Common Rustgill vs Polar bear

Gymnopilus penetrans compared with Ursus maritimus

Key Differences

Common Rustgill is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Rustgill	Polar bear
Kingdom	Fungi (菌界)	Animalia (動物)
Phylum	Basidiomycota (担子菌門)	Chordata (脊索動物)
Class	Agaricomycetes (真正担子菌綱)	Mammalia (哺乳類)
Order	Agaricales (ハラタケ目)	Carnivora (ネコ目)
Family	Hymenogastraceae	Ursidae (Bears)
Genus	Gymnopilus	Ursus (Bears)
Species	Gymnopilus penetrans	Ursus maritimus

Conservation Status

Common Rustgill

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Common Rustgill

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Distributed across Belgium, Denmark, Norway, Portugal, and Sweden.

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.

Common Rustgill

Gymnopilus penetrans, the common rustgill, is a saprotrophic basidiomycete fungus in the family Hymenogastraceae, commonly found across temperate regions of Europe and beyond. It has been recorded in Belgium, Denmark, Norway, Portugal, and Sweden, typically fruiting on decaying conifer wood, stumps, buried roots, and woody debris in forests and woodland habitats. The fruiting bodies are small to medium-sized mushrooms with tawny orange to rust-brown caps, typically 2–7 centimeters in diameter, and bright rusty-orange gills that give the species its common name. The stem is similarly colored and typically fibrous. As a wood-decaying fungus, common rustgill plays an important ecological role in the decomposition of dead conifer timber and the recycling of nutrients in forest ecosystems. The species produces minute, roughened, rusty-brown spores. It is assessed as Least Concern on the IUCN Red List. The common rustgill typically fruits from late summer through autumn. It may occasionally be confused with related Gymnopilus species; some members of the genus contain potentially toxic or psychoactive compounds, though G. penetrans is generally considered of low toxicity. Biological traits such as average lifespan and detailed dietary substrate specificity remain poorly documented in comprehensive ecological databases.

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。