closed-sheathed cottongrass vs Polar bear

Eriophorum brachyantherum compared with Ursus maritimus

Taxonomic Classification

Rank	closed-sheathed cottongrass	Polar bear
Kingdom	Plantae (植物)	Animalia (動物)
Phylum	Magnoliophyta (被子植物門)	Chordata (脊索動物)
Class	Liliopsida (単子葉植物綱)	Mammalia (哺乳類)
Order	Poales (イネ目)	Carnivora (ネコ目)
Family	Cyperaceae	Ursidae (Bears)
Genus	Eriophorum	Ursus (Bears)
Species	Eriophorum brachyantherum	Ursus maritimus

Conservation Status

closed-sheathed cottongrass

VU — Vulnerable

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

closed-sheathed cottongrass

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Distributed across Canada, Norway, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

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.

closed-sheathed cottongrass

Closed-sheathed cottongrass is a sedge in the genus Eriophorum (family Cyperaceae) characterized by leaf sheaths that are fused to form a closed tube around the stem, a morphological feature distinguishing it from open-sheathed relatives. Cottongrasses are quintessential plants of northern peatlands, bogs, and acidic fens across the boreal and arctic zones of the Northern Hemisphere, producing conspicuous cottony white seed heads — modified perianth bristles elongating as fruits mature — that transform peat bogs into spectacular white-tufted landscapes in late spring and early summer. These plants are ecological keystones of Sphagnum-dominated peat bogs, contributing organic matter through their dense root systems that resist decomposition in waterlogged, oxygen-depleted conditions, driving peat formation over millennia. Eriophorum species serve as important food plants for ptarmigan, geese, and various invertebrates in arctic and subarctic ecosystems. Climate change threatens cottongrass habitats through warmer temperatures accelerating peat decomposition, altered hydrological regimes, and permafrost thaw that fundamentally transforms the structure of northern peatlands.

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。