What is a rat called when it is underwater? - briefly
When a rat is submerged, it is referred to as a water rat.
What is a rat called when it is underwater? - in detail
The animal remains a rat regardless of its environment; there is no distinct lexical category that replaces the generic name when the creature is submerged. In everyday language people sometimes add a descriptive modifier, such as “water rat,” to indicate a rat that is currently in water or a species adapted to aquatic habitats. The modifier does not create a new taxonomic term but merely conveys context.
Several rodent species are commonly referred to as water rats because they spend considerable time in aquatic settings. Examples include:
- Australian water rat (Hydromys chrysogaster) – a native of eastern Australia, possessing webbed hind feet and dense fur for swimming.
- European water vole (Arvicola amphibius) – often called a water rat in lay usage, though it belongs to a different genus.
- North American muskrat (Ondatra zibethicus) – occasionally labeled a water rat due to its semi‑aquatic habits.
These are true species with morphological adaptations: flattened tails, waterproof pelage, and enhanced lung capacity that enable prolonged submersion. The brown rat (Rattus norvegicus) and black rat (Rattus rattus) lack such specializations but can still swim and survive briefly underwater. When a typical rat is placed in water, observers may simply describe it as “a rat swimming” or “a rat under water,” without invoking a separate nomenclature.
In scientific discourse the term “rat” remains unchanged; any reference to its aquatic state is expressed through adjectives or contextual description rather than a unique word. Consequently, the answer to the query is that no exclusive name exists—only descriptive phrases such as “water rat” or “swimming rat” are employed.