Cigar shark vs Green Sea Turtle

Isistius brasiliensis compared with Chelonia mydas

Key Differences

• Cigar shark is Least Concern while Green Sea Turtle is Endangered.

Taxonomic Classification

Rank	Cigar shark	Green Sea Turtle
Kingdom same	Animalia (животные)	Animalia (животные)
Phylum same	Chordata (хордовые)	Chordata (хордовые)
Class	Elasmobranchii	Reptilia (пресмыкающиеся)
Order	Squaliformes (катранообразные)	Testudines (черепахи)
Family	Dalatiidae	Cheloniidae (Sea Turtles)
Genus	Isistius	Chelonia (Green Sea Turtles)
Species	Isistius brasiliensis	Chelonia mydas

Evolutionary Relationship

Cigar shark and Green Sea Turtle share a common ancestor at the Phylum level: Chordata. (хордовые)

Conservation Status

Cigar shark

LC — Least Concern

Green Sea Turtle

EN — Endangered

Population: ~85.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	Cigar shark	Green Sea Turtle
Diet	—	Herbivore
Average Lifespan	—	80 years
Average Length	—	1.2 m
Average Weight	—	200.0 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.

Green Sea Turtle

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 8 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Australia, Brazil, Costa Rica, Indonesia, and Mexico. Currently classified as Endangered 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.

Green Sea Turtle

The green sea turtle is one of the largest sea turtles. They are named for the green color of their cartilage and fat, not their shells.