Brown Rat vs Common Eider

Rattus norvegicus compared with Somateria mollissima

Key Differences

• Brown Rat is Least Concern while Common Eider is Near Threatened.

Taxonomic Classification

Rank	Brown Rat	Common Eider
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Mammalia (Mammals)	Aves (Birds)
Order	Rodentia (Rodents)	Anseriformes (Anseriformes)
Family	Muridae (Mice & Rats)	Anatidae
Genus	Rattus	Somateria
Species	Rattus norvegicus	Somateria mollissima

Evolutionary Relationship

Brown Rat and Common Eider share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Brown Rat

LC — Least Concern

Common Eider

NT — Near Threatened

Physical Characteristics

Attribute	Brown Rat	Common Eider
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 Eider

Habitat

Typically found in various aerial, terrestrial, and aquatic environments.

Range

Found across Europe (5 countries) and North America (United States). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

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 Eider

Common Eider (Somateria mollissima) is classified as Near Threatened (NT) on the IUCN Red List. Close to qualifying as threatened, with populations that may become vulnerable without conservation action.

Shared Countries

Both species can be found in 6 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden 🇺🇦 Ukraine 🇺🇸 United States