Cookiecutter Shark

The cookiecutter shark is a small, deep-water shark in the family Dalatiidae, best known for removing circular plugs of flesh from larger animals.

The cookiecutter shark (Isistius brasiliensis), also known as the cigar shark, is a small, deep-water shark in the family Dalatiidae. It is best known for removing circular plugs of flesh from larger animals, leaving distinctive round wounds. Despite its feeding habits, it is generally considered harmless to humans because of its small size and offshore habitat.

Description

The cookiecutter shark is a small squaliform shark with a cigar-shaped body, typically reaching about 42–56 cm in length. It has a dark coloration with a lighter underside and a distinctive glowing belly due to bioluminescent organs. Its lower teeth are specialized for carving circular wounds, while its upper teeth are smaller and used for gripping.

Behaviour and feeding

The cookiecutter shark feeds on small prey such as squid, as well as on tissue from larger animals including fish and marine mammals. It attaches to its prey using suction, then twists its body to carve out a neat circular plug of flesh using its lower teeth. This feeding method leaves characteristic cookie-shaped wounds on the prey.

Distribution and habitat

Cookiecutter sharks live in offshore tropical and warm-temperate waters across the Atlantic, Indian, and Pacific oceans. They are associated with deep water and often move vertically in the water column, possibly following prey. They are found in tropical and subtropical waters worldwide.

Taxonomy and conservation

The cookiecutter shark is a member of the family Dalatiidae and is commonly listed as Isistius brasiliensis. The best-known species is Isistius brasiliensis, but there is also the largetooth cookiecutter shark, Isistius plutodus. The species is assessed as Least Concern on the IUCN Red List, reflecting its broad distribution and lack of a major targeted fishery.