Mammal Species of the World
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endemic to a single state or province
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (<100-250 square km (less than about 40-100 square miles)) Southern portion of Gabilan Range, from vicinity of Pinnacles to near Hernandez, in San Benito and eastern Monterey counties, California; elevation about 390 meters.
Length: 34 cm
Weight: 91 grams
Size in North America
Average: 326 mm males; 323 mm females
Range: 310-336 mm males; 305-323 mm females
Average: 85 g
Range: 79-91 g
Comments: Slopes, flats, ridgetops with friable soil in mixed and chamise chaparral in oak/pine woodland zone. Typically under dense vegetation (sympatric DIPODOMYS HEERMANNI occupies adjacent open habitat) (Best 1986). Young are born 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 D. HEERMANI which feeds primarily on seeds but also eats insects and green vegetation in the spring.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 5
2500 - 10,000 individuals
Comments: Rare within range. Estimate is a guess based on the most narrowly defined taxonomic concept of the species.
Life History and Behavior
Young are born at least during spring and summer. Probably produces an average of 2 young per litter.
National NatureServe Conservation Status
Rounded National Status Rank: N2 - Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: T2 - Imperiled
Reasons: Small range in western California; probably adapted to periodic fire in chaparral community, as is D. AGILIS; habitat is under little threat of development; structurally indistinguishable animals are found at widespread localities in adjacent mountains east and south.
Global Short Term Trend: Relatively stable (=10% change)
Comments: Probably stable.
Degree of Threat: C : Not very threatened throughout its range, communities often provide natural resources that when exploited alter the composition and structure over the short-term, or communities are self-protecting because they are unsuitable for other uses
Comments: Fire is a major threat to alter habitat, but fire probably poses no major threat to the species.
Management Requirements: Reduce fuel and maintain habitat through appropriate range and fire management; prevent excessive grazing and destructive wildfires.
Biological Research Needs: Data on all aspects of life history and demography are needed.
Global Protection: Few (1-3) occurrences appropriately protected and managed
Comments: Pinnacles National Monument contains an extant population; degree of specific protection is unknown, however.
Big-eared kangaroo rat
Names and Taxonomy
Comments: Formerly was recognized as a distinct species. 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 ELEPHANTINUS or VENUSTUS and that ELEPHANTINUS should be regarded as a subspecies of D. VENUSTUS.
See Ryan (1989) for phylogenetic analysis of Heteromyidae based on myology. Characterisitics of the upper premolar indicate that the genus DIPODOMYS, as now conceived, is diphyletic (Dalquest et al. 1992).
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