably similar to other closely related species that feed primarily on seeds but also eat some insects and green vegetation.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: This species is represented by many occurrences or subpopulations (Sullivan and Best 1997), but some of them are not extant.
10,000 - 1,000,000 individuals
Comments: Total adult population size is unknown but probably exceeds 10,000.
Life History and Behavior
Lifespan, longevity, and ageing
No information available, but probably produces an average of 2 young per litter.
Molecular Biology and Genetics
Barcode data: Dipodomys agilis
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Download FASTA File
Statistics of barcoding coverage: Dipodomys agilis
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: Occurs in southern California from Santa Barbara County and the southern Sierra Nevada to the Los Angeles area; conservation status is uncertain, but many populations probably have been extirpated or depleted due to habitat destruction caused by urbanization.
Global Short Term Trend: Relatively stable to decline of 30%
Comments: Currently, area of occupancy, number of subpopulations, and population size probably are declining, but the rate of decline is unknown.
Global Long Term Trend: Decline of 30-50%
Comments: Specific data on long-term trend are lacking, but extent of occurrence, area of occupancy, number of subpopulations, and population size probably have declined.
Degree of Threat: Medium
Comments: Many populations probably have been extirpated or depleted due to urbanization and related habitat destruction (Sullivan and Best 1997). This is an ongoing threat as human populations in the region expand.
Global Protection: Few to several (1-12) occurrences appropriately protected and managed
Comments: Probably several occurrences are in protected areas such as state parks.
Agile kangaroo rat
Relatively little information has been published on the natural history, life history, ecology, or behavior of the agile kangaroo rat. The species appears to be part of the Californian kangaroo rat radiation, which is derived from a common ancestor with Ord's kangaroo rat. Best compared 19 morphological measurements from specimens from 34 populations across the species range, and concluded that the species is monotypic. An observational study found distinct habitat differences between the agile and Stephens's kangaroo rats, with the agile preferring more shrubs and lighter soils.
- Linzey, A.V. & Hammerson, G. (2008). "Dipodomys agilis". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved 2 February 2010.
- Patton, J. L. (2005). "Family Heteromyidae". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. p. 844. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Hafner, John C., Jessica E. Light, David J. Hafner, Mark S. Hafner, Emily Reddington, Duke S. Rogers, and Brett R. Riddle. 2007. "Basal Clades and Molecular Systematics of Heteromyid Rodents." Journal of Mammalogy 88 (5) (October 1): 1129-1145.
- Best, Troy L. 1983. "Intraspecific Variation in the Agile Kangaroo Rat (Dipodomys agilis)." Journal of Mammalogy 64 (3): 426-436. doi:10.2307/1380355.
- Price, Mary V., William S. Longland, and Ross L. Goldingay. 1991. "Niche Relationships of Dipodomys agilis and D. stephensi: Two Sympatric Kangaroo Rats of Similar Size." American Midland Naturalist 126 (1) (July 1): 172-186. doi:10.2307/2426161.
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Names and Taxonomy
Comments: Dipodomys simulans formerly was regarded as conspecific with D. agilis. Sullivan and Best (1997) found significant morphological differences between the two chromosomal forms of D. agilis (in the former sense) and divided D. agilis into two species, Dipodomys agilis (2n = 62) and Dipodomys simulans (2n = 60). Baker et al. (2003) and Patton (in Wilson and Reeder 2005) adopted this split.
Best et al. (1996) examined genic and morphological variation in D. agilis, D. elephantinus, and D. venustus and concluded that D. agilis is not conspecific with D. elephantinus or D. venustus and that D. elephantinus should be regarded as a subspecies of D. venustus. Baker et al. (2003) and Patton (in Wilson and Reeder 2005) adopted this taxonomy.