Common Rough Woodlouse vs Polar bear

Porcellio scaber compared with Ursus maritimus

Key Differences

• Common Rough Woodlouse is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Rough Woodlouse	Polar bear
Kingdom same	Animalia (动物界)	Animalia (动物界)
Phylum	Arthropoda (节肢动物门)	Chordata (脊索动物门)
Class	Malacostraca (软甲纲)	Mammalia (哺乳動物)
Order	Isopoda (等足目)	Carnivora (食肉目)
Family	Porcellionidae	Ursidae (Bears)
Genus	Porcellio	Ursus (Bears)
Species	Porcellio scaber	Ursus maritimus

Evolutionary Relationship

Common Rough Woodlouse and Polar bear share a common ancestor at the Kingdom level: Animalia. (动物界)

Conservation Status

Common Rough Woodlouse

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Common Rough Woodlouse

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and deserts and xeric shrublands within the Indomalayan biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (South Africa), Asia (Japan, Sri Lanka), Europe (5 countries), North America (United States), and South America (Brazil).

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 Rough Woodlouse

<em>Porcellio scaber</em>, the common rough woodlouse, is a terrestrial isopod crustacean in the family Porcellionidae. One of the most widespread and abundant woodlouse species in the world, it has established itself across Europe, the Americas, Asia, Australia, and numerous oceanic islands, including populations documented in Belgium, Brazil, Denmark, Japan, and Norway. This synanthropic species typically inhabits decaying leaf litter, rotting wood, compost heaps, under stones, and in the soil of gardens, forests, and human-modified landscapes. It thrives in moist, sheltered microhabitats and shows some tolerance for drier conditions compared to related species. As a detritivore, the common rough woodlouse feeds primarily on decaying organic matter including leaf litter, rotting wood, fungi, and plant debris, playing a significant role in nutrient cycling and decomposition processes. The species reproduces sexually, with females brooding eggs and juveniles in a specialized brood pouch. Assessed as Least Concern by the IUCN, its cosmopolitan distribution and high adaptability make it one of the most ecologically resilient terrestrial isopods. It is easily identified by its rough, grey to dark brown dorsal surface with pale lateral markings. Biological traits such as average lifespan and typical body length remain variable across populations and are not uniformly documented in standardized databases.

Polar bear

北极熊是地球上最大的陆地食肉动物，体重可超过700千克，分布于从加拿大到俄罗斯的北极海冰区。是高度特化的海洋哺乳动物，依赖海冰捕猎环斑海豹和髯海豹。是优秀的游泳者，能够横渡广阔的开阔水域。被列为易危种，因气候变化导致北极海冰迅速减少，种群正受到严重威胁。

Shared Countries

Both species can be found in 1 countries:

🇳🇴 Norway