Notomys fuscusdusky hopping mouse

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Geographic Range

Dusky hopping-mice are distributed from Ooldea in S Australia to past Lake Eyre to SW Queensland. They also currently inhabit the regions of SE Western Australia, S Northern Territory, Southern Australia, N New South Wales, and NE South Australia (southern Strzeleki Desert and the Cobblers Desert). Since 1985, N. fuscus specimens have been collected from Carraweena, Montecollina Bore and Quinyambie Station, and from Pelican Waterhole. (Grizmick 1990, Honaki 1982, Nowak 1991, Rodent Action Plan http://www.anca.gov.au/plants/threaten/sched123.htm)

Habitat

Dusky hopping-mice inhabit sand dunes, grasslands, tree and shrub heaths, and lightly wooded areas. The temperature of their habitat is usually very high with desert-like conditions. N. fuscus also live in sand ridge habitats, which alternate with gibber flats and clay pans, in the Pelican Waterhole area. (Grizmick 1990, Honaki 1982, Nowak 1991, Rodent Action Plan

http://www.anca.gov.au/plants/threaten/sched123.htm)

Physical Description

N. fuscus is characterized by its strong incisor teeth, long tail, large ears, dark eyes, and extremely lengthened and narrow hind feet, which have only four sole pads. Head and body length is 91-177 mm, tail length is 125-225 mm, and weight is about 20-50 grams. Coloration of the upper parts varies from pale sandy brown to yellowish brown to ashy brown or grayish. The underparts of dusky hopping-mice are white. The body covering is fine, close and soft; and long hairs near the tip of the tail give the effect of a brush. Notomys fuscus has a well-developed sebaceous glandular area on the underside of its neck or chest. Females have four mammae. (Grizmick 1990, Honaki 1982, Nowak 1991)

Reproduction

Little is known of the breeding biology of this species in the wild other than that it is an opportunistic breeder. In captivity, its breeding pattern is polyestrous, with no evidence of seasonality, thus it breeds throughout the year. The gestation period is 38-41 days; a postpartum estrus is not common in N. fuscus, but some females enter estrus 14-22 days after giving birth. The estrous cycle lasts about 7-8 days. Dusky hopping-mice rear litters of 1-5 young. Their young weigh about 2-4 grams at birth and open their eyes at 18-28 days. The young cling to the nipples of the mother and are dragged about wherever she goes, and weaning occurs at about 30 days. Both sexes of N. fuscus reach reproductive maturity at 70 days. It was seen that one female N. fuscus produced 9 litters in her lifetime of 26 months. Males are capable of breeding up to the age of 38 months. (Grizmick 1990, Honaki 1982, Nowak 1991)

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

Behavior

The sebaceous glandular area is active in all adult males but is active in females only during pregnancy and lactation. Nowak (1991) suggests that the glands are used for territorial marking and marking of group members, including newborn young. Dusky hopping-mice are saltatorial and normally move awkwardly on all fours or make short hops. If startled, they bound rapidly using only their large hind feet. The mice dig their own burrows, some being of a simple construction but others being complex. The dusky hopping-mouse digs a burrow on the flat top of a dune with a single tunnel about 10 cm in diameter, more than a meter below the surface and up to 5 m long. It is connected to the surface by up to 6 vertical entrance shafts that are dug from below and may end up anywhere on the surface. A nest, consisting of a pad of finely chewed vegetation, is placed in the center of a small alcove off the main shaft, and well-marked pads connect different burrows along the top of the dune. The width of the entrance shafts is critical because the animals move in them by hopping; they brace their backs against the sides with their forefeet between hops. Progress when coming down a shaft is a headlong dive, with the back braced against the wall of the shaft and the forelegs used as a brake. If the entering animal finds that the burrow is blocked with loose sand, it often squeaks several times. This usually attracts other occupants and together, from opposite sides, they rapidly clear the blockage. N. fuscus is commonly found in association with marsupial counterparts and sometimes shares the same tunnel systems. Living in groups of about five individuals in one or two adjacent burrows systems, the Dusky Hopping-mouse spends all its life on the dunes. Being a nocturnal animal, it rests in its burrow during the day, insulated from the hot surface. At night, it forages on the top and sides of a dune, and rarely ventures more than a few meters away. Even in apparently favorable localities, population density is low, with individuals inconspicuously congregated in a loose colony in a small area of a sandhill. Dusky Hopping-mice calls include twittering during animated chases. However, none of the sounds was associated with threats or fighting. (Grizmick 1990, Honaki 1982, Nowak 1991)

Communication and Perception

Food Habits

Notomys fuscus is like other hopping-mice in that it does not drink, but obtains all its water and food requirements from a diet of seeds, berries, leaves, green plants and occasionally insects. (Grizmick 1990, Honaki 1982, Nowak 1991)

Economic Importance for Humans: Positive

Notomys fuscus is used in studies of reproduction because of its rapid breeding cycle. Some studies have included female and male N. fuscus reproductive anatomy and physiology, while other studies have focused on genetic analyses. (Baverstock 1977, Breed 1982, Breed 1985)

Conservation Status

The N. fuscus population is very small, and the species is rarely seen in its known habitats. Recent capture rates suggests the numbers of dusky hopping-mice to be 10 000. The reason for decline in `N. fuscus <<Notomys fuscus>` population size is not known. Notomys fuscus is noted in the lists of ANZECC, and in Appendix II of the Convention in International Trade of Endangered Species (CITES). IUCN considers N. fuscus to be a vulnerable taxon with populations that have been seriously depleted and whose ultimate security is not yet assured. There have been some efforts to assist the recovery of populations of N. fuscus by organizations including the Department of Environment and Natural Resources, SA, and Qld Department of Environment and Heritage and Conservation Commission of the Northern Territory. Their recovery objectives are to undertake a survey to determine the species' current distribution, population size, and habitat requirements. (Refugia for Biological Diversity in Arid and Semi-arid Australia http://kaos.erin.gov.au/life/general_info/biodivser_4/bio119.html

Rodent Action Plan http://www.anca.gov.au/plants/threaten/sched123.htm)

Other Comments

Notomys fuscus means dusky southern mouse. Their large ears are not only for picking up sounds of predators but are also an adaptation for living in extreme heat. The large surface area of the ears allows the blood to flow and cool in the air, thus lowering the body temperature by lowering the temperature of the blood. Key threats are grazing by stock and rabbits. Like other arid zone rodents, N. fuscus is subject to periodic population fluctuations. The numbers in the population follow the seasons of good rainfall and plant growth. In times of sparse rainfall, N. fuscus is well adapted for survival on account of its ability to excrete waste nitrogen in the form of one of the most highly concentrated urines known in a rodent. (Grizmick 1990, Honaki 1982, Nowak 1991, Refugia for Biological Diversity in Arid and Semi-arid Australia http://kaos.erin.gov.au/life/general_info/biodivser_4/bio119.html, Rodent Action Plan http://www.anca.gov.au/plants/threaten/sched123.htm)

Contributors

Kenneth Kim (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

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Baverstock, PR. Polymorphism of the X-Chromosome, Y-Chromosome and Autosomes in the Australian Hopping Mice N. fuscus. Chromosoma.. 1977. 61(3): 243-56.

Breed, WG. Morphological variation in testes and accessory organs of Australian rodents in genera Notomys. Journal of Reproductive Fertility. 1982. 66(2): 607-13

Breed, WG. Morphological variation in female reproductive tract of Australian rodents in genera Notomys. Journal of Reproductive Fertility. 1985. 73(2): 379-84.

Endangered Species in the Arid Zone http://rubens.anu.edu.au/student.projects/rabbits/endangered.html

Grizmick, B. Grizmick's Encyclopedia of Mammals. McGraw-Hill, Inc. New York, NY. 1990. 3: 202-203.

Honaki, J. Mammal Species of the World. Allen Press Inc. Lawrence, KA. 1982. 538.

Nowak, R. Walker's Mammals of the World. John's Hopkins University Press. Baltimore, MD. 1991. 824.

Refugia for Biological Diversity in Arid and Semi-arid Australia http://kaos.erin.gov.au/life/general_info/biodivser_4/bio119.html

Rodent Action Plan http://www.anca.gov.au/plants/threaten/sched123.htm

Wilson, D. E., and D. M. Reeder. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd edition. Smithsonian Institution Press, Washington. 1993. 2: 753.