vs Polar bear

Coelosphaerium dubium compared with Ursus maritimus

Key Differences

is Not Evaluated while Polar bear is Vulnerable.

Taxonomic Classification

Rank		Polar bear
Kingdom	Bacteria (Bacteria)	Animalia (動物)
Phylum	Cyanobacteria (藍藻)	Chordata (脊索動物)
Class	Cyanobacteriia	Mammalia (哺乳類)
Order	Cyanobacteriales	Carnivora (ネコ目)
Family	Microcystaceae	Ursidae (Bears)
Genus	Coelosphaerium	Ursus (Bears)
Species	Coelosphaerium dubium	Ursus maritimus

Conservation Status

NE — Not Evaluated

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute		Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Habitat

Native to Asia and Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Sweden, and Taiwan.

Polar bear

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.

Coelosphaerium dubium is a colonial planktonic cyanobacterium in the family Merismopediaceae, named for the taxonomic uncertainty surrounding its morphological boundaries with related species in the genus. Like its congeners, it forms spherical, gelatinous mucilaginous colonies in which cells are distributed at the periphery of a central hyaline matrix. The genus Coelosphaerium has historically been defined by gross morphological characteristics—colony shape, cell arrangement, and mucilage properties—but molecular phylogenetic analyses have substantially revised understanding of cyanobacterial diversity and systematics within this group. Coelosphaerium dubium has a relatively broad geographic distribution compared to some congeners, with records from freshwater bodies in Denmark, Norway, Sweden, and Taiwan, suggesting either a wide ecological tolerance or cryptic species diversity within the taxon. It inhabits lentic and slow-flowing freshwater environments, particularly stratified lakes and ponds where thermal and chemical gradients allow cyanobacterial cells equipped with gas vesicles to adjust their buoyancy and optimise light exposure. As a primary producer in these aquatic ecosystems, it contributes to nutrient cycling and forms part of the phytoplankton community grazed by zooplankton. No formal conservation assessment has been undertaken for this species by the IUCN.

Polar bear

地球上で最大の陸上肉食動物であるホッキョクグマは700kgを超えることがあり、カナダからロシアまでの北極海氷域全体に分布する。ワモンアザラシとヒゲアザラシを狩るために海氷に依存する高度に特化した海洋哺乳類である。広大な距離を泳ぐことができる優れた泳者でもある。脆弱種に指定されており、気候変動による急激な北極海氷の消失で個体群が深刻な圧力を受けている。