The Cookiecutter shark technically feeds on any medium to large oceanic animal that shares habitat with this species. Unlike other sharks, the retina of the Cookiecutter shark has ganglion cells a type of neuron located near the inner surface of the retina of the eye concentrated in a concentric area rather than a horizontal streak across the visual field this may help to focus on prey in front of the shark. The Cookiecutter shark regularly replaces its teeth like other sharks but sheds its lower teeth in entire rows at the time. The maximum recorded length for this species is 42 cm for males and 56 cm for females. Complex, light-producing organs called photophores densely cover the entire underside, except for the collar, and produce a vivid green glow. The fins have translucent margins, except for the caudal fin. There is no anal fin, and the caudal fin is broad, with the lower lobe almost as large as the upper, which has a prominent ventral notch. Two spineless dorsal fins are placed far back on the body, the second being larger than the first one. The pectoral fins are short and trapezoidal in shape. The name “cookiecutter” refers to its feeding habit of gouging round plugs as if cut out with a cookie cutter. The upper jaw has 30 – 37 seven tooth rows and in the lower jaw, there are 25-31 tooth rows. The large, oval, green eyes are placed forward on the head, enough to allow the shark to have binocular vision. The cookiecutter shark has an elongated, cigar-shaped body with a short, bulbously rounded snout. However, researchers found one cookiecutter shark in the stomach of a large bluefin tuna, suggesting the tactic isn't foolproof.The Cookiecutter shark, also called the cigar shark, is a species of small dogfish shark in the family Dalatiidae. One specimen was caught at a depth of 9,840 feet (3,000 meters), Papastamatiou said.īut how wise is it to attack large predator 10 times your size? There's almost no evidence of how often the cookiecutter's bold strategy fails, Papastamatiou said. They often dive during the day and come near the surface at night. Cookiecutter sharks range throughout the world in tropical and subtropical waters. The cookiecutter shark (Isistius brasiliensis) can grow up to 20 inches (50 centimeters) long, while great whites can reach lengths of nearly 20 feet (6 meters), according to the International Union for Conservation of Nature. Scientists don't think bites from the cookiecutters can seriously harm these large predators. "This really shows there's no marine predator that can't be attacked by this little shark, which is impressive," he said. The sharks have been known to prey on a wide variety of marine animals, including swordfish, whales, orcas and even a human swimmer - and now, great white sharks. "Animals at the top of the food chain can still get attacked by things a lot smaller than them," Papastamatiou told OurAmazingPlanet. It's the first photographic evidence of such a bite, said study author Yannis Papastamatiou, a marine biologist at the Florida Museum of Natural History. Great whites are about 10 times the size of a cookiecutter shark.ĭivers in a shark tank off of Guadalupe Island, which is about 150 miles (240 kilometers) west of Mexico's Baja California peninsula, took a photograph of a great white sporting a fresh bite from a cookiecutter, as documented in a study published recently in the journal Pacific Science. But unlike typical meat eaters, these sharks don't kill their prey - they just take a bite and move on.Īnd for the first time, scientists have found evidence that these small sharks even go after one of the world's most fearsome predators, the great white shark. Like most sharks (or any marine animal, for that matter), cookiecutters roam the ocean looking for food. Cookiecutter sharks aren't very neighborly.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |