Bigeye thresher vs Black-headed Gull

Alopias pelagicus compared with Chroicocephalus ridibundus

Key Differences

• Bigeye thresher is Endangered while Black-headed Gull is Vulnerable.

Taxonomic Classification

Rank	Bigeye thresher	Black-headed Gull
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Chondrichthyes (Cartilaginous Fish)	Aves (Birds)
Order	Lamniformes (Mackerel Sharks)	Charadriiformes (Charadriiformes)
Family	Alopiidae	Laridae
Genus	Alopias	Chroicocephalus
Species	Alopias pelagicus	Chroicocephalus ridibundus

Evolutionary Relationship

Bigeye thresher and Black-headed Gull share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Bigeye thresher

EN — Endangered

Black-headed Gull

VU — Vulnerable

Physical Characteristics

Attribute	Bigeye thresher	Black-headed Gull
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.

Black-headed Gull

Habitat

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

Range

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

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.

Black-headed Gull

Black-headed Gull (Chroicocephalus ridibundus) is classified as Vulnerable (VU) on the IUCN Red List. Facing a high risk of endangerment in the wild, with declining populations and increasing habitat pressure.

Shared Countries

Both species can be found in 2 countries:

🇨🇴 Colombia 🇹🇼 Taiwan