Largetooth Cookiecutter Shark

The Largetooth Cookiecutter shark belongs to the family of cookiecutter or cigar sharks. It gets its name from its extremely long lower teeth, which are the largest compared to the body size of any shark. It has several common names, such as longtooth or bigtooth cookiecutter shark and the Gulf dogfish. It bears a close resemblance to the Smalltooth cookiecutter shark. Still, it differs in the size and number of teeth, markings, and fin placement.

The first description of this species was given in 1964 by Jack Garrett and Stewart Springer, based on an adult female caught near Mexico. Only ten specimens have been caught and studied; hence little information is available about them.

Largetooth Cookiecutter Shark Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Chondrichthyes
Order Squaliformes
Family Dalatiidae
Genus Isistius
Scientific name I. plutodus


This shark can grow up to 42 cm (16.5 in). It has a long, cigar-shaped body with a distinctively blunt, short head and snout. Its massive, forward-facing oval eyes allow for binocular vision. It has five pairs of small gill slits.

Their bodies are dark brown with light-emitting photophores scattered across the belly. However, few specimens lacked the distinct black collar found in the other species. They have transverse, gaping mouths with fleshy suctorial lips. However, compared to the smalltooth species, the largetooth cookiecutter has a stronger jaw and fewer rows of teeth. There are 29 and 19 rows of teeth in the upper and lower jaw, respectively. The upper teeth are small, smooth, and angled towards the center. The lower teeth are enormous, triangular, and serrated.

The pectoral fins are small, rounded, and placed high on the body behind the gill slits. The dorsal fins are placed far back, with the first dorsal fin located just ahead of the tiny pelvic fins and the second just behind. The tail fin is very short, with an upper lobe twice as long as the lower and a prominent notch near the tip. The anal fin is absent.

Where do they live

Map Of The Largetooth Cookiecutter Shark’s Habitat

Largetooth Cookiecutter Shark Habitat Map

The ten known specimens were caught in a variety of widely scattered locations. They were found off Alabama in the United States, near Bahia in Brazil, the Azores, and Western Sahara in the Atlantic Ocean. They were also caught near Okinawa, Japan, and New South Wales in the Pacific. They inhabit the epipelagic zone at a depth of 60-200 m (200-660 ft) over continental shelves and slopes. They also frequent continental trenches as deep as 6.44 km (4 mi).



This species is an ectoparasite. It feeds by biting off chunks of animals like bony fishes, squid, other sharks, and marine mammals.


This fish hunts with its fleshy lips and huge teeth to latch onto its prey. It employs a sweeping motion to gouge out a large, oval wound with parallel grooves, hence the name cookiecutter. It often attacks the flank and is known to cause the deaths of its targets by leaving them stranded. According to studies, this species is responsible for up to 80% of cookiecutter attacks on cetaceans in Brazilian waters.


Researchers assume that this species follows an ovoviviparous mode of reproduction. Its life cycle and size of litter are unknown.


They are very weak swimmers, as evidenced by their small rear fins. A huge oil-filled liver occupies much of their body cavity, allowing them to float in the water with little effort.

The bioluminescent photophores on their belly are thought to be used for camouflage and attracting prey. Their binocular vision also helps them target their attacks more precisely.

Human interactions

Due to its deepwater habitat, this species is unimportant to commercial fisheries. It has mostly been caught as bycatch by longlines and trawlers.

The IUCN has listed this shark as “Least Concern” or “LC.”

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