白头海雕 vs coastal arrow worm

Haliaeetus leucocephalus compared with Parasagitta setosa

Taxonomic Classification

Rank	白头海雕	coastal arrow worm
Kingdom same	Animalia (动物界)	Animalia (动物界)
Phylum	Chordata (脊索动物门)	Chaetognatha (毛颚动物门)
Class	Aves (鳥綱)	Sagittoidea (箭虫纲)
Order	Accipitriformes (鷹形目)	Aphragmophora (无横肌目)
Family	Accipitridae (Hawks & Eagles)	Sagittidae
Genus	Haliaeetus (Sea Eagles)	Parasagitta
Species	Haliaeetus leucocephalus	Parasagitta setosa

Evolutionary Relationship

白头海雕 and coastal arrow worm 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 ↑

coastal arrow worm

NE — Not Evaluated

Physical Characteristics

Attribute	白头海雕	coastal arrow worm
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).

coastal arrow worm

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Russia.

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。

coastal arrow worm

Parasagitta setosa, the coastal arrow worm, is a chaetognath in the family Sagittidae inhabiting the coastal and neritic waters of the northeastern Atlantic Ocean and adjacent North Sea and Baltic Sea, with confirmed records from Denmark, Norway, and Russia. Arrow worms are small, transparent, torpedo-shaped marine invertebrates typically 1–5 centimeters long, and despite their common name, are neither worms nor closely related to any familiar animal group; they form their own phylum, Chaetognatha, comprising around 120 species. Parasagitta setosa is a predatory planktonic species, using stiff bristle-like grasping spines flanking its mouth to seize copepods, small fish larvae, and other zooplankton that form the bulk of its diet. It occupies neritic plankton communities, often occurring in brackish coastal waters and estuaries where many arrow worm species cannot tolerate reduced salinity. The species serves as an important prey item for fish including herring and sprat and functions as a significant link in coastal marine food webs. Arrow worm phylogenetic position has been debated extensively; molecular evidence places them near the base of protostome animals. The species is Not Evaluated by the IUCN, as marine zooplankton populations are rarely assessed due to monitoring challenges.

Shared Countries

Both species can be found in 2 countries:

🇩🇰 Denmark 🇳🇴 Norway