The Cookiecutter Shark

  The cookiecutter shark is a small shark which inhabits deep waters. It can grow up to fifty centimetres in length and spends the day at depths of up to 3,570 metres below the surface. They rise to the surface at night, where they hunt their prey. It is rather hard to imagine what prey a minuscule shark such as this could hope to catch at the surface of the open ocean. Most Sunlight zone creatures are larger animals than those of the Twilight and Trench zones. The few small fish species there are do not often stray into the open ocean. However, the cookiecutter shark has developed a hunting technique so sophisticated, it is hard to believe it is true.
  The cookiecutter shark has an unusually rounded jaw for a shark. The reason for this is its hunting technique. Using its bioluminescent body, the cookiecutter shark attracts other sea creatures to it. These creatures are, more often than not, dolphins, sailfish and whales. As the animal passes by, the diminutive shark uses its jaw to latch on. it then swims in a circle until it tears away a cookie-sized piece of its victims tissue. Hence the name, cookiecutter.
  Due to the fact they only come into humanly accessible waters at night, cookiecutters are rarely encountered by people. However, using cameras, they have been monitored by biologists, which is how we first learnt of their feeding method. Cookiecutter attacks on people are extremely uncommon, both for the reason above and the fact that humans have less blubber than dolphins and other creatures they prey on.
 

A cookiecutter shark examining a diver's camera.

The range of the cookiecutter shark.

The unusually rounded jaw of a cookiecutter shark.

A cookiecutter shark bite on a yellowfin tuna.