The giant kangaroo rat has an extremely small range limited to the west-central region of the U.S. state of California. Specifically, it is currently found only as far north and west as Fresno County and as far east and south as San Luis Obispo and Bakersfield Counties

Biogeographic Regions: nearctic (Native )

endemic to a single state or province

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (5000-20,000 square km (about 2000-8000 square miles)) The range is confined to a narrow strip along the southwestern border of the San Joaquin Valley and a few nearby valleys to the west, including the Carrizo and Elkhorn plains and upper Cuyama Valley, with scattered colonies in the Ciervo, Kettleman, Panoche, and Turney Hills, and the Panoche Valley (Grinnell 1922, Hall 1981, Williams and Kilburn 1991, Williams et al. 1993). Historical range extended from Merced County south to the base of the Tehachapi Mountains in Kern County, and west to eastern San Luis Obispo County and extreme northern Santa Barbara County (Williams et al. 1993). Elevational range extends to about 868 meters (400-2,850 feet).

The population is currently fragmented into six major geographic units: 1) the Panoche region in western Fresno and eastern San Benito counties; 2) Kettleman Hills in Kings County; 3) San Juan Creek Valley in San Luis Obispo County; 4) western Kern County in the area of the Lokern, Elk Hills, and other uplands around McKittrick, Taft, and Maricopa; 5) Carrizo Plain in eastern San Luis Obispo County; and 6) Cuyama Valley in Santa Barbara and San Luis Obispo counties (see USFWS 1998). These major units are fragmented into more than 100 smaller populations, many of which are isolated by several miles of barriers such as steep terrain with plant communities unsuitable as habitat, or agricultural, industrial, or urban land without habitat for this species (USFWS 1998).

The giant kangaroo rat is the largest of all kangaroo rats and has a body length ranging from 15 to 20 cm and a tail length of 18 to 21.5 cm. Unlike many other kangaroo rats, D. ingens possesses five toes on each hind foot, a white stripe running across its hindquarters, and a white belly. It also has a distinctive tail that is dark colored on the top and bottom with white lines on both sides.

Length: 35 cm

Weight: 180 grams

Other kangaroo rats in California have only four toes on the hind foot or usually have a head and body length of less than 130 mm (Jameson and Peeters 2004).

• Terrestrial

Scrub desert and piedmont are the basic habitats of giant kangaroo rats. They prefer relatively flat homogenous terrain with shrubs and rocks being almost totally absent. Typical habitat is stretches of easily excavated sandy loam covered with annual grasses and herbs.

Terrestrial Biomes: desert or dune ; chaparral

Comments: Habitat consists of gently sloping and level piedmont plains and (formerly) areas supporting saltbush and perennial grasses; habitat now is dominated by introduced annuals, with many shrubs in some areas. The species occupies areas of sparse vegetative cover and well-drained soils and slope generally less than 9% (Williams and Kilburn 1991) (sometimes up to 22%; USFWS 1998), often in areas that are heavily grazed by cattle and sheep (Williams and Kilburn 1991). This kangaroo rat prefers semi-arid slopes at the head of draws in barren shrubless areas, with loose, easily diggable, sandy loam soils. When inactive, it occupies underground burrows. It is absent from areas continuously in dry-land cultivation and from irrigated fields but may recolonize fallow dry-land grain fields if there are colonies on uncultivated land nearby (Williams and Kilburn 1991). Habitats listed in order of decreasing favorability: 1) annual grassland association in areas with less than 5-6 inches annual rain, and level to gently sloping ground, 2) alkali desert scrub association in areas with less than 5-6 inches annual rain, sandy loam soils, and level to gently sloping ground, 3) friable soils of sand, loam, clay loam or gravelly in areas with the above charcateristics, and 4) slopes of 10-15 degrees with the above characteristics and located near colonies in more favorable habitats (D. Williams, pers. comm.). Young are born in 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.

Limited data suggest that effective dispersal may extend over several kilometers and that individuals can disperse through highly inhospitable habitat (see USFWS 1998).

Giant kangaroo rats are granivorous and prefer to eat the seeds and green parts of native desert plants. They are also known to eat grain and the seeds of commercially grown plants if fields are nearby. Food is cured in shallow pits or piles on the ground called 'haystacks.' It is then stored in the central cave of their burrow. They extract all the water they need from these sources.

Comments: Feeds on seeds, especially those of Lepidium nitidum, Oenothera, Bromus rubens, and Erodium cicutarium. Also eats some green herbaceous vegetation and occasionally insects. In some localities, gathers dry grass into "haystacks" to cure, later removing seeds for storage in underground burrows. Also temporarily buries seeds in ground before storing in burrow.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 6 - 20

Comments: The extant distribution includes more than 100 more or less distinct populations, but most of these represent fragments of a formerly more continuous distribution. There are six major geographic units, each of which could be regarded as a single occurrence or subpopulation.

10,000 to >1,000,000 individuals

Comments: Total adult population size is unknown but probably exceeds 100,000 during average conditions. Adult population size varies substantially with drought and plant productivity (USFWS 1998); density ranges from 1 to 110 individuals per hectare (see USFWS 1998).

Population density is 5-50 per ha (18-69/ha in the larger and denser colonies, Williams and Kilburn 1991). Home range is about 60-350 sq m; strict intrasexual avoidance indicated (basically solitary and territorial). Extant population sizes are small; from fewer than 10 to several hundred individuals (Braun 1985).

In spring, areas around occupied burrows have a more lush growth of herbaceous vegetation than do areas between burrow systems; this growth is eventually removed by grazing by livestock and/or kangaroo rats (Williams and Kilburn 1991).

Digging and feeding activity promote the establishment of exotic weeds, which in turn are a favored food source (Schiffman 1994).

Comments: Emerges to forage soon after sunset in spring. Spends a little less than 2 hours per night above ground actively foraging in spring-summer (Braun 1985).

Breeding takes place in late winter or early spring. Gestation is 28 to 32 days in length. Anywhere from one to six young are born in a burrow in the spring, three being average. The young are cared for by their mothers and fathers and are weaned in 15 to 25 days. They reach sexual maturity in 60 to 84 days. They then leave the burrow and seek new territories within the colony to dig burrows of their own. Giant kangaroo rats have been known to live up to 9.8 years in the wild.

Limited data indicate that the reproductive season may extend from January through May (Williams and Kilburn 1991) (February to June or perhaps later according to Biosystems Analysis 1989). Gestation lasts about 1 month. Litter size is 3-6 (Biosystems Analysis 1989); modal litter size probably is 4 (Williams and Kilburn 1991). Young are weaned at 4 weeks (Matthews and Moseley 1990). Flexible mating system (Hekkala, no date).

• 2000
  Critically Endangered
• 1996
  Critically Endangered
  (Baillie and Groombridge 1996)
• 1994
  Indeterminate
  (Groombridge 1994)
• 1990
  Indeterminate
  (IUCN 1990)
• 1988
  Indeterminate
  (IUCN Conservation Monitoring Centre 1988)

The giant kangaroo rat was designated an endangered species by the California Department of Fish and Game (CDFG) in the early 1980s and is currently restricted to about 2% (under 17,000 hectares) of its historic range. The CDFG, together with the Nature Conservancy and the U.S. Bureau of Land Management, manages the Carrizo Plain Natural Area, which contains ninety percent of remaining habitat. Although protected in this area, giant kangaroo rats will likely be eliminated from all other areas unless habitat loss caused by urban and agricultural development in central California is stopped.

US Federal List: endangered

CITES: no special status

IUCN Red List of Threatened Species: endangered

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G2 - Imperiled

Reasons: Confined to southern California; most populations occupy relatively small areas of suitable habitat; habitat still being lost to various kinds of development; recent protection on the Carrizo Plain has alleviated threats somewhat; lack of appropriate habitat management on conservation lands may be resulting in habitat degradation in some areas.

Other Considerations: Threats have eased significantly since Endangered listing and acquisition of much of extant habitat on Carrizo/Elkhorn plains.

Global Short Term Trend: Decline of 10-30%

Comments: Within the area of currently occupied habitat, populations have expanded and declined with changing weather patterns since 1979; at their peak in 1992 to 1993, there probably were about 6 to 10 times more individuals than at their low point in spring of 1991, when a majority of the 11,145 hectares probably was uninhabited and most of the rest was inhabited by less than 10 percent of peak numbers (see USFWS 1998 for sources).

Global Long Term Trend: Decline of 30-50%

Comments: The huge colonies described in historical literature no longer exist. Extant habitat comprises only about 1.8 percent of the historical habitat (Williams 1992, USFWS 1998).

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: The decline is largely a result of conversion of habitat to agricultural uses, combined with additional loss of habitat to industrial uses (e.g., petroleum exploration and extraction) and urbanization, and population reductions and extirpations from rodenticide use (aimed at California ground squirrel and historically at kangaroo rats) (Williams 1992, USFWS 1998). Possibly excessive livestock grazing may have contributed to the decline in some areas (livestock may crush near-surface burrows and comptete for food with kangaroo rats) (see USFWS 1998). Between 1972 and 1980 most of the remaining habitat was converted from native vegetation to cultivated agricultural crops due in part to an abundance of irrigation water supplied by recently completed water delivery systems.

More recently, conversion of habitat to agricultural uses has slowed substantially, but urban and industrial developments, petroleum and mineral exploration and extraction, new energy and water conveyance facilities, and construction of communication and transportation infrastructures continue to destroy habitat and increase the threats to the species by reducing and further fragmenting populations (USFWS 1998). Habitat degradation due to lack of appropriate habitat management on conservation lands, especially lack of grazing or fire to control density of vegetation (including shrubs) may be a threat (Williams and Germano 1993).

Biological Research Needs: Data are needed on demography, dispersal, and reproduction.

Global Protection: Several (4-12) occurrences appropriately protected and managed

Comments: Habitat is protected to varying degrees at Carrizo Plain National Monument, U.S. Department of Energy Naval Petroleum Reserves in western Kern County, and certain BLM lands. Parcels in the Lokern area of western Kern County have been protected by the California Energy Commission, California Department of Fish and Game, and The Nature Conservancy.

Habitat for three of the six regional populations (Cuyama Valley, Kettleman Hills, and San Juan Creek Valley) include no public or conservation lands; all are small and vulnerable to extirpation from demographic and random catastrophic events (e.g., drought, flooding, fire), and inappropriate land uses that would degrade or destroy habitat (USFWS 1998).

Needs: Key to protection is an adequate understanding of compatible land uses and management
prescriptions that provide optimum habitat conditions (Williams and Germano 1993).

See USFWS (1998) for specific protection, management, and monitoring needs.

The burrow complexes of adults create very soft heaps of dirt that can collapse under the pressure exerted by livestock or a human. Because of this, sheep and cattle tend to avoid areas containing burrows; therefore, land inhabited by the rats is deemed less valuable to ranchers.

While providing no direct economic benefits, giant kangaroo rats help maintain the desert habitat in which they live by feeding on and collecting seeds. Kangaroo rats in general were popularized in Walt Disney's film, The Living Desert. As an easily recognizable species of kangaroo rat, the giant kangaroo rat possesses a degree of charisma and is seen as adding aesthetic value to the region.

Comments: See Good et al. (1997) for information on genetic structure of extant populations of D. ingens. See Williams and Kilburn (1991) for a review of the possible relationships between D. ingens and other Dipodomys.