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Dasyuroides byrneikowari

By Alyssa DeRubeis

Geographic Range

Kowaris (Dasyuroides byrnei) inhabit a very small area within southwestern Queensland and northeastern South Australia. They have a patchy distribution near Charlotte Waters, in northern South Australia around Warburton Creek and north of Cooper Creek (south and east of the Simpson Desert), and in western Queensland between the Simpson Desert and Diamantina River, south of Boulia.

Their range falls within the Desert Channels in Queensland and the South Australian Desert Lands Natural Resource Management Regions. Kowaris once occurred in the National Territory, but the last record from this area is from over 100 years ago. ("Kowari Dasyuroides byrnei", 2006; Department of Sustainability, Environment, Water, Population and Communities, 2012)

Habitat

Kowaris reside in a habitat known as gibber plain or patch. The term "gibber" refers to the crushed-up rock bits that litter the ground. Gibber patches are of particular interest to this species along grasslands, sand dunes and islands, mounds, under saltbushes, and river channels. The natural communities within their range are dependent on the Great Artesian Basin's natural groundwater discharge, and kowaris may be dependent on these natural plant communities. ("Animal Info - Kowari", 2005)

Physical Description

Kowaris have a body length of 13.5 to 18 cm and a tail length of 11 to 14 cm for a total of 24.5 to 32 cm total body length. Body mass ranges from 70 to 140 g, with males being larger than females. Their coat is primarily gray in color with hints of brown. This gray fades to white on the belly, with lighter colors on the tops of the feet and tail. Each eye is ringed with a dark narrow band. There is a a distinctive black brush that encompasses the tip and bottom of the tail, which can also be held erect. The unique tail helps distinguish this species from similar looking species in the genus Dasycercus. Kowaris have a pointy pink snout and pink ears. The front feet have five toes while the hind feet have four toes. Males have a primitively structured penis. ("Animal Info - Kowari", 2005; "Kowari (Dasycercus byrnei)", 2006; "Kowari Dasyuroides byrnei", 2006; Woolley, 1988)

  • Sexual Dimorphism
  • male larger
  • Range mass
    70 to 140 g
    2.47 to 4.93 oz
  • Range length
    24.5 to 32 cm
    9.65 to 12.60 in

Reproduction

Kowaris group into heterosexual pairs, though it is unknown if these pairs mate with other individuals. (Aslin, 1980)

Kowaris mate as early as April and as late as December. Larger individuals can tolerate harsher conditions and are therefore able to breed in the winter when smaller individuals cannot. Most females give birth to a litter between May and July and a second litter in November. Females can enter oestrus up to 4 times in a given breeding season in captivity, although not all result in pouch development.

Pairs undergo prolonged mating periods where they may copulate for as long as 3 hours several times over a 1 to 3 day period. Gestation lasts 30 to 36 days, after which females gives birth to a litter of 5 offspring. Once born, the offspring remain in the pouch for about 30 days, but do not become detached until they are 55 days old. At this point, young kowaris either stay in the nest or ride on their mother's back. Offspring stay attached to the mother's teat for 56 days and cannot open their eyes until 74 days of age. At 86 to 95 days of age, young kowaris start play-fighting. By 95 to 110 days, the offspring are able to eat solid food and are thus independent of their mother. Kowaris become sexually mature at 7 to 9 months of age. Some females have been recorded breeding at 3 years of age. Cannibalism by mothers of their own young has been documented in captive colonies and contributes to the low weaning rate. ("Animal Info - Kowari", 2005; "Kowari (Dasycercus byrnei)", 2006; Aslin, 1980; Kortner, 2011)

  • Breeding interval
    Kowaris reproduce twice a year, once during the summer and again in November.
  • Breeding season
    Breeding takes place from April to December, with the majority of mating occuring in between May and July.
  • Range number of offspring
    3 to 7
  • Range gestation period
    30 to 36 days
  • Range weaning age
    95 to 110 days
  • Range age at sexual or reproductive maturity (female)
    7 to 9 months
  • Range age at sexual or reproductive maturity (male)
    7 to 9 months

Female kowaris build a nest where their offspring can stay sheltered after they leave the pouch. Mothers provide milk and a mode of transportion for their offspring until they are completely independent. Male kowaris do not seem to assist females in raising offspring. ("Kowari Dasyuroides byrnei", 2006)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The lifespan of kowaris is currently unknown, though one captive individual lived 6 years and 4 months. ("Animal Info - Kowari", 2005)

  • Range lifespan
    Status: captivity
    6.33 (high) years

Behavior

Although kowaris can climb well, they are a ground dwellers that move with a bounding gait. A single animal can occupy several burrows, each with multiple entrances. They sometimes share burrows with another conspecific or a colony. Individuals may dig their own burrows or take over an abandoned burrow. Males and females build nests of leaves and other soft materials, where they sleep. Although kowaris sleep in shared burrows, they forage alone. Juveniles have been observed grooming each other, but this behavior is rare in adults. Kowaris can leap over 43 cm in the air.

Kowaris are primarily nocturnal, but they are sometimes active in the early morning as well. Their activity schedule is dictated by light and dark cycles, much like that of a rodent. Kowaris shiver more in hot temperatures than in cold temperatures, which is believed to be a thermoregulatory strategy. Kowaris enter torpor when temperatures are cold or when food is scarce. ("Animal Info - Kowari", 2005; "Kowari (Dasycercus byrnei)", 2006; Hutson, 1976; Kennedy, 1989; May, 2003; "Kowari (Dasyuroides byrnei)", 2012)

  • Average territory size
    3 km^2

Home Range

The home range of both male and female kowaris is several square kilometers and can overlap with other individuals. Average home range size is 3 sq km. Kowaris mark their territies. ("Animal Info - Kowari", 2005)

Communication and Perception

Kowaris scent-mark their territories with feces, urine, and a scent from a gland located in its chest. To utilize scent glands on the sternal and cloacal regions, they sand bathe.

Kowaris also communicate through vocalizations and body language. For example, responses to threats from predators or other kowaris include hissing (with an open mouth) and a raucous chattering. Dependent young make a grating call. When agitated, kowaris angrily move their tails from side to side, much like an upset cat. Males act aggressively towards each other, but injuries rarely occur. ("Kowari (Dasyuroides byrnei)", 2012)

Food Habits

Kowaris are completely carnivorous and primarily consume invertebrates. They also consume small vertebrates such as rodents, birds and their eggs, lizards, and occasionally carrion. Their teeth have excellent shearing capacity, which allows them to finely grind prey items such as Tenebrio larvae. Water is obtained through items in their diet.

Kowaris use olfaction to detect prey. They do no stalk prey, but pick up prey items with their mouth or paws. While small prey are eaten immediately, bigger prey items are carried off and eaten at a different site. ("Animal Info - Kowari", 2005; "Kowari (Dasycercus byrnei)", 2006; Hutson, 1975; Moore, 1995)

  • Animal Foods
  • birds
  • mammals
  • reptiles
  • eggs
  • carrion
  • insects
  • terrestrial non-insect arthropods

Predation

Known predators of kowaris include introduced mammals such as red foxes (Vulpes vulpes) and feral cats (Felis silvestris catus) and dogs (Canus lupis familiaris), as well as native animals like quolls (Dasyurus) and owls (Strigiformes). ("Animal Info - Kowari", 2005)

Ecosystem Roles

Kowaris are believed to be an indicator for presence of dingos (Canis lupus dingo). They may affect populations of insects that they prey upon. (Wallach, 2009)

Economic Importance for Humans: Positive

Kowaris may affect populations of insects that they prey upon.

Economic Importance for Humans: Negative

There are no known adverse effects of kowaris on humans. ("Animal Info - Kowari", 2005)

Conservation Status

Dasyuroides byrnei has been listed by the IUCN as "vulnerable" since 2004. A survey in 2009 estimated that there are less than 10,000 individuals in the wild. Causes for population decline include introduced predators (red foxes, feral cats, feral dogs), introduced grazers that reduce the amount of cover and food for invertebrates (cattle, goats, European rabbits), removal of gibber, and increased frequency of roadkill due to increasing number of roads through gibber plains.

Some kowaris live in protected areas such as Diamantina and Astrebla Downs National Parks. Additional research on the ecology of the species as well as identification of specific threats and high priority conservation areas are needed. Suggested management practices include management of hydrology, development of control and eradication plans for red foxes and feral goats, teaching the public about kowaris, and establishing new populations. ("Kowari Dasyuroides byrnei", 2006; Department of Sustainability, Environment, Water, Population and Communities, 2012)

Other Comments

Common names for Dasyuroides byrnei include kowari, brush-tailed marsupial rat, Byrne's crest-tailed marsupial rat, bushy-tailed marsupial rat, Kayer rat, and kawiri. ("Kowari (Dasyuroides byrnei)", 2012)

Contributors

Alyssa DeRubeis (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Gail McCormick (editor), Animal Diversity Web Staff.

Glossary

Australian

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

World Map

acoustic

uses sound to communicate

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.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

crepuscular

active at dawn and dusk

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.

female parental care

parental care is carried out by females

fossorial

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

insectivore

An animal that eats mainly insects or spiders.

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

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

tactile

uses touch to communicate

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

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

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.

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

2005. "Animal Info - Kowari" (On-line). Animal Info - Endangered Animals. Accessed February 17, 2012 at http://www.animalinfo.org/species/dasybyrn.htm.

Wildscreen. 2012. "Kowari (Dasyuroides byrnei)" (On-line). ARKive. Accessed March 19, 2012 at http://www.arkive.org/kowari/dasyuroides-byrnei/#text=Biology.

2006. "Kowari (Dasycercus byrnei)" (On-line). AustralianFauna.com. Accessed February 21, 2012 at http://www.australianfauna.com/kowari.php.

Northern Territory Government Department of Natural Resources, Environment and the Arts. Kowari Dasyuroides byrnei. NA. Palmerston, Northern Territory: Chris Pavey. 2006. Accessed February 17, 2012 at http://www.nretas.nt.gov.au/__data/assets/pdf_file/0013/10840/kowari_dd.pdf.

Aslin, H. 1980. Biology of a laboratory colony of Dasyuroides byrnei (Marsupialia: Dasyuridae). Australian Zoologist, 80: 457-472.

Department of Sustainability, Environment, Water, Population and Communities, 2012. Dasyuroides byrnei in Species Profile and Threats Database, Department of Sustainability, Environment, Water, Population and Communities, Canberra. Accessed March 08, 2012 at http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=329.

Hutson, G. 1976. Grooming behavior and birth in the dasyurid marsupial Dasyuroides byrnei. Australian Journal of Zoology, 24: 277-282.

Hutson, G. 1975. Sequences of prey-catching behaviour in the brush-tailed marsupial rat (Dasyuroides byrnei). Zeitschrift fur Tierpsychologie, 39: 39.

Kennedy, G. 1989. Phase-response curve to 1-hour light pulses for the marsupial Dasyuroides byrnei. Physiology and Behavior, 46: 667-670.

Kortner, G. 2011. Activity and torpor in two sympatric Australian desert marsupials. Journal of Zoology, 283: 249-256.

May, E. 2003. Effects of cold acclimation on shivering intensity in the kowari (Dasyuroides byrnei), a dasyurid marsupial. Journal of Thermal Biology, 28: 477.

Moore, S. 1995. A comparison of the molar efficiency of two insect-eating mammals. Journal of Zoology, 235: 175-192.

Wallach, A. 2009. Threatened species indicate hot-spots of top-down regulation. Animal Biodiversity and Conservation, 32: 127-133.

Woolley, P. 1988. Phallic morphology of Dasyuroides byrnei and Dascercus cristicauda Marsupialia Dasyridae. Australian Journal of Zoology, 35: 535-540.

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