- Tube-shaped, the cookiecutter shark's dorsal side is dark in color with a black ring around the gills. A luminescent coating of light-producing organs called photophores covers its underside. A suction-shaped mouth holds small upper teeth and larger lower teeth.
- Living near islands in waters up to 3,500 meters (11,482 feet) deep, cookiecutter sharks range in all oceans. One finds them in the Amazon and Caribbean waters as well, in addition to many others.
- This shark, like others, is a carnivore, feeding on squid, large bony fish and other sharks. Crustaceans also become prey for the solitary species of shark, which only joins with others of its kind for the mating season.
- Cookiecutter sharks bite their prey differently from other sharks by using their suctioned mouth to attach firmly to the chosen prey. The shark then bites down with its teeth interlocked, and pulls the flesh away from the prey by scooping with the lower teeth. The bite leaves a distinctive circular wound in the attacked fish.
- A female cookiecutter, after mating with the male, covers her eggs with a protective rough substance. She then distributes the eggs on rocks and seaweed for hatching. The eggs hatch in 12 to 22 months into fully formed babies already capable of hunting and providing for themselves.
