Brown Rat vs common freshwater nerite

Rattus norvegicus compared with Theodoxus fluviatilis

Taxonomic Classification

Rank	Brown Rat	common freshwater nerite
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chordata (Chordates)	Mollusca (Mollusks)
Class	Mammalia (Mammals)	Gastropoda (Gastropoda)
Order	Rodentia (Rodents)	Cycloneritida (Cycloneritida)
Family	Muridae (Mice & Rats)	Neritidae
Genus	Rattus	Theodoxus
Species	Rattus norvegicus	Theodoxus fluviatilis

Evolutionary Relationship

Brown Rat and common freshwater nerite share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Brown Rat

LC — Least Concern

common freshwater nerite

LC — Least Concern

Physical Characteristics

Attribute	Brown Rat	common freshwater nerite
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brown Rat

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 10 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (11 countries), Asia (15 countries), Europe (41 countries), North America (16 countries), Oceania and the Pacific (10 countries), and South America (10 countries).

common freshwater nerite

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Found across Europe (11 countries).

Brown Rat

Brown Rat (Rattus norvegicus) is classified as Least Concern (LC) on the IUCN Red List. Widespread and abundant across its range, with stable populations and no immediate conservation concerns.

common freshwater nerite

<em>Theodoxus fluviatilis</em>, commonly known as the common freshwater nerite, is a small aquatic gastropod mollusc belonging to the family Neritidae. This species is widely distributed across Europe, with documented occurrences in Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Hungary, Latvia, Norway, and Sweden. It typically inhabits freshwater environments, including rivers, streams, and lakes, where it grazes on algae and biofilm on hard substrates such as rocks and submerged wood. The common freshwater nerite is assessed as Least Concern on conservation metrics, reflecting its broad distribution and relatively stable populations across much of its European range. Biological traits of this species remain poorly documented in the scientific literature. <em>Theodoxus fluviatilis</em> plays an ecological role as a grazer in freshwater benthic communities, contributing to the regulation of algal growth on hard surfaces. The species typically favors clean, well-oxygenated waters and can serve as an indicator of water quality in freshwater systems. Its distinctive small, dome-shaped shell with variable patterning makes it recognizable among freshwater invertebrates.

Shared Countries

Both species can be found in 11 countries:

🇦🇹 Austria 🇧🇪 Belgium 🇩🇰 Denmark 🇪🇪 Estonia 🇭🇺 Hungary 🇳🇴 Norway 🇵🇱 Poland 🇷🇸 Serbia 🇸🇪 Sweden 🇺🇦 Ukraine 🇬🇧 United Kingdom