Ballena azul vs common freshwater nerite

Balaenoptera musculus compared with Theodoxus fluviatilis

Key Differences

• Ballena azul is Vulnerable while common freshwater nerite is Least Concern.

Taxonomic Classification

Rank	Ballena azul	common freshwater nerite
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chordata (cordados)	Mollusca (moluscos)
Class	Mammalia (mamíferos)	Gastropoda (gastrópodos)
Order	Cetacea (Whales & Dolphins)	Cycloneritida (Cycloneritida)
Family	Balaenopteridae (Rorquals)	Neritidae
Genus	Balaenoptera (Rorquals)	Theodoxus
Species	Balaenoptera musculus	Theodoxus fluviatilis

Evolutionary Relationship

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

Conservation Status

Ballena azul

VU — Vulnerable

Population: ~15.0K

Trend: Increasing ↑

common freshwater nerite

LC — Least Concern

Physical Characteristics

Attribute	Ballena azul	common freshwater nerite
Diet	Carnivore	—
Average Lifespan	90 years	—
Average Length	30.0 m	—
Average Weight	150.0 t	—

Habitat & Geographic Range

Ballena azul

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 11 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Taiwan), Europe (4 countries), and South America (Colombia, Ecuador). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common freshwater nerite

Habitat

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

Range

Found across Europe (11 countries).

Ballena azul

El animal más grande que se conoce haya vivido en la Tierra; las ballenas azules pueden alcanzar 33 metros y 200 toneladas — sus corazones solos pesan tanto como un automóvil pequeño. Se encuentran en todos los océanos y migran entre las zonas de alimentación polares y las áreas de reproducción tropicales. Son filtradoras que consumen hasta 4 toneladas de kril al día. En peligro de extinción, con poblaciones globales estimadas entre 10.000 y 25.000 tras casi extinguirse por la caza de ballenas en el siglo XX.

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 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden