Total length measures 140-177 mm, head and body length is 66-77 mm, tail length 68-103 mm, and the hind foot is 23-27 mm long. The head is large in proportion to their body size due to the inflation of the tympanic bullae that extends to the upper portion of the cranium. The neck is fairly short. Upper parts are brownish to grayish black. Compared to the similar looking species, M. pallidus, M. megacephalus have basally plumbeous and white-tipped underparts, and the end of the tail is blackish. The distal half of the tail is darker than the proximal. The tail is not crested nor does it end in a tassle; however, it is thick and stores fat. The fat in the tail is used as a source of energy during dormancy.

The pelage is relatively long, silky, and lax. The hind feet are covered with stiff hairs on the sides, which increases the surface of the fine and soft feet. The undersurface of the hind feet are also well furred. The feet functions similar to a sand shoe in a desert.

Kangaroo mice utilize their forelegs more than kangaroo rats when running.

Compared to those of kangaroo rats, the molars of kangaroo mice do not constantly regrow. The base of the zygomatic arch is not enlarged as it is in kangaroo rats.

Several features, including long hind legs, relatively small forelegs, long vibrissae, and enlarged auditory bullae are probably adaptations to the jumping mode of locomotion.

O'Farrell and Blaustein (1974), Nowak (1991), Grizmek (1990).

Average mass: 13.4 g.

Average basal metabolic rate: 0.168 W.

Length: 18 cm

Weight: 17 grams

• Terrestrial

Kangaroo mice are found among bushes growing in soils covered with gravel or on sand dunes. The altitude of the habitat is around 1,190-2,455 meters. Burrows are constructed in soft ground with the entrance near a shrub. Burrows have simple, unbranched tunnels, elaborate nests, and a food storage room. A small territory is maintained near the burrow, but an individual's home ranges may overlap with those of several other individuals. Average home range for males is 6,613 square meters and 3,932 for females. O'Farrell and Blaustein (1974), Nowak (1991)

Terrestrial Biomes: desert or dune

Comments: In loose sands and gravel. Found in Shadscale Scrub, Sagebrush Scrub, and Alkali Sink plant communities in the Upper Sonoran life zone. May occur in sand dunes near margins of range. Underground when inactive.

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.

These kangaroo mice are normally granivorous, although they feed on insects, particularly during summer when their activity reaches its maximum. The shift in diet may be caused by competition for food with pocket mice. Kangaroo mice store food in seed caches found in their burrows. O'Farrell and Blaustein (1974), Nowak (1991), Grizmek (1990).

Comments: Seeds are the primary food source. Also eats some insects. Does not appear to utilize free water. Believed to store food in seed caches within burrow system (O'Farrell and Blaustein 1974).

Predators include owls, foxes, badgers. In west-central Nevada mean yearly circular home range for males was 6613 sq m; for female, 3932 sq m (O'Farrell and Blaustein 1974).

Comments: Activity observed March-October. Peak nocturnal activity occurs in first 2 hours after sunset. Moonlight and ambient temperature influence activity (O'Farrell and Blaustein 1974).

Average lifespan

Status: captivity: 5.4 years.

Females are polyestrous. Pregnant individuals have been found from March to September. The majority of the young are born in May and June. Litter size ranges from 2 to 7 with an average of 3.9. A study done in west-central Nevada showed that the population consisted of 2:1 sex ratio favoring males. A successful reproduction has yet to be recorded in captivity. Maximum longevity (of an individual trapped in the wild) is five years and five months. O'Farrell and Blaustein (1974), Nowak (1991), Grizmek (1990).

Average number of offspring: 4.

Possibly polyestrous (Hall 1946); majority of young are born in May and June. Litter size is 2-7 (average 3.9).

Although not endangered, their number has decreased due to destruction of habitat by modern agriculture and land development. Predators include the kit fox and snakes; however, humans are the biggest threat.

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Comments: Some Microdipodops populations have declined as a result of introduction of weedy grasses and extreme habitat alteration from cultivation (e.g., irrigation of dry sinks) (Hafner et al. 1998). In addition to these human-related habitat changes, apparently natural shifts in vegetative zones have resulted in the replacement of rodent communities including Microdipodops by those including Dipodomys deserti, and vice versa (J. C. Hafner, pers. obs.). Natural and human-related habitat modifications may have amplified effects on the already fragmented, patchy distribution of Microdipodops (Hafner et al. 1998).

Used in laboratory researches for water conservation, renal physiology, and irradiation.   http://netvet.wustl.edu/org/AWIC/misc/uncomsp.htm 

Comments: Hall's (1981) suggestion that subspecies leucotis may warrant specific status was not supported by Hafner and Hafner (1983).