Squalelet féroce vs Squalelet dentu

Isistius brasiliensis compared with Isistius plutodus

Taxonomic Classification

Rank	Squalelet féroce	Squalelet dentu
Kingdom same	Animalia (animal)	Animalia (animal)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class same	Elasmobranchii	Elasmobranchii
Order same	Squaliformes (Squaliformes)	Squaliformes (Squaliformes)
Family same	Dalatiidae	Dalatiidae
Genus same	Isistius	Isistius
Species	Isistius brasiliensis	Isistius plutodus

Evolutionary Relationship

Squalelet féroce and Squalelet dentu share a common ancestor at the Genus level: Isistius.

Conservation Status

Squalelet féroce

LC — Least Concern

Squalelet dentu

LC — Least Concern

Physical Characteristics

Attribute	Squalelet féroce	Squalelet dentu
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Squalelet féroce

Habitat

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

Range

Distributed across Chile, Norway, and Taiwan.

Squalelet dentu

Squalelet féroce

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.