Water Mouse

Xeromys myoides

Conservation status: Vulnerable

Found in saltmarsh, samphire shrub lands, mangroves and coastal freshwater wetlands, the Water mouse is a native rodent and considered Australia’s rarest.

Water Mouse.

Water Mouse

Xeromys myoides

Conservation Status
Queensland State: Vulnerable
Australian Government: Vulnerable

Species and status overview
Found in saltmarsh, samphire shrub lands, mangroves, and coastal freshwater wetlands, the Water mouse is a native rodent and considered Australia’s rarest.

The Proserpine area is thought to be the most northern extent of its range within Queensland, with the distribution then spreading southwards to the NSW border.

The Water mouse has been recorded in the Mackay and Whitsunday region in the following areas

  • Repulse Bay
  • Thompsons Creek
  • Cape Hillsborough
  • Bucasia
  • Slade Point
  • Bakers Creek
  • Sandy Creek
  • Llewellen Bay
  • Cape Palmerston NP

The Water mouse has a white belly and silky slate-grey fur that is sometimes spotted white on the back and is water resistant. They have small eyes, short round ears and a short tail. They are relatively small (average weight 42g), distinguishing them from other species in similar habitat.

Thought to be entirely nocturnal, the Water mouse is carnivorous and feeds on invertebrates, crabs, snails and other gastropods make up the majority of their diet. The Water mouse seeks food amongst mangrove roots and in shallow pools that they visit regularly, depositing the remains of their meals in middens.

A strong, long-lasting pheromone (hormone) is excreted from the Water mouse’s enlarged anal gland. Laid in trails, the pheromone can survive tidal inundation and allows the Water mouse to follow regularly along their own tracks.

Interestingly, while employing a range of nesting strategies in other regions, in the Mackay region the Water mouse appears to only use sloping mud nests built among the buttress roots of mangrove trees. In other areas nests can be observed on small, elevated sedgeland islands within the bank and above high water, or in living or dead trees.

Water mouse mounds can have a separate defecation chamber or toilet.

Conservation concerns
Common known threats include

  • The loss, degradation and fragmentation of freshwater and intertidal wetland communities, including through coastal and industrial development
  • Habitat degradation through weed invasion including para grass and olive hymenachne
  • Changes to hydrology (e.g. increased freshwater inflows and sedimentation from storm water runoff) as a result of adjacent residential development
  • Runnelling or bundwall construction
  • Recreational vehicles causing the destruction and degradation of habitat
  • Drainage of coastal and terrestrial wetlands for urban and industrial development
  • Inappropriate burning of sedgeland and adjacent Melaleuca wetland communities
  • Predation by feral and domestic dogs, foxes and cats
  • Competition for food resources and modification of habitat by feral pigs
  • Sea level rise caused by climate change

What can I do?

  • Control domestic animals including cats and dogs that may prey on the Water mouse
  • Avoid the use of herbicides and pesticides in areas adjacent to Water mouse habitat
  • Avoid landscape modifications such as excavation, construction of bund walls or the discharge of polluted water in habitat areas
  • Do not drive in inter-tidal areas
  • Reduce grazing pressure in known Water mouse habitat

More Information

Photo credit Derek Ball