Brittle Bladderfern vs Common Seal

Cystopteris tenuis compared with Phoca vitulina

Key Differences

• Brittle Bladderfern is Not Evaluated while Common Seal is Near Threatened.

Taxonomic Classification

Rank	Brittle Bladderfern	Common Seal
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Tracheophyta	Chordata (Chordates)
Class	Polypodiopsida (Polypodiopsida)	Mammalia (Mammals)
Order	Polypodiales (Polypodiales)	Pinnipedia (Seals & Sea Lions)
Family	Cystopteridaceae	Phocidae (True Seals)
Genus	Cystopteris	Phoca (Harbor Seals)
Species	Cystopteris tenuis	Phoca vitulina

Conservation Status

Brittle Bladderfern

NE — Not Evaluated

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Physical Characteristics

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

Habitat & Geographic Range

Brittle Bladderfern

Habitat

Typically found in moist, shaded forest floors and tropical canopies.

Range

Distributed across Canada and United States.

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.

Brittle Bladderfern

The Brittle Bladderfern (Cystopteris tenuis) is a species in the genus Cystopteris. Typically found in moist, shaded forest floors and tropical canopies.

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:

🇺🇸 United States