Kowari (Dasyuroides byrnei)

Also known as: brush-tailed marsupial rat, bushy-tailed marsupial rat, Byrne’s crest-tailed marsupial rat, kawiri, Kayer rat
Synonyms: Dasycercus byrnei
French: Rat Marsupial À Double Crête
GenusDasyuroides (1)
SizeHead-body length: 13.5 - 18.2 cm (2)
Tail length: 11 - 14 cm (2)
Weight70 - 140 g (2)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The kowari is a robust, rat-like carnivorous marsupial, with a pointed snout and a distinctive black brush on the terminal half of the tail, which may have a signalling function. In contrast to the tail brush, the body and the rest of the tail are light grey-brown to sandy-brown in colour, with a faint reddish tinge, and the underparts are whitish (2) (3) (4) (5). The body fur is soft and dense (2). The head of the kowari is rather pointed, with large eyes and thin, sparsely-haired ears, and the limbs are quite long, with narrow hind feet that lack a first toe. The male kowari is larger than the female (2) (4). The calls of this species include a loud, defensive staccato chattering, and a threatening hiss that is accompanied by vigorous tail movements (4).

The kowari occurs in Australia, where it is patchily distributed in southwest Queensland and northeast South Australia (1) (2) (5) (6). Although previously recorded in the Northern Territory, its presence there is now doubtful (5) (6).

The kowari inhabits patches of gibber plain (stony desert with sparse scrub vegetation) between grassland, sand dunes and river channels (1) (2) (4) (5) (6).

Although it climbs well, and is also capable of large vertical leaps (2), the kowari is primarily terrestrial. Most active at night, it runs with a bounding gait, and shelters by day in a burrow in which it constructs a sleeping nest of leaves and other soft materials. The kowari may dig its own burrow, or take over and modify that of another species. Each burrow may have several entrances, and an individual may use a number of different burrows, sometimes sharing with other kowaris. The kowari takes a variety of prey, including insects, spiders, small vertebrates and carrion, and may enter short periods of torpor when food is scarce (2) (4).

Kowaris occupy overlapping ranges, which are scent-marked with urine, faeces, and secretions from a gland on the chest (4). Mating takes places between April and December, the female giving birth to between 2 and 7 young after a gestation period of 30 to 36 days. The rather underdeveloped young, which measure a mere 4 millimetres long at birth, attach firmly to a teat within the female’s partially enclosed pouch, until about 56 days old. After this, the young are left in the nest or ride on the female’s back, until weaned at about 95 to 100 days. The female may then go on to produce a second litter. The kowari reaches maturity at around 10 to 11 months, and can live for up to 7 years in captivity (2) (4) (7).

Kowari numbers naturally fluctuate with climatic conditions, but overall the species is undergoing a decline, with a population now estimated at fewer than 10,000 mature individuals (1). The kowari is thought to be under threat from the clearance of vegetation due to agriculture and overgrazing by cattle, rabbits and goats, which reduces cover and food for the kowari’s prey. Introduced predators such as dogs, cats and foxes may also be a problem, both as predators and competitors, although their impact on the kowari population is not clear (2) (4) (5) (6) (8). Road building and an increase in traffic are also a potential threat, particularly as the stones of gibber plains are often taken to be used as a road base (5) (6) (8).

The kowari is listed as a threatened species in Australia, and occurs in a few protected areas within its range, including Diamantina and Astrebla Downs National Parks (1). A range of conservation measures have been recommended for the species, including long-term population monitoring, habitat management, research into the impacts of cattle grazing, the surveying of additional sites where the species may occur, and further studies into its biology and ecology (5) (6) (8). Introduced species such as foxes and rabbits may also need to be controlled if the kowari is to survive and thrive in the long-term (8).

To find out more about the conservation of this and other marsupials, see:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

  1. IUCN Red List (December, 2009)