Common Water Rat vs Oriental House Rat

Hydromys chrysogaster compared with Rattus tanezumi

Taxonomic Classification

Rank	Common Water Rat	Oriental House Rat
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (cordados)	Chordata (cordados)
Class same	Mammalia (mamíferos)	Mammalia (mamíferos)
Order same	Rodentia (Roedores)	Rodentia (Roedores)
Family same	Muridae (Mice & Rats)	Muridae (Mice & Rats)
Genus	Hydromys	Rattus
Species	Hydromys chrysogaster	Rattus tanezumi

Evolutionary Relationship

Common Water Rat and Oriental House Rat share a common ancestor at the Family level: Muridae. (Mice & Rats)

Conservation Status

Common Water Rat

LC — Least Concern

Oriental House Rat

LC — Least Concern

Physical Characteristics

Attribute	Common Water Rat	Oriental House Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Oriental House Rat

Habitat

Inhabits tropical and subtropical moist broadleaf forests within the Oceanian biogeographic realm.

Range

Widely distributed across Africa (Eswatini, Lesotho, South Africa), Asia (Philippines, Taiwan), and Oceania and the Pacific (Kiribati).

Common Water Rat

<em>Hydromys chrysogaster</em>, commonly known as the common water rat or rakali, is a semi-aquatic rodent in the family Muridae, native to Australia and New Guinea. It is classified as Least Concern by the IUCN, reflecting its relatively stable population across a broad range of freshwater and estuarine habitats on the Australian continent and associated islands. The species typically inhabits the banks of rivers, lakes, wetlands, and estuaries, where it constructs burrows in streambanks. It is highly adapted for an aquatic lifestyle, with partially webbed hind feet, a flattened head, and a dense waterproof coat. <em>Hydromys chrysogaster</em> is a carnivore, typically feeding on fish, crustaceans, mussels, frogs, and aquatic invertebrates, which it often carries to elevated feeding platforms to consume. The species is nocturnal and crepuscular, most active during early morning and evening hours near the water's edge. Biological traits including average lifespan, body length, and weight remain poorly documented in standardized databases, though adults are generally robust for a rodent, reportedly reaching body lengths of 20–35 cm excluding the tail. Geographic range details for this particular record remain incompletely documented in available data sources. Ecologically, the common water rat is an important apex predator in small-scale freshwater food webs and serves as an indicator species for wetland health in Australian riparian systems.