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Dipodomys venustusnarrow-faced kangaroo rat

By Scott Remke

Geographic Range

Dipodomys venustus is found in the coastal mountain range of central California, from the tip of the San Francisco peninsula to slightly north of Santa Barbara. (Best, 1992; Hawbecker, 1940)

Habitat

This kangaroo rat is a burrowing rodent that usually dwells in soft, sandy, well-drained soil, where the associated vegetation generally consists of chaparral or chaparral interspersed with oak or digger pine.

The average rainfall in this range is about 75 cm, with the majority of it falling in the winter (November-March). The dry months are offset by a consistently present fog bank, which helps maintain moisture levels in the region.

D. venustus is found at elevations from sea level to 1,770 m. It typically inhabits slopes. (Best, 1992)

  • Range elevation
    0 to 1770 m
    0.00 to 5807.09 ft

Physical Description

D. venustus is a darkly colored, five-toed rodent that is medium-sized for its genus. By human standards, it is pretty cute, having large eyes set in a narrow face. The nose and ears are black. There are yellowish hairs on the back, which are more prominent on the sides, giving the flanks a lighter coloration. The cheeks and the ventrum are light colored.

Males weigh approximately 83 g (range 70 to 97 g) with females averaging about 82 g (range 68 to 96 g). There is sexual dimorphism in length, with males being longer (about 318.2 mm for males, compared with 313.5 mm for females), and having longer hind feet. The basal length of cranium, greatest length of cranium, maxillary arch spread, width of maxillary arch, greatest depth of cranium, greatest width of cranium, and zygomatic width are also larger in the males. (Best, 1992; Wilson and Ruff, 1999)

  • Sexual Dimorphism
  • male larger
  • Range mass
    68 to 97 g
    2.40 to 3.42 oz
  • Average mass
    82-83 g
    oz
  • Range length
    293 to 330 mm
    11.54 to 12.99 in
  • Average length
    313.5-318.2 mm
    in

Reproduction

The mating system of this species has not been described. However, within the genus Dipodomys, there is a tendency for males and females to come together only for mating purposes. Males and females inhabit separate burrows. In some species, males may attract females using foot drumming. (Nowak, 1999)

Female D. venustus have one to two litters per year with two to four young per litter. Data on seasonality of breeding are limited, although one nest was excavated in late May in which a mostly helpless baby was found.

Although the gestation period of this species has not been reported, within the genus Dipodomys gestations generally range from 29-36 days. The average female cycle is about 12 days in length. Birth weights range from 3-6 g. Young typically remain n the nest for 4 or 5 weeks, and can reach reproductive maturity as young as 2 months of age. (Best, 1992; Nowak, 1999)

  • Breeding interval
    These kangaroo rats usually produce one litter per year. Under good conditions, a female may produce two litters per year.
  • Breeding season
    The breeding season has not been officially described, but would appear to occur in the spring months.
  • Range number of offspring
    2 to 4
  • Range gestation period
    29 to 36 days
  • Range weaning age
    4 to 5 weeks
  • Range time to independence
    4 to 5 weeks
  • Range age at sexual or reproductive maturity (female)
    2 (low) months
  • Range age at sexual or reproductive maturity (male)
    2 (low) months

As in all mammals, the female provides extensive parental care, nursing the young until they are able to eat solid foods. Mothers care for their young in a nest within a burrow. Young are born helpless, so the nest environment is an important source of protection for them while they are young.

No male parental care has been reported for these animals, and the males and females live separately. (Best, 1992; Nowak, 1999)

  • Parental Investment
  • altricial
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

Information on the lifespan of this species was not available in the literature. However, one member of the same genus, D. ordii lived for nearly 10 years in captivity. (Nowak, 1999)

Behavior

D. venustus does not venture far from its burrow. Little else has been observed. Members of the genus tend to be solitary and territorial, with only one adult occupying a single burrow.

Unlike most members of the genus Dipodomys, D. venustus is water dependent. These animals become emaciated and will die if they do not have access to water, or have to subsist on dry seeds. This is apparently a primative characteristic for the genus. (Hawbecker, 1940; Nowak, 1999; Hawbecker, 1940; Nowak, 1999)

Home Range

The home range size for these animals is not known.

Communication and Perception

Little is known about the communication of D. venustus. However, within the genus, animals are known communicate with a combination of vocalizations, foot drumming, and scents. Dustbathing is common in some species, and allow animals to both spread their scents and detect the scents of others. (Best, 1992; Nowak, 1999)

Food Habits

Dipodomys venustus feeds primarily on the ripe seeds of annual plants, with the achene (a small, dry, one-seeded fruit) of H. grandiflora (telegraph weed) being a preferred food. D. venustus makes one or several caches of seeds in its primary burrow, and makes many storage caches within close proximity of the entrance to its burrow. This species consumes very little free water, getting the vast majority from food. However, unlike other members of the genus, it must have some access to free water. (Best, 1992; Church, 1969; Hawbecker, 1940)

  • Plant Foods
  • seeds, grains, and nuts

Predation

Information is limited regarding the predators of D. venustus. D. venustus bones are not found in the pellets of associated barn owls, suggesting D. venustus is not part of the owl's diet. However, it is likely that these animals fall prey to many of the standard predators of rodents in the region, including hawks, falcons, owls, coyotes, fox, bobcats, and house cats. (Hawbecker, 1940)

Ecosystem Roles

D. venustus contributes in dispersing seeds. It is probably also important to the diets of some predators. (Hawbecker, 1940)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

none

Economic Importance for Humans: Negative

D. venustus minimally consumes the seeds of cultivated crops. (Hawbecker, 1940)

  • Negative Impacts
  • crop pest

Conservation Status

D. venustus is not threatened or endangered

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Scott Remke (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.

fertilization

union of egg and spermatozoan

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

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

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

scent marks

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

seasonal breeding

breeding is confined to a particular season

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).

vibrations

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

visual

uses sight to communicate

viviparous

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

References

Best, 1992. *Dipodomys venustus*. Mammalian Species, 403: 1-4.

Church, 1969. Evaporative Water Loss and Gross effects of Water Privation in the Kangaroo Rat, *Dipodomys venustus*. Journal of Mammalogy, 50: 514-523.

Hawbecker, 1940. The Burrowing and Feeding Habits of *Dipodomys Venustus*. Journal of Mammalogy, 21: 388-396.

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

Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals. Washington and London: Smithsonian Institution Press.

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