Brown Booby vs Common Seal

Sula leucogaster compared with Phoca vitulina

Key Differences

• Brown Booby is Least Concern while Common Seal is Near Threatened.

Taxonomic Classification

Rank	Brown Booby	Common Seal
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Aves (Birds)	Mammalia (Mammals)
Order	Suliformes (Suliformes)	Pinnipedia (Seals & Sea Lions)
Family	Sulidae	Phocidae (True Seals)
Genus	Sula	Phoca (Harbor Seals)
Species	Sula leucogaster	Phoca vitulina

Evolutionary Relationship

Brown Booby and Common Seal share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Brown Booby

LC — Least Concern

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Physical Characteristics

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

Habitat & Geographic Range

Brown Booby

Habitat

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

Range

Widely distributed across Europe (Denmark, Norway, Sweden), North America (United States), and South America (Colombia, Ecuador, Venezuela).

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.

Brown Booby

Brown Booby (Sula leucogaster) is classified as Least Concern (LC) on the IUCN Red List. Widespread and abundant across its range, with stable populations and no immediate conservation concerns.

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:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden 🇺🇸 United States