Bladder Fern vs Common Seal

Cystopteris fragilis compared with Phoca vitulina

Key Differences

Bladder Fern is Not Evaluated while Common Seal is Near Threatened.

Taxonomic Classification

Rank	Bladder Fern	Common Seal
Kingdom	Plantae (พืช)	Animalia (สัตว์)
Phylum	Tracheophyta	Chordata (สัตว์มีแกนสันหลัง)
Class	Polypodiopsida (Polypodiopsida)	Mammalia (สัตว์เลี้ยงลูกด้วยน้ำนม)
Order	Polypodiales (Polypodiales)	Pinnipedia (Seals & Sea Lions)
Family	Cystopteridaceae	Phocidae (True Seals)
Genus	Cystopteris	Phoca (Harbor Seals)
Species	Cystopteris fragilis	Phoca vitulina

Conservation Status

Bladder Fern

NE — Not Evaluated

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Physical Characteristics

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

Habitat & Geographic Range

Bladder Fern

Habitat

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

Range

Widely distributed across Asia (Taiwan), Europe (6 countries), North America (Canada, United States), and South America (Colombia).

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.

Bladder Fern

The Bladder Fern (Cystopteris fragilis) is a species in the genus Cystopteris. Typically found in moist, shaded forest floors and tropical canopies.

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.