The geographic range of Xeromys myoides is restricted to Australia. Though originally known only in Southeast Queensland and the Northern Territory, the false water-rat is currently found in the central and southern parts of Queensland, North Stradbroke Island off the coast of Southeast Queensland, the Northern territory, and on the nearby Melville Island (Wilson and Reeder, 1993; Nowak, 1999)
Biogeographic Regions: australian (Native )
False water-rats have markedly long, flattened heads with small eyes and short, rounded ears. These rats possess just two molars on each side of the upper and lower jaw. Their upper incisors are yellow or orange and the lower incisors are white.
The head and body length of the false water-rat is 115-27mm. The tail length is 85-100mm and the hind-foot length is 23-26mm. Body fur is generally dark gray, which gradually blends into the white underside. This coat is water-resistant. The hands, feet, and tail are covered with fine, white hairs, and the feet are not webbed. The tail of these rats is scaled.
Females have four teats (Nowak, 1999; Taylor, 1984).
Range mass: 40 to 60 g.
Other Physical Features: endothermic ; bilateral symmetry
The false water-rat is found mainly in coastal swamps with mangrove forest. It has also been recorded near freshwater lagoons, sedged lakes, and grassy and reed swamps. It appears to dependend on mangrove habitats for food aquisition (Nowak, 1999; Strahan, 1995).
Terrestrial Biomes: savanna or grassland
Aquatic Biomes: coastal
Habitat and Ecology
The false water-rat's diet is very much dependent on its swampy habitat. They appear to feed on small crustaceans such as crabs, marine polyclads, marine pulmonates, shellfish, and worms. In captivity, the false water-rat will eat insects, fish, lizards, crabs that are larger than itself (Nowak, 1999; Van Dyck, 1997; Queensland Museum Explorer, 1999).
Life History and Behavior
Perception Channels: tactile ; chemical
Very little is known about the false water-rat's reproductive behavior. It is thought to be in breeding condition throughout the year. Litter size does not exceed 2 (Van Dyck, 1997; Taylor, 1984).
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Since its initial description in 1889, only a very small number of specimens have been collected, mostly since 1970. It is evident that these rats are intimately connected to their mangrove habitat. Habitat distruction due to agriculture, livestock grazing, urbanization, and swamp drainage are considered major threats to the survival of this animal. In addition, off-shore pollution and land reclamation pose a threat to this rare species (Queensland Museum Explorer, 1999; Strahan, 1995; Nowak, 1999).
CITES: appendix i
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1994Rare(Groombridge 1994)
- 1990Rare(IUCN 1990)
- 1988Insufficiently Known(IUCN Conservation Monitoring Centre 1988)
- 1986Insufficiently Known(IUCN Conservation Monitoring Centre 1986)
- 1982Insufficiently Known(Thornback and Jenkins 1982)
Date Listed: 12/02/1970
Lead Region: Foreign (Region 10)
Where Listed: Australia
Population location: Australia
Listing status: E
For most current information and documents related to the conservation status and management of Xeromys myoides , see its USFWS Species Profile
Relevance to Humans and Ecosystems
The false water-rat does not appear to negatively effect humans or the economy.
The false water-rat has no positive economic importance for humans. But by playing a role in maintaining the ecological stability of the marine population it feeds on, it may indirectly effect local marine-related industries.
False water rat
False water rats have markedly long, flattened heads with small eyes and short, rounded ears. These rats possess just two molars on each side of the upper and lower jaw. Their upper incisors are yellow or orange and the lower incisors are white. The head and body length is approximately 100 mm characterised by a hunched body shape. The tail length is 85–100 mm and the hind-foot length is 23–26 mm. The body fur is water-resistant and dark gray, which gradually blends into the white underside. The hands and feet are covered with fine, white hairs. Their feet are not webbed like other water rats (Hydromys chrysogaster), which gives it their common name "false" water rat. The tail is sparsely haired and lacks the white-tip found in the more common water rat. In addition, the tails of these rats, are scaled. The average weight is 42 grams.
The false water rat (Xeromys myoides) lives in Australia and Papua New Guinea. Though originally believed to be restricted to Southeast Queensland and the Northern Territory, the false water rat has subsequently been found in the central and southern parts of Queensland, North Stradbroke Island off the coast of Southeast Queensland, Melville Island, and southwest Western Province, Papua New Guinea. False water rats primarily live in mangrove communities and shallow areas surrounding lagoons, swamps, and lakes. Their nests are made at the base of mangrove trees. Their nests are very similar to termite mounds. They are made of leaves, mud, and may be as high as 60 centimetres. There is usually one opening and on the inside it is a complex system of tunnels which connects to multiple chambers. Since the tunnels are very complex sometimes the homes can overlap. This behaviour shows that they are social and very friendly. Because of their lack of webbed feet and their inability to swim, their nests are generally built near shallow water. This allows them to wade in water instead of swimming and diving in search of their food.
False water rats appear to depend on mangrove and intertidal salt marsh habitats for food. Their diet consists of invertebrates such as crabs, small mud lobsters, marine shellfish, snails and worms. They generally eat during the night and rest during the day. Their estimated home range used for foraging is 0.8 ha for males and 0.6 ha for females, however they can forage up to 2.9 km distances at night.
Life Cycle and Reproduction
Little is known about the life cycle and breeding patterns of this species. Since their food and nutrients are generally found amongst the mangroves, the lifespan of the false water rat is highly dependent upon the preservation of the mangrove forest. It is believed that they breed throughout the year with only two young per litter. Up to eight individuals of various ages (young and old) and either sex live in a nest, with usually only one sexually active adult male present and several females.
Predators and Threats
There are several predators to the false water rat including foxes, cats, carpet pythons, rough-scaled snakes, tawny frog mouths, and pigs. However, the biggest threat to the false water rat is man. Due to man, their habitat is severely fragmented and less than 2,000 km. The quality of their habitat and area of occupancy continue to decline primarily due to the development of mangrove areas. Increasing development creates oil pollution, wastewater and acid sulphate contamination, alteration of natural hydrology, and increasing infections from chemicals and waste. Overall, the habitat is being destroyed because of water quality changes due to agriculture, livestock grazing, urbanisation, and swamp drainage. Because of all of these circumstances, they are classified as vulnerable.
False water rats do not appear to negatively affect man or our economy and they have no known positive economic importance for man other than playing a role in maintaining the ecological stability of the marine population it feeds on, indirectly affecting local marine-related industries and the land. Through the years, man has been careless with the release of pollutants and other waste products thereby causing a decrease in the habitat for these animals. Paying particular attention, creating, promoting and maintaining environmental safe processes surrounding excavation and construction, garbage and waste products elimination, chemicals and extracts usage, as well natural and unnatural predators will increase the survival chances of the false water rat. In addition, conservation of the wetlands and mangroves will not only prevent extinction of the false water rat and other animals but it will protect our shores from wave action, reduce the impacts of floods and absorb natural pollutants and provide habitat for animals and plants.
The common name of this species has long been False Water-rat. During the 1990s there was a push for such descriptive English common names to be replaced with indigenous names. In 1995 the Australian Nature Conservation Agency released a document in which were recorded two indigenous names for H. chrysogaster, the Murrinh-Patha name Manngay and the Mayali and Gunwinjgu name Yirrku. They recommended that the latter name be adopted as the common name, but with the orthography Yirrkoo. However, this recommendation was not prescriptive, and it remains to be seen to what extent it will be adopted.
- l "False Water Rat.". 4 November 2008.
- "Water Mouse (False Water Rat)". Queenland Government Environmental Protection Agency. 4 November 2008.
- "Water mouse (or false water-rat) Xeromys myoides". Queensland Government Environmental Protection Agency.
- "False Water Rat, Xeromys myoides". Threatened Species Day Fact Sheet. Australian Government, Department of the Environment,Water,Heritage,and the Arts. 2003.
- "False Water Rat (Xeromys myoides)". Australianfauna.com. 4 November 2008.
- Suter, M (2000). "Xeromys myoides (On-line)". Animal Diversity Web. Retrieved 25 November 2008.
- Braithwaite R. W. et al. (1995). Australian names for Australian rodents. Australian Nature Conservation Agency. ISBN 0-642-21373-9.
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