common river snail vs Laysan Duck

Viviparus viviparus compared with Anas laysanensis

Key Differences

• common river snail is Least Concern while Laysan Duck is Critically Endangered.

Taxonomic Classification

Rank	common river snail	Laysan Duck
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Aves (Birds)
Order	Architaenioglossa (Architaenioglossa)	Anseriformes (Anseriformes)
Family	Viviparidae	Anatidae
Genus	Viviparus	Anas
Species	Viviparus viviparus	Anas laysanensis

Evolutionary Relationship

common river snail and Laysan Duck share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common river snail

LC — Least Concern

Laysan Duck

CR — Critically Endangered

Physical Characteristics

Attribute	common river snail	Laysan Duck
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common river snail

Habitat

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

Range

Found across Europe (7 countries).

Laysan Duck

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and Mediterranean forests and woodlands within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Belgium, France, Netherlands, Norway, and United Kingdom. Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

common river snail

<em>Viviparus viviparus</em>, the common river snail, is a freshwater gastropod mollusk in the family Viviparidae, order Architaenioglossa. It is distributed across Europe, with populations documented in Austria, Belgium, Bulgaria, Czech Republic, France, Germany, and Hungary, among other countries, typically inhabiting slow-moving and still freshwater bodies including rivers, canals, ponds, and ditches. The species is assessed as Least Concern on the IUCN Red List. Common river snails typically live in soft-sediment benthic habitats, grazing on algae, aquatic plant material, and organic detritus using a radula — a ribbon-like feeding organ characteristic of gastropods. <em>Viviparus viviparus</em> is notable among freshwater mollusks for being viviparous, giving birth to fully formed juvenile snails rather than laying eggs, an adaptation reflected in both the genus and family names. This reproductive strategy typically results in small litter sizes but high juvenile survival compared to egg-laying mollusks. The species plays a role in benthic nutrient cycling and serves as prey for waterfowl, fish, and crayfish. Biological traits such as precise lifespan, body measurements, and population density data vary across localities and remain incompletely documented in comprehensive studies.

Laysan Duck

Laysan Duck (Anas laysanensis) is classified as Critically Endangered (CR) on the IUCN Red List. Facing an extremely high risk of extinction in the wild due to severe population decline and habitat loss.

Shared Countries

Both species can be found in 2 countries:

🇧🇪 Belgium 🇳🇴 Norway