Mammal Species of the World
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- Original description: Merriam, C.H., 1907. Descriptions of ten new kangaroo rats, p. 77. Proceedings of the Biological Society of Washington, 20:75-80.
The range of Dipodomys microps encompasses most of the arid regions of Nevada. It extends west to the Sierra Nevada, east to the Wasatch Mountains of Utah and south to the Colorado River. In southern California distribution is discontinuous, but populations occur as far south as Joshua Tree National Monument. At its northwest corner, the range extends north into southeastern Oregon and east into the Raft River Valley in Idaho.
Biogeographic Regions: nearctic (Native )
- Hayssen, V. 1991. *Dipodomys microps*. Mammalian Species, 389: 1-9.
endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Nearly the entire Great Basin from southwestern Idaho (Raft River Valley, Cassia County; Elmore Desert, Elmore County) and southeastern Oregon through eastern California, Nevada, and western Utah to southern California and northern Arizona; west to the Sierra Nevada, east to the Wasatch Mountains. Generally at moderate elevations but recorded up to 3200 m in Inyo County, California. Discontinuous relict distribution in San Bernardino County, California. Limits of subspecies PREBLEI and IDAHOENSIS in Oregon, CELSUS and LEUCOTIS in Arizona, and CELSUS and OCCIDENTALIS in Nevada are uncertain (Hoffmeister 1986, Hayssen 1991).
D. microps is a medium sized, 5-toed kangaroo rat with a narrow face, small ears and ever-growing cheekteeth. Its incisors are flat on the anterior side and less incurved than other members of the genus. Chisel-toothed kangaroo rats are about 270 mm long and weigh about 55 g. The body without the tail is about 112 mm in length. Tail length adds about 158 mm. Males are slightly larger than females on average. The fur is brown and gray above with a "gunmetal hue." D. microps is white below. The pelage is slightly darker than other Dipodomys species. Not including the feet, the hind leg is twice as long as the foreleg. The hind foot is the same length as the femur. There are 13 subspecies distinguishable by a combination of cranial and bacular measurements or by range.
Average mass: 55 g.
Average length: 270 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Length: 30 cm
Weight: 75 grams
Size in North America
Average: 270 mm
Range: 245-295 mm
Average: 55 g
Range: 40-70 g
The chisel-toothed kangaroo rat is a desert dweller. It is found in mountains at elevations between 1,000 and 3,500 m. Its abundance is primarily associated with two plants: Atriplex confertifolia in desert valleys and Coleogyne ramosissima (deciduous blackbush) in desert uplands. In San Bernardino County, California, D. microps is found in the yucca plant belt. Other dominant plants found in its habitat include Eurotia lanata (winterfat), Kochia americana (kochia), Grayia sponosa (hop sage), Agropyron (wheatgrass), Cercocarpus ledifolius (mountain mahogany), Juniperus (juniper), Artemesia tridentata (sagebrush), Sarcobatus vermiculatus (greasewood) and Larrea tridentata (creosote). In sympatry with D. merriami or D. ordii, D. microps is found in areas of gravel soil more than in areas with fine sand or clay.
Range elevation: 1000 to 3200 m.
Average elevation: 1200 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune
Habitat and Ecology
Nests are found in underground burrows that typically open near the base of shrubs. In Inyo County, California, mating usually occurs from February to mid-March, with births from March to mid-April or sometimes later. Pregnant females occur from April to June in Nevada. Gestation lasts 30-34 days. Females produce a single litter of one to four (most often two), though under exceptionally good conditions a few may produce two litters per year. Juveniles typically do not mature sexually in their season of birth in southeastern California (Kenagy and Bartholomew, 1985).
Chisel-toothed kangaroo rats are basically solitary. Reported average home range size varies from less than one hectare to about five hectare (see Hayssen, 1991). They are most abundant in spring and early summer. They are a major primary consumer and prey item for carnivores. Life span averages just over a year. Diet generally is dominated by leaves (especially of saltbush, from which hyper saline outer layers are removed) in the northern and central parts of the range, by seeds in the south. Will sometimes eat insects and fungi. Climbs saltbush plants to forage for leaves. Caches leaves and/or seeds in burrow. This species is active throughout the year and is not known to aestivate or hibernate. They are nocturnal with limited activity at dawn and dusk.
Comments: Desert valleys dominated by saltbush/shadscale (ATRIPLEX CONFERTIFOLIA) throughout most of range; blackbush (COLEOGYNE RAMOSISSIMA) zone along the southern edge of its range; in southern Nevada, most abundant in COLEOGYNE and GRAYIA/LYCIUM communities; also occurs in other types of shrubby communites. Occurs on rocky slopes in some areas. Rarely has been captured on sand dunes. See Hayssen (1991) for further habitat information. Nests are in underground burrows that typically open near the base of shrubs.
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.
D. microps eats leaves of Coleogyne ramossisima and Atriplex confertifolia primarily and seeds secondarily. Its chisel-shaped incisors are adapted to remove the salty outer parts of the leaves of Atriplex confertifolia (Saltbush). In the spring Atriplex leaves are eaten whole, but as salinity builds up in the outer parts of the leaves in summer and fall, these kangaroo rats use their incisors to access the nutritious and less saline inner parts of the leaves. Avoiding the salty parts of the plants enables D. microps to take advantage of the water content and nutrition in the leaves while maintaining water balance. None of the kangaroo rats needs to drink much, because this genus is able to use the water in their foods.
Seeds become a dominant part of the diet when leaves are unavailable. Granivory is more common in the southern part of the range. D. microps forages above ground at night. During the day, these kangaroo rats engage in coprophagy below ground.
D. microps assimilates 91.3% of its diet. The folivorous diet results in a reduced competition with sympatric congenerics, who specialize more in eating seeds. The unique diet of D. microps is also related to the large cheekpouch capacity of the species. Unlike their smaller-pouched relatives, D. microps has a whopping 4 cubic centimeters per pouch. In spite of the large capacity of their cheek pouches, these kangaroo rats are slower at filling them than are other species of kangaroo rat.
All kangaroo rats apparetnly cache food in their burrows. Cheek pouches help the rats carry food to the burrow.
Plant Foods: leaves; seeds, grains, and nuts
Other Foods: dung
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Folivore , Granivore )
- Vander Wall, S., W. Longland, S. Pyare, J. Veech. 1998. Cheek pouch capacities and loading rates of heteromyid rodents. Oecologica, 113: 21-28.
Comments: Diet generally is dominated by leaves (especially of saltbush, from which hypersaline outer layers are removed) in the northern and central parts of the range, by seeds in the south. Sometimes eats insects and fungi. Climbs saltbush plants to forage for leaves. Caches leaves and/or seeds in burrow.
Because of its food caching behavior, this species likely disperses seeds. It is also a small mammal, and probably forms an important part of the diet of local predators. Because it potentially has as many as 4 sympatric congenerics in some parts of its range, the chisel-toothed kangaroo rat plays a role in regulating congener populations.
Ecosystem Impact: disperses seeds
- Jenkins, S., S. Breck. 1998. Differences in food hoarding among six species of heteromyid rodents. Journal of Mammalogy, 79: 1221-1233.
- Lemen, C., P. Freeeman. 1986. Interference competition in the heteromyid communityin the Great Basin of Nevada, USA. Oikos, 46: 390-396.
- Lemen, C., P. Freeman. 1987. Competition for food and space in a heteromyid community in the Great Basin Desert. Great Basin Naturalist, 47: 1-6.
Feral cats prey on Dipodomys microps. Although reports are lacking, it is likely that this species also falls victim to generalist nocturnal carnivores, such as foxes, coyotes, and owls. Snakes may also enter their borrows and take some animals.
- Hafner, D. 2000b. "Dipodomys microps ssp. leucotis" (On-line). Accessed November 14, 2001 at http://www.redlist.org/search/details.php?species=6679.
This list may not be complete but is based on published studies.
Basically solitary. Reported average home range size varies from less than 1 ha to about 5 ha (see Hayssen 1991). Reported population density: up to about 7/ha in Nevada, to 34/ha in Utah. Most abundant in spring and early summer. A major primary consumer and prey item for carnivores. Life span averages just over a year.
Life History and Behavior
Modes of communication include olfactory and acoustic. Chisel-toothed kangaroo rats sandbathe to spread their scent and use foot drumming, possibly as territorial behavior. Aggressive encounters are also used as a form of communication in this species.
Communication Channels: tactile ; acoustic ; chemical
Other Communication Modes: pheromones ; scent marks ; vibrations
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
Comments: Active throughout the year. Not known to aestivate or hibernate. Nocturnal with limited activity at dawn and dusk.
The average lifespan is 4.9 month, but this, is of course, misleading. Many kangaroo rats die young, and those who make it to adulthood can live a very long time. Although maximum lifespan for D. microps has not been reported, one captive D. ordii lived to be nearly 10 years old!
Status: wild: 4.9 months.
Status: wild: 4.9 months.
- Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: Johns Hopkins University Press.
Males compete for access to females, usually with some aggression. Foot drumming among males may play a part in determining or securing access to females. That males are larger than females in a mammalian species typically is an indication that there is competition between males for females, and that there is some level of polygyny.
Copulation lasts 3-6 minutes. A copulatory plug is employed, indicating that there is some level of sperm competition, and therefore of females mating with multiple males.
Females do not accept copulations outside of their fertile period. Non-receptive females can be aggressive and even kill males attempting to mate with them.
Mating System: polygynandrous (promiscuous)
Most information on the reproduction of these animals comes from studies of captive animals. Female D. microps have an estrous cycle of about 12 days. Sperm production in males occurs from late autumn to early spring. Gestation takes 30-34 days, and average litter size is 2.4 young. Newborns weigh about 4 g and grow to 21 g in 4 weeks. Young appear above ground at the peak of Atriplex growth, when this plant has its highest water content. No information on time of weaning is available.
Little information is available on the timing and length of the breeding season except in the Owens Valley in Inyo County, California, where mating occurs in February and early March, with births occurring in March or early April. Pregnant females have been found from April until June in Nevada, indicating that the breeding season may vary geographically.
In exceptionally good years, females can produce two broods during the year, and the young of the year may reproduce. This means that the young mice may reach sexual maturity by as early as two months of age.
Breeding interval: Female D. microps breed once annually, on average. In unusually good conditions, females produce two litters in a year.
Breeding season: varies geographically; sometime between late winter and early summer.
Average number of offspring: 2.4.
Range gestation period: 30 to 34 days.
Range age at sexual or reproductive maturity (female): 2 (low) months.
Range age at sexual or reproductive maturity (male): 2 (low) months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
As in all mammals, the young receive parental care from the mother. The young are born poorly developed and weighing only a few grams. Females nurse their young in a burrow until the young are ready to disperse.
Parental Investment: altricial ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
- Hayssen, V. 1991. *Dipodomys microps*. Mammalian Species, 389: 1-9.
In Inyo County, California, mating usually occurs from February to mid-March, with births from March to mid-April or sometimes later. Pregnant females occur from April to June in Nevada. Gestation lasts 30-34 days. Single litter of 1-4 (most often 2), though under exceptionally good conditions a few may produce 2 litters/year. Juveniles typically do not mature sexually in season of birth in southeastern California (Kenagy and Bartholomew 1985).
Molecular Biology and Genetics
Barcode data: Dipodomys microps
Below is a 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 and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Dipodomys microps
Public Records: 2
Specimens with Barcodes: 3
Species With Barcodes: 1
Two subspecies are listed by the IUCN. Subspecies Dipodomys m. alfredi, the Gunnison Island kangaroo rat is redlisted as data deficient (DD). Gunnison Island is only 1 square kilometer and is located in the Great Salt Lake in Utah. Further demographic information is needed to make a determination as to its status. Subspecies D. m. leucotis, Houserock Valley kangaroo rat, is redlisted as Vulnerable due to limited range and potential habitat degradation through grazing and presence of feral cats. This subspecies occurs in Marble Canyon in Cocino County, northern Arizona.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
- Hafner, D. 2000a. "Dipodomys microps ssp. alfredi" (On-line). Accessed November 14, 2001 at http://www.redlist.org/search/details.php?species=6697.
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Relevance to Humans and Ecosystems
There are no reported negative impacts of this species on humans. However, it is likely that those animals occurring near agricultural areas could present a danger to crops, as has been reported for other species in this genus.
These animals are used in research.
Positive Impacts: research and education
Chisel-toothed kangaroo rat
It is endemic to the United States (found in Nevada, Utah, California, Oregon, and parts of Arizona and Idaho). Their tail is 6.5 inches(136 mm) long, over two inches longer than the rest of their body, which is usually 4.25 inches. There are 13 sub-species.  Saltbush leaves are a major dietary component, requiring specialized physiology to eliminate the salt while retaining water. Their usual habitat is desert shrub.
- Linzey, A.V. & NatureServe (Hammerson, G.) (2008). Dipodomys microps. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 13 January 2009.
- Patton, J. L. (2005). "Family Heteromyidae". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. pp. 846–847. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Reid, Fiona A. (2006). Mammals of North America. ISBN 0-395-93596-2.
- Reid, Fiona A. (2006). Mammals of North America. ISBN 0-395-93596-2.
- Wilson, Don E. (ed.). The Smithsonian Book of North American Mammals. Smithsonian Institution Press. ISBN 1-56098-845-2.
- Mares, Michael A. (1 November 2003), Desert dreams: seeking the secret mammals of the salt pans - Naturalist at Large, Natural History
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Names and Taxonomy
Comments: See Patton (in Wilson and Reeder 2005) for a lst of currently recognized subspecies, based on Williams et al. (1993).