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Caloprymnus campestrisdesert rat kangaroo

By Lindsay DuVall

Geographic Range

Caloprymnus campestris is thought to occupy a relatively small area in Southern Australia, extending just over the borders of Queensland and Northern Territory. Although not spotted since 1935 (when it was seen in the Lake Eyre region of northern Southern Australia), apparently recent remains of C. campestris have been found in caves of southeastern Western Australia (Lavery, 1985).

Habitat

Caloprymnus campestris lives in an arid, desert region of Australia,including clay pans, sandridges and gibber plains. Cover is sparse and consists of saltbrush, cherropods and Emu bush (Nowak, 1992).

Physical Description

The coloring of the pelage of C. campestris is appropriate for its desert surroundings. A pale, yellowish, ochre on top blends C. campestris with clay soils; while ventral surfaces are lighter. The muzzle of C. campestris is short with large upper lips. Ears are very long and covered with fur. Neck glands have been observed in some specimens. A distinguishing feature of C. campestris is the difference in size between fore and hindlimbs. Forelimbs are quite delicate with bones weighing 1 gram, while hindlimbs are large with bones weighing 12 grams. This difference is related to saltation. Other characteristics related to hopping locomotion include the large difference in limb size, long tail, plantigrade hindfoot, and syndactyly. The 4th toe of the hindfoot is the longest and is extremely strong. Caloprymnus campestris has an anteriorly opening pouch with 4 teats. Dentition is another crucial distinguishing feature. Caloprymnus campestris exhibits diprotodonty. Incisors are large with the 2nd and 3rd incisors smaller and laterally placed. Dental formula is 3/1, 1-0/0, 2/2, 4/4 = 32-34. There's also a blade-like premolar used for cutting, located behind a diastema. Molars are thought to erupt spontaneously, in contrast with other macropodids, in which eruption is sequential (Ganslosser 1988, Myers 1997, Nowak 1991, Strahan 1995).

Reproduction

Caloprymnus campestris females reach sexual maturity at approximately 11 months, while males reach maturity about 2 months later. There is marked sexual dimorphism with females being larger. Females go through estrous at 3 week intervals and can mate throughout the year. Although able to mate all year, Caloprynmus has an irregular breeding season when most mating takes place. Females with pouched joeys have been found between June and December. Young are born very undeveloped, as is typical of marsupials. Gestation is probably around 1-2 months, with a pouch period of 2-3 months. All females were found with only 1 young at a time. Young remain dependent for over 1 month after leaving the pouch and soon after leave permanently. Note: Due to indeterminate status (see Conservation and Biodiversity section), some reproductive characters were determined by comparing C. campestris to the Rufous Rat kangaroos and other "rat" kangaroos, rather than by direct observation (Ganslosser, 1988).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Lifespan/Longevity

Behavior

Caloprymnus campestris is solitary except for young offspring with mothers. It lives in nests built over shallow depressions in the ground. Nests are excavated or found and are crucial in the desert, where there is relatively little brush or foliage to find cover under. The "pits" are lined with grass, which females carry to the nest with their tails. The nest is then covered with twigs. Caloprymnus spends most of the day taking shelter from the desert sun in its simple nest. Oftentimes, C. campestris is found peeking out of the top of the nest to observe its surroundings. Caloprymnus campestris has a distinct method of hopping. Its posture is forward and the 297-399mm tail is extended when it moves at high speeds, . Jumping is restricted to the back legs. Unlike other species, Caloprymnus lands with the right foot in front of the left foot. Caloprymnus campestris can move at full speed for as long as 20km. When moving at low speeds, C. campestris is pentapodal and moves like a rabbit (Strahan, 1995).

Communication and Perception

Food Habits

Caloprymnus campestris is mainly herbivorous but has been found to eat insects such as beetles and weevils. Calprymnus campestris nocturnally feeds on foliage and stems of vegetation. As a desert inhabitant, C. campestris is able to exist without surface water while feeding on green plants (Strahan, 1995).

Economic Importance for Humans: Positive

Australian aborigines used to capture C. campestris, possibly for food. Besides that, C. campestris has no other known economic importance (Lavery, 1985).

Conservation Status

Listed as indeterminate by the IUCN, and endangered by the USDI; C. campestris was last reported in 1935. It may be extinct, or it may be present in very small populations, waiting for conditions such as drought in which to make a comeback. No thorough efforts have been made to determine its status. Possible reasons for its decline and disappearance are the introduction of predators such as the fox and cat; competitors such as the rabbit; and the clearing of land for cattle grazing (Jenkins and Thornback, 1982).

Other Comments

The latin meaning of Caloprymnus is "beautiful rump," probably alluding to its beauty and powerful hind legs. Campestris means "plain, level country," referring to its habitat. Besides being called the desert rat kangaroo, C. campestris is also called the plains rat kangaroo (Strahan, 1995).

Contributors

Lindsay DuVall (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

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.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

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.

sexual

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

tactile

uses touch to communicate

References

Ganslosser, U. 1988. Grizimek's Encyclopedia. McGraw-Hill Publishing, New York. Vol 1. pgs. 35-39.

Jenkins, M. and Thornback, J. 1982. The IUCN Mammal Red Data Book Part 1. IUCN Gland, Suiz. pgs. 33-34.

Lavery. 1985. The Kangaroo Keepers. University of Queensland Press, Queensland. pgs. 46-48.

Myers, P. 1997. Animal Diversity Web. http://www.oit.itd.umich.edu/projects/ADW/

Nowak, R.M. 1991. Walker's Mammals of the World. Johns Hopkins University Press, Baltimore. Vol 1. pgs. 10-12, 90-91.

Strahan, R. 1983. The Australian Museum Complete Book of Australian Mammals. Angus and Robertson Publishers. pgs. 177-178, 192.

Strahan, R. 1995. The Mammals of Australia. Reed Books, Australia. pgs. 296-297.

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