coastal arrow worm vs Oso Polar

Parasagitta setosa compared with Ursus maritimus

Key Differences

• coastal arrow worm is Not Evaluated while Oso Polar is Vulnerable.

Taxonomic Classification

Rank	coastal arrow worm	Oso Polar
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chaetognatha (gusanos flecha)	Chordata (cordados)
Class	Sagittoidea (Sagittoidea)	Mammalia (mamíferos)
Order	Aphragmophora (Aphragmophora)	Carnivora (carnívoros)
Family	Sagittidae	Ursidae (Bears)
Genus	Parasagitta	Ursus (Bears)
Species	Parasagitta setosa	Ursus maritimus

Evolutionary Relationship

coastal arrow worm and Oso Polar share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

coastal arrow worm

NE — Not Evaluated

Oso Polar

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	coastal arrow worm	Oso Polar
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

coastal arrow worm

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Russia.

Oso Polar

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

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.

Oso Polar

El mayor carnivoro terrestre de la Tierra, el oso polar puede superar los 700 kg y se encuentra en el hielo marino del Artico, desde Canada hasta Rusia. Es un mamifero marino altamente especializado que depende del hielo marino para cazar focas anilladas y barbadas. Excelente nadador capaz de cubrir grandes distancias en agua abierta. Clasificado como Vulnerable, sus poblaciones soportan una presion severa por la rapida perdida de hielo marino artico debida al cambio climatico.

Shared Countries

Both species can be found in 1 countries:

🇳🇴 Norway