vs Polar bear

Ciboria betulae compared with Ursus maritimus

Key Differences

is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank		Polar bear
Kingdom	Fungi (菌界)	Animalia (動物)
Phylum	Ascomycota (子嚢菌門)	Chordata (脊索動物)
Class	Leotiomycetes (Leotiomycetes)	Mammalia (哺乳類)
Order	Helotiales (Helotiales)	Carnivora (ネコ目)
Family	Sclerotiniaceae	Ursidae (Bears)
Genus	Ciboria	Ursus (Bears)
Species	Ciboria betulae	Ursus maritimus

Conservation Status

LC — Least Concern

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 Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Denmark, Norway, 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.

Ciboria betulae is a small discomycete fungus in the family Sclerotiniaceae, associated with birch (Betula) trees across temperate Europe and northern Asia. The species fruits on fallen birch catkins, seeds, or occasionally on decaying birch wood in moist woodland habitats and riparian zones. Its fruiting bodies are typical of the genus: small, stalked cup fungi with a pale to medium brown, concave disc surface. Ciboria betulae is saprotrophic, breaking down plant debris and contributing to nutrient cycling in birch woodland ecosystems. The species name clearly references its host association with Betula. It is classified as Least Concern, reflecting a distribution that is wide, though perhaps locally patchy, across birch-dominated forests and woodland edges. Birch catkins provide a specific substrate window in late spring and early summer after they fall, meaning the fruiting season of this species is typically brief and easily missed. Microscopic features including ascospore dimensions and shape, paraphysis morphology, and excipular tissue help differentiate Ciboria betulae from closely related species on other substrates. The genus Ciboria encompasses multiple species each associated with particular plant substrates, representing a degree of substrate specialization unusual among saprotrophic cup fungi. Records are scattered but consistent across the temperate birch belt of Eurasia.

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。