Species accounts

San Joaquin pocket mouse

Perognathus inornatus

SUBFAMILY

Perognathinae

TAXONOMY

Perognathus inornatus Merriam, 1989, Fresno County, California, United States.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

Total length 5-6.3 in (128-160 mm); weight 0.22-0.39 oz (7-12 g); soft pelage with upperparts yellowish.

DISTRIBUTION

Found in west-central California. HABITAT

Lives in arid annual grasslands, desert scrub, fine soils. BEHAVIOR

Sandbathes by alternating sides and rubbing ventrum.

FEEDING ECOLOGY AND DIET

Eats seeds of grasses, shrubs, and forbs.

REPRODUCTIVE BIOLOGY

Breeds from spring to summer; has two litters of four to six young.

San Joaquin Pocket Mouse

I Liomys salvini I Chaetodipus hispidus I Perognathus inornatus

CONSERVATION STATUS

U.S. Fish and Wildlife Service, Department of the Interior (USDI) species of special concern. Two subspecies are Lower Risk/Near Threatened.

SIGNIFICANCE TO HUMANS Disperses seeds. ♦

Hispid pocket mouse

Chaetodipus hispidus

SUBFAMILY

Perognathinae

TAXONOMY

Perognathus hispidus (Baird, 1858), Tamaulipas, Mexico.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Length 7.8-8.8 in (198-223 mm); weight 0.97-1.5 oz (30-47 g); hair is coarse but not spiny, tail is not crested and only slightly longer than body. Olive-buff upper parts lined with black, lower parts are white.

DISTRIBUTION

North Dakota south through Great Plains and Texas to central Mexico, northwest to southeastern Arizona.

HABITAT

Lives in prairie and cultivated areas.

BEHAVIOR

Active all year.

FEEDING ECOLOGY AND DIET

Eats a variety of seeds, green vegetation, and insects.

REPRODUCTIVE BIOLOGY

Females have two or more litters annually from spring to late summer consisting of two to nine young.

CONSERVATION STATUS

Not listed by the IUCN, but a species of concern in Montana and Wyoming.

SIGNIFICANCE TO HUMANS None known. ♦

Salvin's spiny pocket mouse

Liomys salvini

SUBFAMILY

Heteromyinae

TAXONOMY

Heteromys salvini (Thomas, 1983), Guatemala.

OTHER COMMON NAMES Spanish: Raton de monte.

Physical characteristics

Total length 8.3-11 in (210-280 mm); weight female 1.2-1.6 oz (35-45g), male 1.6-2.6 oz (45-75 g). Pelage is hispid consisting of stiff spines and soft hairs. Mixed dark brown hairs above, under parts buffy to white.

DISTRIBUTION

Pacific coastal lowlands of Oaxaca, Mexico to Costa Rica in Central America.

HABITAT

Lives in dry tropical forest. BEHAVIOR

Hoards seeds in burrow; reproductive males move greater distances than females in breeding season. Less tolerant of con-specifics than Heteromys.

FEEDING ECOLOGY AND DIET

Prefers seeds of woody plants in dry forest and insects.

REPRODUCTIVE BIOLOGY

Limited to dry and early rainy season in Costa Rica with an average of 1.8 litters/year with 3.8 pups/litter.

CONSERVATION STATUS

Not listed by the IUCN.

SIGNIFICANCE TO HUMANS

Disperses seeds in its habitat. ♦

Desmarest's spiny pocket mouse

Heteromys desmarestianus

SUBFAMILY

Heteromyinae

TAXONOMY

Heteromys desmarestianus Gray, 1868, Guatemala.

OTHER COMMON NAMES None known.

Physical characteristics

Total length 11.9 in (302 mm); weight 2.4 oz (74 g). Pelage is dark gray to black with white underside.

DISTRIBUTION

Southern Mexico to northwestern Colombia. HABITAT

Lowland tropical forest. BEHAVIOR

Seasonal differences in home ranges; males move greater distances than females; may be social as they tolerate conspecifics in the laboratory.

FEEDING ECOLOGY AND DIET

Feeds on seeds, green leaves, succulent plants.

REPRODUCTIVE BIOLOGY

Breeds year round with seasonal rains; three in litter.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Disperses seeds in tropical forests. ♦

Pale kangaroo mouse

Microdipodops pallidus

SUBFAMILY

Dipodomyinae

TAXONOMY

Microdipodops pallidus Merriam, 1901, Mountain Well, Nevada, United States.

OTHER COMMON NAMES None known.

Physical characteristics

Total length 5.9-6.8 in (150-173 mm); weight 0.33-0.54 (10.3-16.8 g). Small, bipedal rodent with dorsal surface lightly colored and white on ventrum.

DISTRIBUTION

Restricted to central Nevada and small part of eastern California. HABITAT

Open areas of wind-blown sand. BEHAVIOR

Nocturnal and solitary; bipedal locomotion.

FEEDING ECOLOGY AND DIET

Eats seeds and insects.

REPRODUCTIVE BIOLOGY

Nothing is known.

CONSERVATION STATUS

Not threatened, though rare in some portions of its range. One subspecies is Vulnerable.

SIGNIFICANCE TO HUMANS None known. ♦

Banner-tailed kangaroo rat

Dipodomys spectabilis

SUBFAMILY

Dipodomyinae

TAXONOMY

Dipodomys spectabilis Merriam, 1890, Cochise County, Arizona, United States.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Total length 12.1-13.2 in (308-336 mm); weight 3.15-4.18 oz (98-130 g). Large, four-toed, with white tip on tail. Upper parts dark buff, lighter underside. Tail buff with dark upper stripe.

DISTRIBUTION

New Mexico, southeastern Arizona, eastern Texas into Mexico. HABITAT

Found in desert scrub, arid grasslands. BEHAVIOR

Both sexes defend territories of large dirt mounds that contain extensive burrows. Territorial ownership is communicated via individual footdrumming signatures that are modified if the animal moves into a new neighborhood.

FEEDING ECOLOGY AND DIET

Larder-hoards seeds in large dirt mounds.

REPRODUCTIVE BIOLOGY

Breeding season can extend from November to May with additional matings in late summer after abundant rainfall. Females have three or more estrous cycles in a season with male competition increasing as the breeding season progresses.

CONSERVATION STATUS

Not listed by the IUCN, but threatened by overgrazing and eradication by ranchers in some parts of range. D. s. baileyi listed as endangered in Arizona.

SIGNIFICANCE TO HUMANS

Mounds provide habitat in arid environments; this kangaroo rat is a keystone species. ♦

Giant kangaroo rat

Dipodomys ingens

SUBFAMILY

Dipodomyinae

TAXONOMY

Dipodomys ingens (Merriam, 1904), San Luis Obispo County, California, United States.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Largest body mass in the family: total length 12.3-13.7 in (312-348 mm), weight 3-6.3 oz (93-195 g). Pelage is tan with white underside.

DISTRIBUTION

Restricted to 2% of its former range in Central California. Largest population is in the Carrizo Plain National Monument.

HABITAT

Arid grasslands.

BEHAVIOR

Defends territory, but tolerates close neighbors and can discriminate familiar neighbors from strangers. Both sexes foot-drums as territorial advertisement and in response to snakes and kit fox predators; males drum during competition for es-trous females. Has longest footroll of any species with up to 300 individual foot thumps in a footroll.

FEEDING ECOLOGY AND DIET

Granivores that store seeds in burrows, sometimes after allowing seed heads to cure in surface caches.

REPRODUCTIVE BIOLOGY

Reproduce from January to May. Females are polyestrus and average three estrous cycles in a breeding season. Gestation ranges from 30-35 days with a postpartum estrus an average of three days after parturition.

CONSERVATION STATUS

Listed as Critically Endangered by the IUCN. Also a state and federal endangered species in the United States.

SIGNIFICANCE TO HUMANS Keystone species. ♦

Heermann's kangaroo rat

Dipodomys heermanni

SUBFAMILY

Dipodomyinae

TAXONOMY

Dipodomys heermanni Le Conte, 1853, Calaveras County, California, United States.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

Total length 9.8-12.3 oz (250-313 mm), weight 2.3-2.6 oz (7080 g). A medium-sized kangaroo rat with long silky hair and typical color pattern. Its large, dorsal sebaceous gland secrets throughout the year.

DISTRIBUTION

Central California west of the Sierra Nevada mountains. HABITAT

Occupy discrete burrows in dry grassy plains and partly open gravel covered ground on slopes with sparse chaparral, or costal dune scrub habitat.

Common name /

Physical

Habitat and

Conservation

Scientific name

characteristics

behavior

Distribution

Diet

status

Bailey's pocket mouse

Large, with gray fur washed with yellow

Lower Sonoran desert

Southern California

Granivore, detoxifies

Not listed by

Chaetodipus baileyi

and long bicolored tail; sexually

grasslands and transition

across southern

jojoba seeds.

IUCN

dimorphic: total length males 8-9.5 in

zones; sandy soil and rocky

Arizona to extreme

(20.6-24 cm), weight 0.88-1.3 oz

slopes.

southwestern New

(25-38 g); females 6.7-9 in (17-22.8

Mexico, south along

cm), weight 0.8-1.3 oz (24-37 g).

western Mexico and

Baja Peninsula.

Olive-backed pocket mouse

Small to medium sized pocket mouse

Resident of grasslands and

Great Plains from

Weed and grass seeds,

Not listed by

Perognathus fasciatus

with olive-colored back and yellow lateral

desert scrub. Stores food in

southern Canada south

some insects.

IUCN, but

stripe; total length 5-6 in (12.5-14.2 cm),

underground burrows.

to Colorado, United

species of

weight 0.28-0.49 oz (8-14 g).

States.

concern in

Nebraska,

United States

Silky pocket mouse

Very small pocket mouse with total length

Grassy and shrubby habitats.

Great Plains south into

Seeds.

Not listed by

Perognathus flavus

4-5 in (10-13 cm) and weighing 0.17-

Mexico.

IUCN, but

0.35 oz (5-10 g).

species of

concern in

Wyoming, United

States

Spiny pocket mouse

Hispid colorations with pronounced rump

Arid, rocky habitats.

Occurs in narrow strip

Seeds.

Not listed by

Chaetodipus spinatus

spines. Total length 3.5-5 in (8.9-

between southern

IUCN

12.8 cm), weight 0.45-0.63 oz (13-18 g).

Nevada, United States,

adjacent to and west of

Colorado River and in

southern California into

tip of Baja, Mexico.

Mexican spiny pocket mouse

Grayish brown with white underside and

Dense brushy areas.

Mexican Plateau and

Seeds.

Not listed by

Liomys irroratus

stiff spiny hairs mixed with soft slender

adjacent areas extend-

IUCN

hairs on back. Males total length 8.5-

ing north into southern

10.5 in (21.6-26.2 cm), weight 1.4-2.1

Texas, United States.

oz (40-60 g); females total length 4-5 in

(10.2-13.1 cm), weight 1.2-1.8 oz

(35-50 g).

Nelson's spiny pocket mouse

Large gray spiny pocket mouse with soft

Lives in moist habitats in

Northern Central

Primarily granivorious.

Critically

Heteromys nelsoni

bristles instead of spines. Total length

cloud forest.

America from southern

Endangered

13-14 in (32.8-35.6 cm), weight 2.1-

Chiapas, Mexico, to

3.9 oz (60-110 g).

southwest Guatemala.

[continued]

Territorial around burrows but tolerate conspecifics once socialized. Footdrumming communicates social status.

FEEDING ECOLOGY AND DIET

Seeds and green vegetation are main foods.

REPRODUCTIVE BIOLOGY

Females enter estrus every 14-17 days and remain in estrus for a few hours. Breeding is concentrated from February to August with a peak in April. Gestation is 30-31 days and litter size ranges from two to four young.

CONSERVATION STATUS

One subspecies (berkeleyensis) is already extinct and another, morroensis has been on the USDI and State of California endangered species lists since in 1971 and is listed as Critically Endangered by the IUCN. The last official estimate of population size in 1995 on the remaining 37 acres (15 ha) of occupied habitat was fewer than 50 individuals.

SIGNIFICANCE TO HUMANS

Could be a keystone species in some areas. ♦

Common name /

Physical

Habitat and

Conservation

Scientific name/

characteristics

behavior

Distribution

Diet

status

Dark kangaroo mouse

Small, bipedal rodent with dark colored

Fine gravelly soils in sage-

Upper Sonoran sage

Seeds and some Insects.

Not listed by

Microdipodops megacephalus

hair, large hind feet, and long tail. Total

brush desert. Constructs

brush desert In Oregon,

IUCN

length 5.4-7 in (13.8-17.7 cm), weight

elaborate nests.

Utah, California, and

0.35-0.6 oz (10-17 g).

Nevada, United States.

Chisel-toothed kangaroo rat

Medium-sized, gray rodent with special

Occupies desert valleys

Nevada, United States,

Primarily folivorous and

Not listed by

Dipodomys microps

flattened lower incisors. Total length is

dominated by saltbush in the

and parts of adjacent

secondarily granivorous.

IUCN

9.5-11.6 in (24.5-29.5 cm), weight

Great Basin. Removes outer

states.

1.4-2.5 oz (40-70 g).

tissues from leaves of

saltbush and consumes

inner layers. Sandbathes to

maintain pelage and for

communication.

Elephant-eared kangaroo rat

Large-sized, large-eared kangaroo rat

Chaparral-covered slopes.

Very restricted in range

Primarily granivorous.

Not listed by

Dipodomys elephantinus

with long tail and tuft on end. Has five

to San Benito and

IUCN

toes and is moderately dark in color.

Monterrey counties in

Total length is 12-13.3 in (30.5-33.6 cm)

California, United States

weight 2.8-3.2 oz (79-91 g).

Nelson's kangaroo rat

Large bipedal rodent with soft, pale

Occupy grassland plains.

Occurs in Chihuahuan

Windblown seeds.

Not listed by

Dipodomys nelsoni

brownish fur. Total length 12-12.5 in

Like the banner-tailed

Desert in Chihuahua-

IUCN

(31.2-31.9 cm), weight 3-3.3 oz

kangaroo rats, D. spectabilis,

Zacatecas Biotic

(84-93 g).

they construct burrows of

Provice of north-

large, dome-shaped mounds.

central Mexico.

Ord's kangaroo rat

Small to medium-sized kangaroo rat with

Found in various habitats of

Extensive range from

Granivore that eats

Not listed by

Dipodomys ordii

relatively short tail that has a dark tail

sandy soils, semi-arid and

southern Alberta and

seeds of grasses and

IUCN

stripe broader than the white one and a

mixed grasslands, and

Saskatchewan, Canada,

forbes and green

ventral stripe that tapers to a point at end.

scrublands.

central Oregon, and

vegetation.

Total length 8-14 in (20.8-36.5 cm),

eastern California to

weight 1.7-3.4 oz (50-96 g).

central Kansas and

Oklahoma, United

States.

San Joaquin Valley

Small, four-toed species with yellowish

Inhabits grassland and

San Joaquin Valley,

Seeds and vegetation.

Lower Risk/Near

kangaroo rat

brown back and white ventrum. Total

alkaline plains sparsely

California, United

Threatened; two

Dipodomys nitratoides

length 4.7-7 in (12-18.2 cm), weight

covered with grass and

States.

subspecies are

1.2-1.9 oz (33-54 g).

shrubs. Males and females

Critically

establish contact before

Endangered

copulation.

Stephen's kangaroo rat

Medium-sized five-toed kangaroo rat.

Found in sparse grasslands

Limited to three

Granivore.

Lower Risk/

Dipodomys stephensi

and coast sage-scrub

counties in southern

Conservation

habitats.

California, United States

Dependent

Riverside, San

Bernardino, and San

Diego.

Texas kangaroo rat

Medium-sized kangaroo rat with long,

Lives in scattered mesquite

Historically in nine

Grass seed and

Vulnerable

Dipodomys elator

thick tail with white tip on end. Total

shrubs with open areas of

counties in north-central cultivated plants.

length 10-13.5 in (26-34.5 cm), weight

short grass. They maintain

Texas, United States,

2.3-3.2 oz (65-90 g).

open runways between

and one in adjacent

burrows and mesquite

Oklahoma, but now may

shrubs and use visible

inhabit only three Texas

dust-bathing areas.

counties.

Books

Brown, J. H., and B. A. Harney. "Population and Community Ecology of Heteromyid Rodents in Temperate Habitats." In Biology of the Heteromyidae, edited by Hugh H. Genoways and James H. Brown. Special Publication No. 10. Lawrence, KS: The American Society of Mammalogists, 1993.

Corbet, G. B., and J. E. Hill. A World List of Mammalian Species. Oxford: Oxford University Press, 1991.

Eisenberg, John F. "The Behavior Patterns of Desert

Rodents." In Rodents in a Desert Environment, edited by I. Praakash and P. K. Ghosh. The Hague: Dr. W. Junk. 1975.

Hafner, John C. "Macroevolutionary Diversification in Heteromyid Rodents: Heterochrony and Adaptation in Phylogeny." In Biology of the Heteromyidae, edited by Hugh H. Genoways and James H. Brown. Special Publication No. 10. Lawrence, KS: The American Society of Mammalogists, 1993.

Kays, R. W., and D. E. Wilson. Mammals of North America. Princeton: Princeton University Press, 2002.

Nowak, Robert M. Walker Mammals of the World. Baltimore: Johns Hopkins University Press, 1999.

Sanchez-Cordero, V., and T. H. Fleming. "Ecology of Tropical Heteromyids." In Biology of the Heteromyidae, edited by Hugh H. Genoways and James H. Brown. Special Publication No. 10. Lawrence, KS: The American Society of Mammalogists: 1993.

Schmidly, D.J., K. T. Walkins, and J. N. Derr. "Biogeography." In Biology of the Heteromyidae, edited by Hugh H. Genoways and James H. Brown. Special Publication No. 10. Lawrence, KS: The American Society of Mammalogists: 1993.

Periodicals

Eisenberg, John F. "The Behavior of Heteromyid Rodents." University of California Publications in Zoology 69 (1963): 1-100.

Goldingay, R. L., P. A. Kelly, and D. F. Williams. "The Kangaroo Rats of California: Endemism and Conservation of Keystone Species." Pacific Conservation Biology 3 (1997): 47-60.

Kenagy, G. J. "Adaptations for Leaf Eating in the Great Basin Kangaroo Rat, Dipodomys microps." Oecologia 12 (1973): 383-412.

Perri, L. M., and J. A. Randall. "Behavioral Mechanisms of Coexistence in Sympatric Species of Desert Rodents, Dipodomys ordii and D. merriami." Journal of Mammalogy 80 (1999): 1297-1310.

Randall, Jan A. "Behavioural Adaptations of Desert Animals (Heteromyidae)." Animal Behaviour 45 (1993): 263-287.

-. "Convergences and Divergences in Social

Organization and Communication in Desert. Rodents." Australian Journal of Zoology 42 (1994): 405-433.

-. "Evolution and Function of Drumming as

Communication in Mammals." American Zoologist 41 (2001): 91-104.

-. "Mating Strategies of a Nocturnal Desert Rodent

(Dipodomys spectabilis)." Behavioral Ecology and Sociobiology 28 (1991): 215-220.

Randall, J. A., and M. Matocq. "Why Do Kangaroo Rats Footdrum in the Presence of Snakes?" Behavioral Ecology 8 (1997): 404-413.

Randall, J. A., E. R. Hekkala, L. D. Cooper, and J. Barfield. "Familiarity and Flexible Mating Strategies of a Solitary Rodent, Dipodomys ingens." Animal Behaviour 64 (2002): 11-21.

Organizations

The American Society of Mammalogists.

Web site: <http://www.mammalsociety.org/>

IUCN—The World Conservation Union. Rue Mauverney 28, Gland, 1196 Switzerland. Phone: +41 (22) 999 0000. Fax: +41 (22) 999 0002. E-mail: [email protected] Web site: <http://www.iucn.org>

United States Fish and Wildlife Service. Web site: <http://www.fws.gov/>

Jan A. Randall, PhD

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