Cookiecutter shark

 

Sea Zone | Cookiecutter shark | The cookiecutter shark (Isistius brasiliensis), also known as the cigar shark, a species of small dogfish shark in the family Dalatiidae. This shark occurs in warm ocean waters worldwide, especially in the vicinity of islands and is recorded as deep as 3.7 kilometers (2.3 miles). It moves vertically up to 3 km (1.9 miles) every day, approaching the surface at dusk and descending at dawn. Reaching only 42-56 cm (17-22 inches) in length, the cookie cutter shark a long, cylindrical body with a short, blunt snout, large eyes, two tiny spineless dorsal fins and a large tail fin. It is dark brown in color, with light-emitting photophores cover its bottom with the exception of a dark "collar" around his neck and gill slits.

The name cookiecutter shark refers to its feeding habit of gouging round plug, like a cookie cutter, made of larger animals. Marks from cookie cutter sharks have been found made on a variety of marine mammals and fish as well as on submarines, submarine cables and even the human body. It consumes all the smaller prey such as squid. Cookie Cutter Sharks have adaptations for hovering in the water column and probably abandoned on stealth and deception to catch more active prey. His neck seems to be the dark silhouette of a small fish to imitate, while the rest of its body fits into the light downward on its ventral photophores. If a would-be robber approached the bait, the shark puts over his sucking lips and throat specialist and properly excise a piece of meat with his band saw as the lower teeth. This species is known to travel to the schools.

Although rare, because the oceanic habitat encountered a handful of documented attacks on humans were apparently caused by cookie cutter sharks. Nevertheless, this small shark is not considered very dangerous. The International Union for Conservation of Nature (IUCN) has listed the cookie cutter shark at Least Concern because it is widely used, has no commercial value, and is not particularly vulnerable to the fishery.