Bigeye thresher vs Lesser Siren

Alopias pelagicus compared with Siren intermedia

Key Differences

• Bigeye thresher is Endangered while Lesser Siren is Least Concern.

Taxonomic Classification

Rank	Bigeye thresher	Lesser Siren
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Chondrichthyes (Cartilaginous Fish)	Amphibia (Amphibians)
Order	Lamniformes (Mackerel Sharks)	Caudata (Caudata)
Family	Alopiidae	Sirenidae
Genus	Alopias	Siren
Species	Alopias pelagicus	Siren intermedia

Evolutionary Relationship

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

Conservation Status

Bigeye thresher

EN — Endangered

Lesser Siren

LC — Least Concern

Physical Characteristics

Attribute	Bigeye thresher	Lesser Siren
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.

Lesser Siren

Habitat

Typically found in freshwater habitats, moist forests, and wetlands.

Range

Distributed across Belgium and Mexico.

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.