What are the water rats that live in rivers called? - briefly
The semi‑aquatic rodents often referred to as water rats are called water voles in Europe (Arvicola amphibius) and rakali in Australia (Hydromys chrysogaster).
What are the water rats that live in rivers called? - in detail
Water rats are semi‑aquatic rodents belonging to the genus Nectomys in the family Cricetidae. The most widely recognized species are:
- Nectomys squamipes (South American water rat) – inhabits lowland rainforests and riverbanks from Colombia to Brazil.
- Nectomys rattus (Amazon water rat) – found throughout the Amazon basin, preferring swampy margins and floodplain forests.
- Nectomys palmipes (Palm‑footed water rat) – restricted to the Andean foothills and cloud forests of Ecuador and Peru.
Key characteristics:
- Morphology – elongated bodies, dense waterproof fur, partially webbed hind feet, and a laterally flattened tail that aids swimming.
- Diet – omnivorous; consumes aquatic insects, crustaceans, small fish, amphibian eggs, and fallen fruit.
- Behavior – nocturnal; constructs burrows near water, often with entrances above the high‑water mark. Excellent swimmers, capable of remaining submerged for up to 30 seconds.
- Reproduction – breeding peaks during the rainy season; litters average three to five pups, which are weaned after four weeks.
- Distribution – confined to Neotropical river systems, including the Amazon, Orinoco, and tributaries of the Atlantic and Pacific coasts.
- Conservation status – most species are listed as Least Concern by the IUCN, but habitat loss from deforestation and water pollution poses localized threats.
These rodents play a significant ecological role by linking terrestrial and aquatic food webs, controlling insect populations, and serving as prey for larger predators such as caimans and raptors. Their presence indicates relatively intact riparian ecosystems.