common nut clam vs Polar bear

Nucula nucleus compared with Ursus maritimus

Key Differences

• common nut clam is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	common nut clam	Polar bear
Kingdom same	Animalia (动物界)	Animalia (动物界)
Phylum	Mollusca (软体动物门)	Chordata (脊索动物门)
Class	Bivalvia (双壳纲)	Mammalia (哺乳動物)
Order	Nuculida (银锦蛤目)	Carnivora (食肉目)
Family	Nuculidae	Ursidae (Bears)
Genus	Nucula	Ursus (Bears)
Species	Nucula nucleus	Ursus maritimus

Evolutionary Relationship

common nut clam and Polar bear share a common ancestor at the Kingdom level: Animalia. (动物界)

Conservation Status

common nut clam

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	common nut clam	Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

common nut clam

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Polar bear

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common nut clam

<em>Nucula nucleus</em>, the common nut clam, is a small marine bivalve mollusk in the family Nuculidae, among the most primitive living bivalves in terms of evolutionary lineage. This deposit-feeding species typically burrows into soft sediments — muddy and sandy substrates — in coastal and subtidal marine environments. <em>Nucula nucleus</em> uses its elongated palp proboscides to sort organic particles and detritus from sediment, making it a key functional contributor to benthic nutrient cycling. Its geographic range spans European Atlantic and Mediterranean coasts, with documented occurrences in Belgium, Denmark, Norway, and Sweden, typically in sheltered bays, estuaries, and sublittoral soft-bottom habitats. The species is currently assessed as Least Concern by the IUCN. Biological traits such as lifespan, body size, and diet remain poorly documented at a population level for this species in formal assessments, though it is known as a selective deposit feeder. The common nut clam plays an important role in benthic community structure and sediment processing, and serves as prey for demersal fish, sea stars, and other bottom-dwelling predators across its European range.

Polar bear

北极熊是地球上最大的陆地食肉动物，体重可超过700千克，分布于从加拿大到俄罗斯的北极海冰区。是高度特化的海洋哺乳动物，依赖海冰捕猎环斑海豹和髯海豹。是优秀的游泳者，能够横渡广阔的开阔水域。被列为易危种，因气候变化导致北极海冰迅速减少，种群正受到严重威胁。

Shared Countries

Both species can be found in 1 countries:

🇳🇴 Norway