   #copyright

Cookiecutter shark

2007 Schools Wikipedia Selection. Related subjects: Insects, Reptiles and
Fish

               iCookiecutter shark
   Drawing by Dr Tony Ayling
   Drawing by Dr Tony Ayling

                             Conservation status

   Least Concern (LC)
            Scientific classification

   Kingdom:    Animalia
   Subkingdom: Deuterostomia
   Phylum:     Chordata
   Class:      Chondrichthyes
   Subclass:   Elasmobranchii
   Order:      Squaliformes
   Family:     Dalatiidae
   Genus:      Isistius
   Species:    I. brasiliensis

                                Binomial name

   Isistius brasiliensis
   ( Quoy & Gaimard, 1824)

   The cookiecutter shark, Isistius brasiliensis, also known as the cigar
   shark or luminous shark, is a small rarely-seen dogfish shark.

Naming

   It gets its name from its feeding style which often creates perfect
   "cookie-cutter" shaped plugs in the skin of large marine mammals and
   other large sharks.

Habitat and distribution

   Worldwide in deep water. The cookiecutter shark has been found at
   depths of about 1,000 m (3,300 ft) below the surface of the ocean.

Anatomy and appearance

   The cookiecutter sharks often glow green and grow up to 50 cm (20 in)
   long. The underside of the shark is bioluminescent, glowing a pale
   blue-green that matches the background light from the ocean's surface
   that serves as camouflage to creatures beneath it. However, a small
   non-luminescent patch appears black, deceiving the shark's prey,
   smaller predatory fish (like tuna), into thinking the shark is an even
   smaller fish. When the predatory fish tries to strike at the shark, the
   shark strikes back, scoring itself another meal . This is the only
   known instance whereby a bioluminescent lure is created by the absence
   of luminescence (contrast with anglerfish).

Diet

   It derived its name from its habit of removing small circular chunks of
   flesh from whales and large fish. It is hypothesized that the shark
   seizes its much larger prey with its jaws, then rotates its body to
   achieve a highly symmetrical cut. They are considered a parasite.

Reproduction

   Cookiecutter sharks reproduce through aplacental viviparity in the same
   way as great white sharks. Little else is known about their
   reproduction.

Interaction with humans

   There has been little interaction between humans and the cookiecutter
   shark. However, there was an incident in which a cookiecutter shark
   took a bite out of a the rubber sonar dome of a US Navy submarine,
   causing damage to the housing, and forcing the submarine out of service
   until the rubber could be replaced.

   Retrieved from " http://en.wikipedia.org/wiki/Cookiecutter_shark"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
