Common Loon vs Narrow-headed Slender Opossum

Gavia immer compared with Marmosops cracens

Key Differences

• Common Loon is Not Evaluated while Narrow-headed Slender Opossum is Data Deficient.

Taxonomic Classification

Rank	Common Loon	Narrow-headed Slender Opossum
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Aves (Birds)	Mammalia (Mammals)
Order	Gaviiformes (Gaviiformes)	Didelphimorphia (Didelphimorphia)
Family	Gaviidae	Didelphidae
Genus	Gavia	Marmosops
Species	Gavia immer	Marmosops cracens

Evolutionary Relationship

Common Loon and Narrow-headed Slender Opossum share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Common Loon

NE — Not Evaluated

Narrow-headed Slender Opossum

DD — Data Deficient

Physical Characteristics

Attribute	Common Loon	Narrow-headed Slender Opossum
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Loon

Habitat

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

Range

Distributed across Belgium, Denmark, Norway, Sweden, and United States.

Narrow-headed Slender Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Found in Venezuela.

Common Loon

<em>Gavia immer</em>, the common loon or great northern diver, is a large aquatic bird in the family Gaviidae, known for its haunting, yodeling calls across northern lakes. It is found in Belgium, Denmark, Norway, Sweden, and the United States, breeding on freshwater lakes in boreal and subarctic regions and wintering along marine coastlines. The common loon is adept in aerial, terrestrial, and aquatic environments, though it is most highly specialized for diving, using its strong feet positioned far back on its body to pursue fish underwater. It typically feeds on fish, supplemented by crustaceans and aquatic invertebrates. Its striking summer plumage features a black-and-white checkered back and a deep black head with a characteristic white necklace pattern. The species has not been evaluated for IUCN conservation status. Common loons require clear, fish-rich lakes for successful breeding and are sensitive to water quality degradation and human disturbance at nesting sites. Their distinctive calls are emblematic of wilderness in North America and Scandinavia.