Tiger shark
| Tiger shark Temporal range: Early Eocene to Present
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| Genus: | Galeocerdo |
| Species: | G. cuvier
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| Galeocerdo cuvier | |
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Squalus cuvier Peron and Lessueur, 1822 | |
Template:Sharksportal The tiger shark, Galeocerdo cuvier is a species of requiem shark and the only member of the genus Galeocerdo. Mature sharks average 3.25 to 4.25 metres (10.7 to 13.9 ft) long[3][4] and weigh 385 to 635 kilograms (849 to 1,400 lb).[3] It can attain a length of over 5 metres (16 ft)[1] and a weight of 1,110 kilograms (2,450 lb) at maximum. It is found in many tropical and temperate oceans, and is especially common around central Pacific islands. This shark is a solitary, mostly night-time hunter. Its name derives from the dark stripes down its body, which fade as the shark matures.
The tiger shark is a predator, known for eating a wide range of animals. Its usual diet consists of fish, seals, birds, smaller sharks, squid, turtles, and dolphins. Tigers have been found with man-made waste such as license plates or pieces of old tires in their digestive tracts, thus the moniker, "the wastebasket of the sea".
This shark may be easily identified by its dark stripes which resemble a tiger's pattern. Its dorsal fins are distinctively close to its tail. They may encounter humans because they often visit shallow reefs, harbours and canals.
Second only to the great white shark in number of recorded attacks on humans,[5][6] the tiger is considered to be one of the sharks most dangerous to humans, along with the great white, bull shark and the oceanic whitetip shark.[7]
Taxonomy
The shark was first described by Peron and Lessueur in 1822 and was given the name Squalus cuvier.[8] Müller and Henle, in 1837 renamed it Galeocerdo tigrinus.[3] The genus, Galeocerdo, is derived from the Greek, galeos which means shark and the Latin cerdus which means the hard hairs of pigs.[3] It is often colloquially called the man-eater shark.[3]
The tiger shark is a member of the order Carcharhiniformes;[8] members of this order are characterized by the presence of a nictitating membrane over the eyes, two dorsal fins, an anal fin, and five gill slits. It is the largest member of the Carcharhinidae family, commonly referred to as requiem sharks. This family includes some other well-known sharks such as the blue shark, lemon shark and bull shark.
Range and habitat
The tiger shark is often found close to the coast, in mainly tropical and sub-tropical waters worldwide,[5] though they can reside in temperate waters. Along with the Pacific sleeper shark, Greenland shark and sixgill shark, tiger sharks are among the largest predatory sharks after the great white.[3] The shark's behavior is primarily nomadic, but is guided by warmer currents, and it stays closer to the equator throughout the colder months. The shark tends to stay in deep waters that line reefs but does move into channels to pursue prey in shallower waters. In the western Pacific Ocean, the shark has been found as far north as Japan and as far south as New Zealand.[9]
The shark has been recorded down to a depth just shy of 900 metres (3,000 ft)[3] but is also known to move into shallow water - water that is normally too shallow for a species of its size.
==Anatomy and appearance== this i fuckin shit
Its skin can typically range from blue to light green with a white or light yellow underbelly. Dark spots and stripes are most visible in young sharks and fade as the shark matures. Tiger sharks typically weigh 385 to 635 kilograms (849 to 1,400 lb)[3] and are usually 3.25 to 4.25 metres (10.7 to 13.9 ft) at maturity.[3] It has been estimated that the tiger shark can swim at a maximum speed of around 32 kilometres per hour (20 mph), with short bursts of higher speeds.[citation needed]
The tiger shark's head is somewhat wedge-shaped, which makes it easy to turn quickly to one side. Tigers have small pits on the side of their upper bodies which hold electrical sensors called the ampullae of lorenzini, enabling them to detect small muscle movements of other creatures, allowing them to hunt in darkness. The tiger shark has a reflective layer behind the retina called tapetum lucidum which allows light-sensing cells a second chance to capture photons of visible light, enhancing vision in low light conditions. A tiger shark generally has long fins to provide lift as the shark maneuvers through water. Its long upper tail provides bursts of speed. Tigers normally swims using small movements of its body. Its high back and dorsal fin act as a pivot, allowing it to spin quickly on its axis.
Its teeth are specialized to slice through flesh, bone, and other tough substances such as turtle shells, and unusually among sharks, its upper and lower teeth have dissimilar shapes. Like most sharks, however, its teeth are continually replaced by rows of new teeth.
Diet
The tiger shark, which generally hunts at night, has a reputation for eating anything it finds.[3][10] Its most common foods include: common fish, squid, seabirds, sea mammals, other sharks, and turtles.[3] The shark has a number of features which make it a good hunter, such as excellent eyesight and its acute sense of smell which enable it to react to faint traces of blood and follow them to the source. The tiger shark's ability to pick up on low-frequency pressure waves produced by moving animals, for example the thrashing of an injured animal, enables the shark to find a variety of prey.[citation needed]
The ability to pick up low-frequency pressure waves enables the shark to advance towards an animal with confidence, even in murky water.[11] The shark circles its prey and studies it by prodding it with its snout.[11] When attacking, the shark often eats its prey whole.[11] Because of its aggressive feeding, it often mistakenly eats inedible objects, such as automobile number plates, petroleum cans, tires, and baseballs. For this reason, the tiger shark is often regarded as the ocean's garbage can.[12]
Reproduction
Males reach sexual maturity at 2.3 to 2.9 metres (7 ft 7 in to 9 ft 6 in) and females at 2.5 to 3.5 metres (8 ft 2 in to 11 ft 6 in).[4] Females mate once every 3 years.[12] They breed by internal fertilization: the male inserts one of his claspers into the female's genital opening (cloaca), acting as a guide for the sperm. The male uses its teeth to hold the female still during the procedure, often causing the female considerable discomfort. Mating in the northern hemisphere generally takes place between March and May, with birth between April and June the following year. In the southern hemisphere, mating takes place in November, December, or early January. The tiger is the only species in its family that is ovoviviparous; its eggs hatch internally and the young are born live when fully developed.[3]
The young develop inside the mother's body for up to 16 months. Litters range from 10 to 80 pups.[3] A newborn is generally 51 centimetres (20 in) to 76 centimetres (30 in) long[3]. It is unknown how long tiger sharks live, but they can live longer than 12 years.[12]
Dangers and conservation
Although shark attacks are a relatively rare phenomenon, the tiger is responsible for a large percentage of fatal attacks, and is regarded as one of the most dangerous species.[6][13] Tiger sharks are often found in river estuaries and harbours, as well as shallow water close to shore, where they are bound to encounter humans. Tiger sharks also dwell in river mouths and other runoff-rich water.[3][4]
Tiger sharks are considered to be sacred nā ʻaumākua (ancestor spirits) by native Hawaiians, who think their eyeballs have special seeing powers. However between 1959 and 1976, 4,668 tiger sharks were taken in an effort to protect the tourism industry. Despite these efforts attacks did not decrease. It is illegal to feed sharks in Hawaiʻi and interaction with them, such as cage diving, is discouraged.[14] South African shark scientist Mark Addison demonstrated that they could be tamed somewhat in a 2007 Discovery Channel special.[15]
While the tiger shark is not commercially fished, it is caught for its fins, flesh, liver, which is a valuable source of vitamin A used in the production of vitamin oils, and for its distinct skin, as well as by big game fishers.[3]
See also
- List of sharks
- List of prehistoric cartilaginous fish
- List of fatal, unprovoked shark attacks in the United States by decade
References
- ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Chondrichthyes entry)". Bulletins of American Paleontology. 364: 560. Retrieved 2008-01-09.
- ^ Template:IUCN2006 Database entry includes justification for why this species is near threatened
- ^ a b c d e f g h i j k l m n o p "Tiger Shark Biological Profile". Florida Museum of Natural History Icthyology Department. Retrieved 2005-01-22.
- ^ a b c "Galeocerdo cuvier Tiger Shark". Marine Bio. Retrieved 2006-10-14.
- ^ a b Knickle, Craig. "Florida Museum of Natural History Ichthyology Department". www.flmnh.ufl.edu. Retrieved 2009-07-02.
- ^ a b "ISAF Statistics on Attacking Species of Shark". Florida Museum of Natural History University of Florida. Retrieved 2008-05-04.
- ^ Daley, Audrey (1994). Shark. Hodder & Stroughton. ISBN 0-340-61654-7.
{{cite book}}: Cite has empty unknown parameter:|unused_data=(help); Unknown parameter|ISBN status=ignored (help) - ^ a b "ITIS report, Galeocerdo cuvier". Taxonomic Information System. Retrieved 2006-09-22.
- ^ "Galeocerdo cuvier". Fishbase. Retrieved 2006-09-28.
- ^ http://community.oceana.org/creatures/tiger-shark
- ^ a b c "Tiger Shark". ladywildlife.com. Retrieved 2006-12-21.
- ^ a b c Ritter, Erich K. (15 Dec 1999). "Fact Sheet: Tiger Sharks". Shark Info. Retrieved 2009-05-15.
- ^ Ritter, Erich K. "Which shark species are really dangerous?". Shark Info. Retrieved 2009-05-15.
- ^ "Federal Fishery Managers Vote To Prohibit Shark Feeding" (PDF). Western Pacific Regional Fishery Management Council. Retrieved 2007-06-15.
- ^ "Shark Week: 'Deadly Stripes: Tiger Sharks'". LA Times. 30 July 2007. Retrieved 2007-09-28.
- General references
- Froese, Rainer; Pauly, Daniel (eds.). "Galeocerdo cuvier". FishBase. March 2005 version.
- "Galeocerdo cuvier". Integrated Taxonomic Information System. 7 April.
{{cite web}}: Check date values in:|date=and|year=/|date=mismatch (help) - Tiger shark, Galeocerdo cuvier at marinebio.org
- "Tiger shark, Galeocerdo cuvier" at the Encyclopedia of Life
- General information Enchanted Learning. Retrieved January 22, 2005.
- Different diet information Shark Info. Retrieved January 22, 2005.
- Tiger sharks in Hawaii Research program. Retrieved January 22, 2005.
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