common hydra vs Common Seal

Hydra vulgaris compared with Phoca vitulina

Key Differences

• common hydra is Not Evaluated while Common Seal is Near Threatened.

Taxonomic Classification

Rank	common hydra	Common Seal
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Cnidaria (Cnidarians)	Chordata (Chordates)
Class	Hydrozoa (Hydrozoa)	Mammalia (Mammals)
Order	Anthoathecata (Anthoathecata)	Pinnipedia (Seals & Sea Lions)
Family	Hydridae	Phocidae (True Seals)
Genus	Hydra	Phoca (Harbor Seals)
Species	Hydra vulgaris	Phoca vitulina

Evolutionary Relationship

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

Conservation Status

common hydra

NE — Not Evaluated

Common Seal

NT — Near Threatened

Population: ~500.0K

Trend: Stable →

Physical Characteristics

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

Habitat & Geographic Range

common hydra

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden.

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.

common hydra

<em>Hydra vulgaris</em>, commonly known as the common hydra, is a small freshwater cnidarian in the family Hydridae. Its conservation status has not been formally evaluated by the IUCN. The species is recorded from Denmark, Norway, and Sweden, with its native range understood to encompass Europe broadly. It typically inhabits slow-moving or still freshwater bodies such as ponds, lakes, and streams, where it attaches to aquatic vegetation or submerged substrates. The common hydra is notable for its remarkable regenerative capabilities and has been the subject of substantial biological research. Diet information for this species is not available in current records. Biological traits of this species remain poorly documented in the scientific literature.

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 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden