Cigar shark vs Gray-footed Spiny-rat

Isistius brasiliensis compared with Proechimys poliopus

Key Differences

• Cigar shark is Least Concern while Gray-footed Spiny-rat is Vulnerable.

Taxonomic Classification

Rank	Cigar shark	Gray-footed Spiny-rat
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Elasmobranchii	Mammalia (Mammals)
Order	Squaliformes (Squaliformes)	Rodentia (Rodents)
Family	Dalatiidae	Echimyidae
Genus	Isistius	Proechimys
Species	Isistius brasiliensis	Proechimys poliopus

Evolutionary Relationship

Cigar shark and Gray-footed Spiny-rat share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Cigar shark

LC — Least Concern

Gray-footed Spiny-rat

VU — Vulnerable

Physical Characteristics

Attribute	Cigar shark	Gray-footed Spiny-rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

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.

Gray-footed Spiny-rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Found in Venezuela. 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.