Cookiecutter shark

The cookiecutter shark, also known as the cigar shark, is a small yet fascinating species of squaliform shark inhabiting warm oceanic waters worldwide. Found at depths of up to 3.7 kilometers, these sharks perform astounding daily vertical migrations, ascending as much as 3 kilometers closer to the surface each night.

What is particularly captivating about the cookiecutter shark is its unique feeding habit. It creates round, cookie-cutter-like wounds by excising plugs of flesh from larger animals. These distinctive marks can be observed on a variety of marine mammals, fish, and even on submarines and humans. The shark's hunting tactics are equally remarkable, relying on stealth and deception. It uses a dark collar to mimic the silhouette of a smaller fish and employs bioluminescence to lure unsuspecting prey.

First described by French naturalists in the early 19th century, the cookiecutter shark has been extensively studied since. It has a distinctive appearance, featuring a cylindrical body, large eyes, and specialized teeth suited for its parasitic lifestyle. While it has been known to attack humans, such incidents are rare, and the shark is not considered a significant threat. In fact, the International Union for Conservation of Nature classifies it as of least concern.

These sharks thrive in tropical and warm-temperate waters, preferring temperatures between 18-26°C. They adhere to a daily pattern known as diel vertical migration, spending daylight hours in the deep and ascending at night. They target a variety of oceanic animals, leaving their telltale circular wounds. Their feeding strategy involves creating a suction seal on their prey before using their specialized teeth to carve out a chunk of flesh.

Reproduction in cookiecutter sharks involves aplacental viviparity, meaning they give birth to live young without a placental connection. Litters typically consist of 6-12 pups. These sharks may also travel in schools, likely aiding in more effective feeding and avoiding larger predators.

While encounters with humans are infrequent, the cookiecutter shark has been known to attack swimmers on rare occasions and can inflict damage on submarines, fishing nets, and oceanographic equipment due to its feeding behavior.