Bigeye thresher vs Common Loon

Alopias pelagicus compared with Gavia immer

Key Differences

• Bigeye thresher is Endangered while Common Loon is Not Evaluated.

Taxonomic Classification

Rank	Bigeye thresher	Common Loon
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Chondrichthyes (Cartilaginous Fish)	Aves (Birds)
Order	Lamniformes (Mackerel Sharks)	Gaviiformes (Gaviiformes)
Family	Alopiidae	Gaviidae
Genus	Alopias	Gavia
Species	Alopias pelagicus	Gavia immer

Evolutionary Relationship

Bigeye thresher and Common Loon share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Bigeye thresher

EN — Endangered

Common Loon

NE — Not Evaluated

Physical Characteristics

Attribute	Bigeye thresher	Common Loon
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Bigeye thresher

Habitat

Typically found in marine environments from coastal waters to deep ocean.

Range

Distributed across Colombia and Taiwan. Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Loon

Habitat

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

Range

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

Bigeye thresher

The Bigeye thresher (Alopias pelagicus) is a species in the genus Alopias. It is currently classified as Endangered on the IUCN Red List. Typically found in marine environments from coastal waters to deep ocean.

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.