Cookiecutter Shark Identification Guide

Key identification features

• Small, cigar-shaped body rarely exceeding 50 cm (20 in)
• Uniform brown body with a distinctive dark brown to black collar band around the throat and gill region
• Bioluminescent green underside that glows in deep water, aiding camouflage from below
• Large, round eyes and a short, blunt snout
• Small, low dorsal fins and a rounded caudal fin

Common look-alikes

• False catshark: much larger and lacks both the dark throat collar and the bioluminescent underside.
• Largetooth cookiecutter shark: nearly identical body plan and collar marking, distinguished mainly by a proportionally larger mouth and teeth, and typically a more restricted range.
• Pygmy shark: similarly small and dark but lacks the Cookiecutter's dark collar band.

Where you'll see one

Cookiecutter Sharks live in open tropical and warm temperate oceanic waters worldwide, migrating vertically each day from deep water (down to 3,700 m) to near the surface at night, and are rarely encountered directly except through the distinctive round bite wounds they leave on larger animals.