What animal is called a water rat? - briefly
The nickname “water rat” most commonly refers to the Australian water rat (Hydromys chrysogaster), a large semiaquatic rodent native to eastern Australia’s rivers and wetlands. The label is also occasionally used for other semiaquatic rodents, such as the African water rat (Nile rat) and the European water vole.
What animal is called a water rat? - in detail
The name “water rat” applies to several semiaquatic rodents, most notably the Australian rakali (Hydromys chrysogaster) and the European water vole (Arvicola amphibius). Both species share adaptations for swimming but differ in taxonomy, appearance, and distribution.
Hydromys chrysogaster inhabits rivers, lakes, and coastal wetlands across northern and eastern Australia and southern New Guinea. The animal reaches 30 cm in body length, with a laterally flattened tail covered in dense, waterproof fur. Webbed hind feet, a muscular build, and a keen sense of smell enable efficient underwater foraging. Its diet consists of fish, crustaceans, amphibians, and occasional plant material. Breeding occurs year‑round in tropical zones; litters contain 2–5 young, which are weaned after about six weeks. The International Union for Conservation of Nature (IUCN) classifies the species as Least Concern, although habitat alteration and introduced predators pose localized threats.
Arvicola amphibius occupies riparian zones throughout Europe and western Asia. Adults measure 15–20 cm in body length, possess coarse brown fur, and lack the pronounced webbing of the rakali. The species builds burrows near water and feeds on grasses, aquatic plants, and seeds. It is primarily nocturnal, with a breeding season from spring to autumn, producing up to five litters per year. The IUCN lists the water vole as Least Concern, yet certain populations suffer from habitat loss and predation by invasive American mink.
In South America, the genus Nectomys, commonly called “water rats,” includes several species such as Nectomys sylvaticus. These rodents occupy forest streams in the Amazon basin, display elongated bodies, partially webbed feet, and a diet rich in insects and small fish. Conservation assessments vary by species, but deforestation and water pollution are recurring pressures.
All animals referred to as water rats share key traits: a preference for aquatic environments, morphological modifications for swimming, and omnivorous feeding habits. Their ecological roles include controlling invertebrate populations, dispersing plant seeds, and serving as prey for larger predators. Understanding each species’ specific requirements is essential for effective management and conservation.