![]() ![]() Like other small sharks, this shark is oviparous, and the female coats her eggs in a horny casing before attaching them to rocks and seaweed. Fertilization is accomplished by his insertion of one of his claspers into the female's cloaca. The male has instead two 'claspers' (pterygopodes), located on his underside in the rear. Reproduction of the cookie-cutter shark is accomplished through internal fertilization. Females are larger than males, reaching perhaps 20 inches at full size. ![]() Coloration is medium grey to grey-brown, with a dark collar marking its throat. It has suctorial lips, small upper teeth, and large, triangular cusped lower teeth in 25 to 32 rows. The cookie-cutter shark is a typical member of the dogfish order it has no anal fin, a thin, cigar shaped body, and short snout. They tend to be found closer to islands, but they have been caught in open sea, as well. It is a deep-water fish, and wide-ranging, often found near islands.Ĭookie-cutter sharks are wide-ranging creatures, found in tropical oceanic climates all across the world. It is thought to happen in the wild when there is a shortage of males, and to be triggered in captive females after long enforced separation from males, involving a reshuffling of the mother’s genes to create offspring similar but not identical to the mother.Pelagic: The cookie-cutter shark is found in seas as far north as Japan and south to Southern Australia. The process has been known to occur in more than 80 vertebrate species, including 15 sharks and rays. Ispera’s mother had lived in the tank for 10 years with one other female, according to AGI, so the birth appeared to be a rare case of parthenogenesis, where an egg develops into an embryo without needing to be fertilised by a male’s sperm. Named Ispera (hope), it was born at the public aquarium at Cala Gonone. ***** MEANWHILE in Sardinia a baby smoothhound shark has been born in a tankful of females in what appears to be the first “virgin birth” for the species. There’s not very many animals that do something quite like this.” ![]() “They feed on everything from the biggest, toughest apex predators - like white sharks, orcas, everything you can imagine - down to the smallest little critters. “These animals occupy a unique ecological role in the world’s oceans,” he went on. “It turns out that all these bites we see on marine mammals and larger sport and commercial fishes and things really make up a relatively smaller amount of their diet,” said Carlisle. It also seemed that only bigger cookiecutters migrated vertically. It had previously been assumed that the sharks exhibited “vertical migration”, coming shallow only by night to feed on chunks of large prey, but now it seems that these forays merely provide a supplement to their regular diet of crustaceans, squid and small fish. Although the sharks’ stomachs were found mostly to be empty, they were able to apply a range of new biochemical tracing techniques, including environmental DNA analysis, to learn more about their feeding habits and habitats. The researchers used 14 cookiecutter sharks collected by the Monterey Bay Aquarium from the Pacific around Hawaii. These “crater wounds” are typically 5cm across and 7m deep.Ĭookiecutters, also known as cigar sharks, are common but live in deep water throughout the world’s tropical and subtropical seas, so little was known about them until a new study was carried out by a team led by associate professor Aaron Carlisle of the University of Delaware. Scientists have come across dolphins, swordfish, turtles, whales, white sharks and even human remains with distinctively shaped plugs of tissue taken from their bodies, and have also noted similar bites taken from underwater electrical cables. The species ( Isistius brasiliensis) is small, rarely growing longer than 56cm, and got its name because it was known to take bites out of other animals. ![]()
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