白头海雕 vs common hydra

Haliaeetus leucocephalus compared with Hydra vulgaris

Taxonomic Classification

Rank	白头海雕	common hydra
Kingdom same	Animalia (动物界)	Animalia (动物界)
Phylum	Chordata (脊索动物门)	Cnidaria (刺胞動物門)
Class	Aves (鳥綱)	Hydrozoa (水螅纲)
Order	Accipitriformes (鷹形目)	Anthoathecata (花水母目)
Family	Accipitridae (Hawks & Eagles)	Hydridae
Genus	Haliaeetus (Sea Eagles)	Hydra
Species	Haliaeetus leucocephalus	Hydra vulgaris

Evolutionary Relationship

白头海雕 and common hydra share a common ancestor at the Kingdom level: Animalia. (动物界)

Conservation Status

白头海雕

NE — Not Evaluated

Population: ~316.7K

Trend: Increasing ↑

common hydra

NE — Not Evaluated

Physical Characteristics

Attribute	白头海雕	common hydra
Diet	Carnivore	—
Average Lifespan	28 years	—
Average Length	90 cm	—
Average Weight	5.0 kg	—

Habitat & Geographic Range

白头海雕

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and flooded grasslands and savannas, among 10 distinct biome types spanning the Neotropic and Palearctic realms. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Europe (8 countries), North America (United States), and South America (Ecuador).

common hydra

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden.

白头海雕

白头海雕是美国国鸟，也是美国生态保护史上的成功案例，曾因滴滴涕（DDT）的广泛使用而濒临灭绝，经保护措施的实施后种群数量已显著恢复。该物种在IUCN红色名录中被评估为无危（LC），以白色头颈和尾羽与深棕色体羽形成的鲜明对比为主要识别特征。它们主要以鱼类为食，也会捕食哺乳动物和腐肉。

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.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden