Common Earthball vs Polar bear

Scleroderma citrinum compared with Ursus maritimus

Key Differences

Common Earthball is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Earthball	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	Boletales (イグチ目)	Carnivora (ネコ目)
Family	Sclerodermataceae	Ursidae (Bears)
Genus	Scleroderma	Ursus (Bears)
Species	Scleroderma citrinum	Ursus maritimus

Conservation Status

Common Earthball

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Common Earthball

Habitat

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

Range

Widely distributed across Asia (Taiwan), Europe (5 countries), North America (United States), and South America (Brazil, Chile).

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 Earthball

Scleroderma citrinum, commonly known as the common earthball or pigskin poison puffball, is a widespread ectomycorrhizal fungus in the family Sclerodermataceae, classified as Least Concern by the IUCN. The species occurs across Asia, Europe, North America, and South America, typically found on forest floors, decomposing wood, and mineral-rich acidic soils in association with hardwood and conifer tree roots. Unlike true puffballs, Scleroderma citrinum is considered poisonous and should not be confused with edible species. Its thick, warty outer skin ranges from yellowish-brown to ochre and encloses a dark purplish-black spore mass that matures over time. The species plays an important ecological role as a mycorrhizal partner, forming mutualistic associations with the roots of oaks, beeches, pines, and other trees, facilitating the uptake of water and nutrients by host plants in exchange for photosynthetically derived carbon. Fruiting bodies typically emerge from late summer through autumn, releasing spores through irregular cracks or a central apical opening when mature. Scleroderma citrinum is a host for the parasitic fungus Pseudoboletus parasiticus, making it ecologically significant within forest fungal communities. Biological traits of this species remain poorly documented in the scientific literature.

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。