Scientific Name: Hydromis chrysogaster
IUCN Status: Common
Length: 23–37 cm
Weight: 340–1275 g
Gestation: 24–34 days
Number of young: 3–4

Distribution: East, northern and south-western Australia and Papua New Guinea
Habitat: On the banks of lakes, streams and other bodies of water

Description: Apart from the platypus, the Water Rat is the only amphibious land-based Australian mammal. It has broad, partially-webbed hindfeet, water-repellent fur and many whiskers. The Water Rat varies in colouration from brown to grey-brown or black on its back with a pale belly. The tail is long, sparsely haired and 22–32 cm long. Females are slightly larger than males.

Diet: The Water Rat is a carnivore and eats aquatic insects, fish, crustaceans and mussels. Frogs, lizards, small mammals and water birds might also be eaten.

In the wild: Unlike many Australian rodents, the Water Rat is not entirely nocturnal. It is most active around sunset and has been seen foraging during the day. They are slightly clumsy on land and can climb hollow trees in search of prey. However, they prefer to catch their prey in the water.

Snakes and large fish are natural predators of young Water Rats while birds of prey and cats hunt both adult and young Water Rats.

Threats: The Water Rat is regarded as a pest of inland fisheries and its burrows are said to damage irrigation.

At Perth Zoo: The Water Rat can be seen swimming in its exhibit in the Nocturnal House.