Weird Ones | The Cookiecutter shark
A cookiecutter shark (Isistius brasiliensis) may be one of the smallest of sharks and have a cartoon-style name, but this tiny predator is far from fun and cuddly
Small, cigar-shaped body, which is dark brown on top and light brown at the belly. Big, triangular teeth in the lower jaw and small, piercing teeth in the upper jaw.
Males reach up to 42cm in length, while the larger females can grow as long as 56cm.
Western and Eastern Atlantic, Indo-Pacific and Eastern Pacific. Found as deep as 3,500m.
NEED TO KNOW
A cookiecutter shark may be one a relatively small shark, but is a fierce and ruthless predator. It is named after the neat biscuit-shaped wounds it leaves on the bodies of larger fish and marine mammals during a feeding attack.
Also known as a ‘cigar’ shark because of its shape, it travels below 1,000m during daylight hours and cruises up to the surface by night in tropical waters worldwide. It grows no longer than 50cm, but this does not deter it from picking on the big stuff when feeding, including large fish, whales, squid and even dolphins.
The cookiecutter attaches its mouth to its prey using strong suction, then spins itself around. The shark’s lower teeth then bite out chunks before it swims away leaving a perfectly circular, deep flesh wound in its victims.
This brown, wide-eyed predator has a blunt snout, with a dorsal fin that is small and closer to its tail than with most sharks. The large eyes have green pupils and the belly has a small patch of bioluminescence used to lure prey to the deep. The bioluminescent patch looks like a bite-size meal to hunting fish. Once a would-be hunter is lulled into a false sense of security, the cookiecutter ambushes it.
Despite its bloody eating habits, the cookiecutter shark is not considered dangerous to humans, as it is small and lives in deep water. Bizarrely, however, there are reports of this species leaving crater-like marks on the sonar domes of nuclear submarines – a real-life cookie monster!