cinereus shrew vs Polar bear

Sorex cinereus compared with Ursus maritimus

Key Differences

• cinereus shrew is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	cinereus shrew	Polar bear
Kingdom same	Animalia (动物界)	Animalia (动物界)
Phylum same	Chordata (脊索动物门)	Chordata (脊索动物门)
Class same	Mammalia (哺乳動物)	Mammalia (哺乳動物)
Order	Soricomorpha (鼩形目)	Carnivora (食肉目)
Family	Soricidae	Ursidae (Bears)
Genus	Sorex	Ursus (Bears)
Species	Sorex cinereus	Ursus maritimus

Evolutionary Relationship

cinereus shrew and Polar bear share a common ancestor at the Class level: Mammalia. (哺乳動物)

Conservation Status

cinereus shrew

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

cinereus shrew

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Found in United States.

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.

cinereus shrew

The cinereus shrew (Sorex cinereus), also known as the masked shrew, is a small insectivorous mammal in the family Soricidae, native to North America. It has one of the widest distributions of any North American shrew, ranging from Alaska and Canada south through the northern United States, with isolated populations in the Appalachian Mountains and Rocky Mountains. It inhabits a broad range of habitats including moist forest, meadows, bogs, marshes, and brushy areas, where it hunts continuously for insects, earthworms, small vertebrates, fungi, and carrion to fuel its extremely rapid metabolism. Like all shrews, the cinereus shrew has a very high metabolic rate and must consume almost its own body weight in food daily. It is tiny—typically 3–5 grams—with dense gray-brown fur. The species is classified as Least Concern by the IUCN, with abundant and widespread populations across the boreal and northern temperate zones. It is a major component of small mammal communities in northern forests and plays an important role in food webs as prey for owls, hawks, and weasels. The species reproduces rapidly, with multiple litters per year, helping sustain populations despite high predation pressure. It is entirely North American and does not occur in Europe.

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。