Cigar shark vs Polar bear

Isistius brasiliensis compared with Ursus maritimus

Key Differences

Cigar shark is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Cigar shark	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	Elasmobranchii	Mammalia (哺乳動物)
Order	Squaliformes (角鲨目)	Carnivora (食肉目)
Family	Dalatiidae	Ursidae (Bears)
Genus	Isistius	Ursus (Bears)
Species	Isistius brasiliensis	Ursus maritimus

Evolutionary Relationship

Cigar shark and Polar bear share a common ancestor at the Phylum level: Chordata. (脊索动物门)

查看 Phylum: Chordata

Conservation Status

Cigar shark

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

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

Habitat & Geographic Range

Cigar shark

Habitat

Native to Asia and Europe and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Chile, Norway, and Taiwan.

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.

Cigar shark

The cigar shark, also known as the cookiecutter shark (Isistius brasiliensis), is a small but remarkable shark in the family Dalatiidae, found throughout warm oceanic waters worldwide in tropical and subtropical latitudes. Reaching only 40–50 centimeters in length, it possesses oversized jaws with large, triangular lower teeth arranged in a saw-like series that cut distinctive circular plugs of flesh from much larger prey—including tuna, dolphins, whales, billfish, and even submarine cables and human bodies. It does not kill its prey but instead latches on, rotates its body, and excises a characteristic cookie-cutter-shaped bite. The cigar shark is bioluminescent, emitting a green glow from photophores on its ventral surface that may serve as counter-illumination or to attract prey from below. It undertakes diel vertical migrations, ascending to shallower waters at night and descending to mesopelagic depths during the day. The species is classified as Least Concern by the IUCN, with a vast oceanic distribution and no targeted commercial fishery. It is occasionally taken as bycatch. The geographic epithet brasiliensis refers to Brazil, where early specimens were described, but the species' range is circumglobal in warm oceans. The cookiecutter shark's feeding strategy is one of the most unusual among elasmobranchs.