Basking shark vs Common Seal

Rhincodon typus compared with Phoca vitulina

Key Differences

• Basking shark is Endangered while Common Seal is Near Threatened.
• Basking shark is omnivore while Common Seal is carnivore.
• Basking shark is 250.0x heavier than Common Seal.
• Basking shark lives longer (100 years vs 30 years).

Taxonomic Classification

Rank	Basking shark	Common Seal
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Chondrichthyes (Cartilaginous Fish)	Mammalia (Mammals)
Order	Lamniformes (Mackerel Sharks)	Pinnipedia (Seals & Sea Lions)
Family	Rhincodontidae (Whale Sharks)	Phocidae (True Seals)
Genus	Rhincodon (Whale Sharks)	Phoca (Harbor Seals)
Species	Rhincodon typus	Phoca vitulina

Evolutionary Relationship

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

Conservation Status

Basking shark

EN — Endangered

Trend: Decreasing ↓

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Physical Characteristics

Attribute	Basking shark	Common Seal
Diet	Omnivore	Carnivore
Average Lifespan	100 years	30 years
Average Length	12.0 m	1.7 m
Average Weight	20.0 t	80.0 kg

Habitat & Geographic Range

Basking shark

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate grasslands and steppes, and montane grasslands and shrublands, among 5 distinct biome types within the Neotropic biogeographic realm.

Range

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

Basking shark

The world's largest fish, whale sharks can exceed 12 meters and 20 tonnes, inhabiting tropical and warm temperate oceans worldwide. Despite their massive size, they are harmless filter feeders, consuming plankton, fish eggs, and small fish by swimming open-mouthed through prey-dense water. They undertake vast seasonal migrations following plankton blooms. Endangered due to fishing, boat strikes, and the live fin trade, with population declining by approximately 50% over the past 75 years.

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 1 countries:

🇵🇹 Portugal