Common Seal vs Flat Periwinkle

Phoca vitulina compared with Littorina obtusata

Key Differences

• Common Seal is Near Threatened while Flat Periwinkle is Least Concern.

Taxonomic Classification

Rank	Common Seal	Flat Periwinkle
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chordata (Chordates)	Mollusca (Mollusks)
Class	Mammalia (Mammals)	Gastropoda (Gastropoda)
Order	Pinnipedia (Seals & Sea Lions)	Littorinimorpha (Littorinimorpha)
Family	Phocidae (True Seals)	Littorinidae
Genus	Phoca (Harbor Seals)	Littorina
Species	Phoca vitulina	Littorina obtusata

Evolutionary Relationship

Common Seal and Flat Periwinkle share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Flat Periwinkle

LC — Least Concern

Physical Characteristics

Attribute	Common Seal	Flat Periwinkle
Diet	Carnivore	—
Average Lifespan	30 years	—
Average Length	1.7 m	—
Average Weight	80.0 kg	—

Habitat & Geographic Range

Common Seal

Habitat

Typically found in diverse ecosystems where prey species are available.

Range

Found across Europe (7 countries) and North America (United States). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Flat Periwinkle

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Common Seal

The most widely distributed pinniped, harbor seals inhabit temperate and subarctic coastal waters of both the North Atlantic and North Pacific. Adults reach up to 130 kg and spend roughly equal time at sea hunting fish, squid, and crustaceans and hauling out on beaches or rocks to rest. Their large, expressive eyes are adapted for underwater vision in low light. Harbor seals are a critical food source for orcas, sharks, and polar bears.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden