The cookie cutter shark (Isistius brasiliensis) is also known as the luminous and cigar shark; these sharks live in all over in deep ocean waters, generally 3,300 feet to 11,500 feet and below. They are small sharks, usually only about 20 inches in length with a body shaped like a cigar. They have rather large eyes with green pupils and their small sharp teeth are hidden behind fleshy lips until they are ready to strike. Their bottom teeth are slightly bigger, which is an important factor when it comes to attacking their prey. Cookie cutter sharks have 2 little dorsal fins towards the back of their tail. The belly side of this shark glows a pale blue-green, making it bioluminescent, which camouflages into the ocean. There is, however a small black patch that isn’t luminescent that tricks weaker fish into attacking them, which only results in the cookie cutter shark satisfying its hunger a little more.
Very little information has been retrieved about the details of their reproduction, but it is believed that these cookie cutter sharks are ovoviviparous also called aplacental viviparitious. This method of reproduction occurs when the babies hatch from eggs, in this case they hatch and pups develop inside the mother’s body. Aplacenta means that there is no placenta, which nourishes and passes nutrition to the pups, directly. It is also, believed that they produce about 6-7 pups at a time. It is also estimated that the males mature at a length between 12-14.5 inches and the females mature at a length between 15-17 inches.
Cookie cutter sharks are considered parasites, as their diet consists of mainly flesh and blubber, which is also how it got this common name. When this shark feeds, it attaches its teeth to its prey and spins 360 degrees, leaving very unique bite marks, looking like a cookie cutter just took a chunk of skin out of various sharks, large fish, whales, dolphins, squid, shellfish, seals and even some humans. Cookie cutter sharks get their calcium and phosphates unlike any other sea mammal. Once their teeth are worn and needing to be replaced, the cookie cutter shark will swallow their teeth rather than letting them fall out on to the ocean floor like most others. Their teeth are surprisingly their best source of calcium.