Mastacomys fuscus Click to enlarge image
,Smiggins Holes N.S.W Image: G A Hoye
© Australian Museum

Fast Facts

  • Classification
  • Size Range
    17.5 cm

Broad face, short tail and stocky body; brown-tinged with rufous fur colour; small round ears.


A medium-sized native rat with a broad face, short tail and stocky body. The fur is soft, dense and brown-tinged with rufous on the dorsal side merging to grey underneath. It may have a green tinge due to the presence of algae. The ears are small and round with tufts of hair inside. The feet are brown above and below and the tail is lightly haired, dark above becoming slightly lighter underneath. The molar teeth are characteristically large.


Alpine and subalpine heaths and eucalypt woodlands, wet sclerophyll forest, grasslands and wet sedgelands from sea level to 2200m.


Patchy distribution that includes Barrington Tops, Snowy Mountains, Eastern Highlands, Victorian Alps, Otway Ranges, Wilsons Promontory and western Tasmania.

Feeding and diet

It remains active in runways underneath the snow during winter and feeds mainly on the stems, leaves and seeds of grasses and sedges. Shrub foliage, fungi, bark and moss are also eaten.

Other behaviours and adaptations

This rare native rodent prefers high rainfall areas with low temperatures and moderate to dense ground cover of grasses, shrubs or boulders. It is largely nocturnal, sheltering by day, sometimes communally, in grass nests under dense vegetation or logs.

Breeding behaviours

Breeding is seasonal with births occurring during summer months. The gestation period is around 5 weeks and litter size ranges from 1-4. This species has declined significantly and is currently threatened by habitat loss and fragmentation, predation by foxes and cats and possibly climate change.

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