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Dipodomys californicusCalifornia kangaroo rat

By Cara S. Gore

Geographic Range

Dipodomys californicus is found in California as far south as San Francisco Bay and north to south-central Oregon. This species occurs on the floor of the Sacramento Valley and below 400 m in the foothills of the Sierra Nevada and Cascade mountain ranges. (Grinnell, 1922)

Habitat

Dipodomys californicus inhabits open grasslands or open areas in mixed chaparral. It prefers areas that get less than 50 cm of precipitation per year, and requires well drained soils that are suitable for burrowing. This species requires fine sand or soil for dust bathing. It is found from elevations of 60 to 400 m (Brylski, 2001; Kelt, 1988)

  • Range elevation
    60 to 400 m
    196.85 to 1312.34 ft

Physical Description

Dipodomys californicus ranges from 260 to 340 mm in total length. The tail is longer than the body at 152 to 217 mm in length. Like all kangaroo rats, these animals have large hind feet and small forefeet. Each of their feet has four toes. They have large eyes and ears and silky fur. They are dark colored on top, ranging from cinnamon to nearly black, and are very light underneath. Their long, well furred tail is tufted with white at the tip. They have external cheekpouches on each side of their face. The dental formula of D. californicus is 1/1 0/0 1/1 3/3. Males and females are similar although males tend to be slightly larger. The head-body length of these animals ranges from 260 to 340 mm. In general, D. californicus increase in size towards northern California and Oregon. The juveniles can be differentiated from the adults only by tooth wear and skull characteristics. The species can be differentiated from similar species such as Dipodomys deserti and Dipodomys merriami by their coloration and size. Dipodomys deserti is larger, D. merriami is smaller, and both species are lighter in color. Dipodomys californicus also has a broader face than either of these two species. (Kelt, 1988)

  • Range length
    260 to 340 mm
    10.24 to 13.39 in

Reproduction

The mating system of these animals has not been described in the literature.

There isn't much data available on the specific reproductive behavior of D. californicus. Breeding may occur year-round if the conditions are favorable, but is most likely to occur between February and September, peaking from February to April. A female may produce as many as 3 litters per year. Their estrous cycles may be effected by food availability. There are 2 to 4 altricial young per litter.

Within the genus Dipodomys, gestation lasts 29 to 36 days. Birth weights vary between 3 and 6 g. The time until weaning apparently varies, as Dipodomys nitratoides weans its young between 21 and 24 days, and Dipodomys panamintinus weans its young between 27 and 29 days. However, the young of Dipodomys ordii remain in their natal nest for 4 to 5 weeks, indicating that the time of weaning may be later than in the other species mentioned. Individuals of other species in the genus Dipodomys have been known to reach sexual maturity as early as 2 months of age.

(Grinnell, 1922; Kelt ,1988; Nowak ,1995; Nowak, 1999)

  • Breeding season
    February through September
  • Range number of offspring
    2 to 4

Parental care for the altricial young is solely a female occupation, as these mice are strictly solitary outside of the interaction between mother and offspring. Females nurse the young in a protected burrow until they are ready to disperse. (Nowak, 1999)

Lifespan/Longevity

No data were found relating specifically to D. californicus. An individual of D. ordii is known to have lived in captivity for 9 years and 10 months. (Nowak, 1995; Nowak, 1999)

Behavior

Kangaroo rats active mainly at night. They are solitary and fiercely territorial. They come together briefly for mating and their home territories may overlap some, but they mostly avoid contact with conspecifics. (Eisenberg, 1963)

Communication and Perception

Dipodomys californicus is not very vocal. Individuals of this species use scent marks and foot drumming to communicate with conspecifics. They mark their territory with scent and if they detect another kangaroo rat nearby, they hit their hind feet on the ground to create vibrations that signal to the other kangaroo rat to go away. No one is exactly sure how much is communicated by footdrumming, but some species of kangaroo rats have very complex footdrumming patterns. (Shier et al., 1999)

Food Habits

Dipodomys californicus eats mostly seeds and berries. It also consumes some tubers, green vegetation, and may eat a few insects. Individuals of this species make small food caches by burying food in an area near their burrow. Dipodomys californicus seems to prefer manzanita berries in the fall and green vegetation in the spring. They don't need a source a fesh water as they get water from their diet and through metabolic processes. This is widely thought to be an adaptation to life in an arid climate (Kelt, 1988; Nowak, 1995).

Foods eaten include: manzanita seeds and berries, Ceanothus seeds, rabbitbrush, lupines, bur-clover, insects, wild oats, small tubers and green vegetation.

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts
  • fruit

Predation

Dipodomys californicus is preyed upon chiefly by stealthy hunters such as foxes and owls, so the large auditory bullae found in this species may be an adaptation to improve hearing and thus ability to detect predators. The very long hind legs and feet are an adaptation to enable kangaroo rats to escape quickly by ricocheting-type locomotion, and are found in all members of the genus. (Eisenberg, 1963)

Ecosystem Roles

Although this species is preyed upon by by several natural predators, it probably does not constitute a significant portion of their diets. Kangaroo rats in general are solitary and do not occur in high concentrations. They do aid in the dispersal of seeds as they don't eat every seed they stash. They are hosts to several species of flea and one species of tick. (Kelt, 1988)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

This species has no obvious benefit to humans.

Economic Importance for Humans: Negative

D. californicus may have a slight impact on grain crops. (Eisenberg, 1963)

  • Negative Impacts
  • crop pest

Conservation Status

Kangaroo rats have no special conservation status.

Other Comments

Dipodomys californicus was originally thought to be a subspecies of Dipodomys heermanni. Biochemical and other data now support the classification of D. californicus as a separate species. (Patton et al., 1976)

Contributors

Cara S. Gore (author), Humboldt State University, Brian Arbogast (editor), Humboldt State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

vibrations

movements of a hard surface that are produced by animals as signals to others

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Brylski, P. "California Wildlife Habitat Relationships System" (On-line). Accessed November 2, 2001 at http://www.dgf.ca.gov/whdab/cwhr/M105.html.

Eisenberg, J. 1963. The Behavior of Heteromyid Rodents. Berkeley, CA: University of California Press.

Grinnell, J. 1922. A Geographical Study of the Kangaroo Rats of California. Pp. 2-110 in J Grinnell, C Kofoid, eds. University of California Publications in Zoology V.24. Berkeley, CA: University of California Press.

Kelt, . 1988. *Dipodomys californicus*. Mammalian Species, 324: 1-4.

MacArthur, H., J. Patton, S. Yang. 1976. Systematic Relationships of the Four Toed Populations of *Dipodomys heermanni*. Journal of Mammalogy, 57: 159-163.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.

Nowak, R. 1995. "Walker's Mammals of the World Online" (On-line). Accessed October 12, 2001 at http://www.press.jhu.edu/books/walker/rodentia/heteromyidae.dipodomys.html.

Shier, D., S. Yoerg. 1999. What Footdrumming Signals in Kangaroo Rats. Journal of Comparative Psychology, 113 No.1: 66-73.

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