Durrant suggested that D. microps speciated from others in the genus as a result of the formation and subsequent recession of Lake Bonneville which occupied much of the Great Basin in the Pleistocene. D. microps can quickly colonize areas that were recently underwater.
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
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
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
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
Commensal/Parasitic Species:
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 )
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 )
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
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!
Average lifespan
Status: wild: 4.9 months.
Average lifespan
Status: wild: 4.9 months.
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
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.
Known Predators:
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)
The chisel-toothed kangaroo rat (Dipodomys microps) is a species of rodent in the family Heteromyidae.[2]
There are 13 sub-species.[3] Saltbush leaves are a major dietary component, requiring specialized physiology to eliminate the salt while retaining water.[4]
They ranges between 268.4 - 273mm long with their body length from 100 - 116mm and tails being longer than their body ranges between 136 - 190mm.[5] Their hind feet are approximately 40% the length of their body and ranges between 40 - 45mm and the front limbs being much shorter. Males tend to be a bit larger than the females. Their backs can range from a sandy brown, gray-brown to a pale yellow, their bellies are white, and their sides range from yellow to yellow gray.[6] They have "tufted" tails which are brown with white stripes on the sided and the tuft at the end of the tail being dark brown with scattered white hairs. They have large rounded bicolour ears. Their incisors are unique and are used to identify them, they are anteriorly flattened and broad,[7] like chisels, which is where their name comes from.
It is endemic to the United States (found in Nevada, Utah, California, Oregon, and parts of Arizona and Idaho).[6] They inhabit the arid regions with gravelly soils are found at moderate elevations (1000 - 1,500m), though they have been found at elevations of 3,200m above sea level.[5] Their habit is saltbrush, especially Atriplex confertifolia, dominated desert valleys and upland deserts with blackbush and are less common in sand dunes. They create burrows in the ground with multiple entries, usually under the bushes of shrubs. Their usual habitat is desert shrub.[8]
D. microps is a facultative specialist, and the only foliovore in the Dipodomys genus. 60 - 80% of its diet consists of the Atriplex confertifolia's leaves. They do consume some seed and insects, however, this is a small portion of their diet.[9] This desert shrub, Atriplex confertifolia, is adapted to desert life by encrusting its leaf surfaces with a layer of salt crystals, this has a dual purpose, one of which is to reflect incoming solar radiation which help maintain its water homeostasis, and secondly it is a defense against herbivory.[10] D. microps have adapted morphologically, physiologically, and behaviorally to overcome this defense mechanism. They have evolved their lower incisors to become flat, broad, and chisel-shaped, which is a unique to character among the kangaroo rats.[7]
They collect the leaves of the Atriplex shrub and stuff it into their cheek pouch and take it back to their burrows. They have been found to have caches of leaves of up 250g. Their unique incisors are used to scrape/strip the epidermis and the salt layer off of the leaf by repeatedly pulling the leaf downward and perpendicular to its lower incisors. This is then repeated on the other side till the inner tissue, consisting of the parenchyma, vascular tissue, bundle sheath, and the mesophyl, which is then consumed.[11] This part of the leaf has a water content of up to 80% in the spring, and D. microps obtains its water from the leaves. Another adaptation to assist with the consumption is that the upper lip closes off the mouth cavity which reduces the amount of salt entering or falling into the mouth.
{{cite web}}: CS1 maint: archived copy as title (link) The chisel-toothed kangaroo rat (Dipodomys microps) is a species of rodent in the family Heteromyidae.
There are 13 sub-species. Saltbush leaves are a major dietary component, requiring specialized physiology to eliminate the salt while retaining water.
