Perception Channels: tactile ; chemical
Rattus lutreolus is common throughout its limited range. Most of its original habitat has now been farmed and made unsuitable for this species (Strahan 1995).
IUCN Red List of Threatened Species: least concern
The swamp rat was hunted by Aborigines prior to European settlement and provided a significant source of meat;however, this hunting pressure no longer exists (Strahan 1995).
Stems and leaves are the main foods eaten by R. lutreolus. In spring and early summer, their diet expands to include seeds, fleshy fruits, and insects. Roots and underground fungi are also consumed by R. lutreolus (Cheal 1987, Norton 1987).
This species is common over a wide area of south-eastern Australia. One subspecies is also found on the north-eastern cosat (Strahan 1995).
Biogeographic Regions: australian (Native )
Rattus lutreolus prefers poorly drained habitats, heathland, and sedges. This species has also been found on dry ridges in open forest. Density of vegetation seems to be the most important requirement of this species. This is most likely a result of selection for evasion of avian predators, or perhaps because food is more abundant in dense habitats. Habitat selection by females is most likey related to the amount of energy required for reproduction. Members of this species can survive without free water (Haering and Fox 1995, Monamy 1995, Strahan 1995).
Terrestrial Biomes: savanna or grassland ; forest
Status: captivity: 1 (high) years.
Status: wild: 2.4 (high) years.
Head and body length of this species ranges from 122mm to 197mm and the tail length is an additional 56-147mm. Rattus lutreolus is dark gray or gray brown on its dorsal surfaces and cream to brown on its ventral surface. The fur on the upper half of the body is golden-tipped. Its ears are small and nearly concealed by hair. The tail is dark gray, scaly and sparsely haired (Strahan 1995).
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 115 g.
Average basal metabolic rate: 0.353 W.
The breeding season is generally from early spring to autumn, but breeding can occur throughout the year. The gestation period is three weeks and the female gives birth to three to five young, each weighing approximately 5 grams. A female may produce several litters in a year and a three month old female from an early spring litter may be reproductively active that same year. Females are usually aggressive toward males except during mating (Monamy 1995, Strahan 1995).
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 4.87 g.
Average gestation period: 27 days.
Average number of offspring: 5.
Average age at sexual or reproductive maturity (female)
Sex: female: 79 days.
The Australian swamp rat grows to have a body length of approximately 160 millimetres (6 in) with a tail length of approximately 110 mm (4.3 in) and a mass of about 120 grams (4 oz). It has a stocky build with black-brown fur and black feet. Its ventral surface is cream to brown color and it has small ears nearly concealed by hair. The tail is dark grey, scaly and sparsely haired.
The Swamp Rat is found near the coast of south and eastern Australia. It occurs in lowland country from Fraser Island down the coast of New South Wales and Victoria to the Mount Lofty Ranges in South Australia. A subspecies velutinus can be found in Tasmania, and another subspecies lacus lives in isolated patches of high altitude rainforest near Atherton, Queensland.
The preferred habitat of the swamp rat is thick vegetation along watercourses and in swamps. Dense vegetation of islands above the high water mark is also suitable. They can also live in area of coastal heath, dune scrub, grasslands and sedgelands. The rats will form tunnels through the vegetation through which they can move. The species tends to choose the habitat based on density of vegetation in the area. Areas prone to fire tend not to be recolonised. The swamp rat can be seen at places like the Healesville Sanctuary, where they live in the grounds.
The diet is vegetarian; consisting of reeds, seeds and swamp grass stems. During the summer months, the species will increase its intake of insects as well as fungi; however, during spring months the rats switch to eating an increased amount of seeds due to their abundance and possible nutritional value in breeding season.
Behaviour is partly nocturnal and diurnal so it is active during the day and at night. It is thought that the species does not collect the sufficient amount of food throughout the night and must also collect vegetation during the day.
The rats reach sexual maturity around August and start to breed come October. The species has a litter size ranging from one to eleven on average with a gestation period lasting around 23 to 25 days. Olfactory senses are used to smell certain species' odours, allowing them to detect predators.