Species page
Cookiecutter Shark
Small shark that carves neat circular bites from larger animals.
Isistius brasiliensis
Least concern
Overview
This species belongs to a deepwater-oceanic family that includes the luminous cookiecutter and kitefin sharks. Treat the profile as a provisional guide to small, dark, often poorly seen sharks of the dim midwater world. Dalatiids are usually small to medium sharks with no anal fin, two spineless dorsal fins, and in many species a dark body adapted to deep or open-ocean life. Several species also have light-producing organs. Kitefin, cookiecutter, and related sharks occur in tropical to temperate seas around the world, mainly in oceanic or deepwater settings. Many species have broad but thinly sampled distributions.
This family is most often associated with mesopelagic waters, deep slopes, and offshore environments. Some species make nightly movements toward the surface.
A notorious tiny shark with outsized reputation.
Why it matters: Some dalatiids glow, helping them blend into faint downwelling light from above.
Scientific nameIsistius brasiliensis
FamilyDalatiidae
OrderSqualiformes
Max length0.6 m
Depth range85 to 3500 meters
ConservationLeast concern
RegionWarm oceanic waters worldwide
DietFish, squid, and tissue from larger animals
HabitatOpen ocean, often deep by day
Why it stands outCircular biting strategy
What this shark is
Dalatiids are usually small to medium sharks with no anal fin, two spineless dorsal fins, and in many species a dark body adapted to deep or open-ocean life. Several species also have light-producing organs.
Where it lives
Kitefin, cookiecutter, and related sharks occur in tropical to temperate seas around the world, mainly in oceanic or deepwater settings. Many species have broad but thinly sampled distributions.
This family is most often associated with mesopelagic waters, deep slopes, and offshore environments. Some species make nightly movements toward the surface.
How it differs from similar sharks
Circular biting strategy
Compare it against γ³γγ¬γγ«γγΆγ‘, Blacknose Shark, and Bonnethead.
Why it is notable
People rarely meet them alive. Most human relevance comes from unusual bite marks on prey, bycatch, or occasional records from deepwater fisheries.
Related shark pages
These links are meant to help readers continue through related species, not force extra clicks.
γ³γγ¬γγ«γγΆγ‘
Common name: Largetooth cookiecutter shark
This species belongs to a deepwater-oceanic family that includes the luminous cookiecutter and kitefin sharks. Treat the profile as a provisional guide to small, dark, often poorly seen sharks of the dim midwater world.
0.4 m max
Blacknose Shark
Small coastal shark with a raised dorsal 'blacknose' profile.
2.0 m maxEndangered
Bonnethead
Small hammerhead with a rounded head and quick turns.
1.7 m maxLeast Concern