Atlantic Gray Seal vs Great Hammerhead

Halichoerus grypus compared with Sphyrna mokarran

Key Differences

• Atlantic Gray Seal is Vulnerable while Great Hammerhead is Critically Endangered.

Taxonomic Classification

Rank	Atlantic Gray Seal	Great Hammerhead
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Mammalia (Mammals)	Chondrichthyes (Cartilaginous Fish)
Order	Pinnipedia (Seals & Sea Lions)	Carcharhiniformes (Ground Sharks)
Family	Phocidae (True Seals)	Sphyrnidae (Hammerhead Sharks)
Genus	Halichoerus	Sphyrna (Hammerhead Sharks)
Species	Halichoerus grypus	Sphyrna mokarran

Evolutionary Relationship

Atlantic Gray Seal and Great Hammerhead share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Atlantic Gray Seal

VU — Vulnerable

Great Hammerhead

CR — Critically Endangered

Trend: Decreasing ↓

Physical Characteristics

Attribute	Atlantic Gray Seal	Great Hammerhead
Diet	—	Carnivore
Average Lifespan	—	40 years
Average Length	—	5.0 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Atlantic Gray Seal

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Distributed across Belgium, Denmark, Norway, Portugal, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Great Hammerhead

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and flooded grasslands and savannas, among 5 distinct biome types spanning the Indomalayan and Neotropic and Oceanian realms. Populations are also found in montane and highland environments at higher elevations.

Range

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

Atlantic Gray Seal

The Atlantic Gray Seal (Halichoerus grypus) is a species in the genus Halichoerus. It is currently classified as Vulnerable on the IUCN Red List. Typically found in diverse terrestrial and aquatic ecosystems.

Great Hammerhead

The largest hammerhead shark species, great hammerheads reach up to 6 meters and are found in tropical and subtropical coastal waters worldwide. Their distinctive T-shaped head (cephalofoil) dramatically increases sensory surface area for electroreception, enabling them to detect buried stingrays through sand with exceptional precision — stingrays are a preferred prey. Critically Endangered, with populations declining dramatically due to highly valued fins and bycatch mortality.