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Great white shark
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Great white shark
Temporal range: 16–0Ma[1]
PreЄ
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O
S
D
C
P
T
J
K
Pg
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Miocene to Recent
White shark.jpg
Great white shark size comparison.svg
Conservation status


Vulnerable (IUCN 3.1)[2]

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Lamniformes
Family: Lamnidae
Genus: Carcharodon
A. Smith, 1838
Species: C. carcharias
Binomial name
Carcharodon carcharias
(Linnaeus, 1758)
Cypron-Range Carcharodon carcharias.svg
Global range highlighted in blue
The great white shark (Carcharodon carcharias), also known as the great white, white pointer, white shark, or white death, is a species of large lamniform shark which can be found in the coastal surface waters of all the major oceans. The great white shark is mainly known for its size, with mature individuals growing up to 6.4 m (21 ft) in length (although reports have been published of great white sharks measuring over 8 m (26 ft),[3] and 3,324 kg (7,328 lb) in weight).[4][5][6][7] This shark reaches its maturity around 15 years of age and was previously believed to have a life span of over 30 years. The true lifespan of great white sharks is far longer; now estimated to be as long as 70 years or more, making it one of the longest lived cartilaginous fish currently known.[8] Great white sharks can accelerate to speeds that exceed 56 km/h (35 mph).[9]
The great white shark has no natural predators other than the Orca.[10] The great white shark is arguably the world's largest known extant macropredatory fish, and is one of the primary predators of marine mammals. It is also known to prey upon a variety of other marine animals, including fish and seabirds. It is the only known surviving species of its genus Carcharodon, and is ranked first in having the most attacks on humans.[11][12] The IUCN list the great white shark as a vulnerable species,[2] while it is included in Appendix II of CITES.[13]
The bestselling novel Jaws by Peter Benchley and the subsequent blockbuster film by Steven Spielberg depicted the great white shark as a "ferocious man eater". In reality, humans are not the preferred prey of the great white shark,[14] however of all shark species, the great white shark is responsible for by far the largest number of fatal unprovoked attacks on humans.[15]


Contents  [hide]
1 Taxonomy 1.1 Ancestry and fossil record
2 Distribution and habitat
3 Anatomy and appearance 3.1 Size
3.2 Adaptations
3.3 Bite force
4 Ecology and behavior 4.1 Diet
4.2 Reproduction
4.3 Breaching behaviour
4.4 Natural threats
5 Relationship with humans 5.1 Shark attacks
5.2 Attacks on boats
5.3 Great white sharks in captivity
5.4 Shark tourism
6 Conservation status 6.1 In Australia
6.2 In New Zealand
6.3 In North America
7 See also
8 References
9 External links 9.1 News and articles
9.2 Photographic depictions and tagging activities
9.3 Videos


Taxonomy
In 1758, Carolus Linnaeus gave the great white shark its first scientific name, Squalus carcharias. Later, Sir Andrew Smith gave it Carcharodon as its generic name in 1833, and also in 1873. The generic name was identified with Linnaeus' specific name and the current scientific name Carcharodon carcharias, was finalized. Carcharodon comes from the Greek words karcharos, which means sharp or jagged, and odous, which means tooth.[16]



 A 4-cm-tall fossil C. carcharias tooth from Miocene sediments in the Atacama Desert of Chile
Ancestry and fossil record
The great white shark came into existence during the mid-Miocene epoch. The earliest known fossils of the great white shark are about 16 million years old.[1] However, the phylogeny of the great white is still in dispute. The original hypothesis for the great white's origins is that it shares a common ancestor with a prehistoric shark, such as the C. megalodon. Similarities among the physical remains and the extreme size of both the great white and C. megalodon led many scientists to believe these sharks were closely related, and the name Carcharodon megalodon was applied to the latter. However, a new hypothesis proposes that the C. megalodon and the great white are distant relatives (albeit sharing the family Lamnidae). The great white is also more closely related to an ancient mako shark, Isurus hastalis, than to the C. megalodon, a theory that seems to be supported with the discovery of a complete set of jaws with 222 teeth and 45 vertebrae of the extinct transitional species Carcharodon hubbelli in 1988 and published on 14 November 2012.[17] In addition, the new hypothesis assigns C. megalodon to the genus Carcharocles, which also comprises the other megatoothed sharks; Otodus obliquus is the ancient representative of the extinct Carcharocles lineage.[18]
Distribution and habitat



 Great white shark off Guadalupe Island, Mexico
Great white sharks live in almost all coastal and offshore waters which have water temperature between 12 and 24 °C (54 and 75 °F), with greater concentrations in the United States (Atlantic Northeast and California), South Africa, Japan, Oceania, Chile, and the Mediterranean.[19] One of the densest known populations is found around Dyer Island, South Africa, where almost all of the shark research is done.
The great white is an epipelagic fish, observed mostly in the presence of rich game, such as fur seals, sea lions, cetaceans, other sharks, and large bony fish species. In the open ocean, it has been recorded at depths as great as 1,200 m (3,900 ft).[20] These findings challenge the traditional notion about the great white as being a coastal species.[20]
According to a recent study, California great whites have migrated to an area between Baja California and Hawaii known as the White Shark Café to spend at least 100 days before migrating back to Baja. On the journey out, they swim slowly and dive down to around 900 m (3,000 ft). After they arrive, they change behavior and do short dives to about 300 m (1,000 ft) for up to ten minutes. Another white shark that was tagged off of the South African coast swam to the southern coast of Australia and back within the year. A similar study tracked a different great white shark from South Africa swimming to Australia's northwestern coast and back, a journey of 20,000 km (12,000 mi; 11,000 nmi) in under nine months.[21] These observations argue against traditional theories that white sharks are coastal territorial predators, and open up the possibility of interaction between shark populations that were previously thought to have been discrete. The reasons for their migration and what they do at their destination is still unknown. Possibilities include seasonal feeding or mating.[22]
Anatomy and appearance
The great white shark has a robust, large, conical snout. The upper and lower lobes on the tail fin are approximately the same size which is similar to some mackerel sharks.
A great white displays countershading, by having a white underside and a grey dorsal area (sometimes in a brown or blue shade) that gives an overall mottled appearance. The coloration makes it difficult for prey to spot the shark because it breaks up the shark's outline when seen from the side. From above, the darker shade blends with the sea and from below it exposes a minimal silhouette against the sunlight.
Great white sharks, like many other sharks, have rows of serrated teeth behind the main ones, ready to replace any that break off. When the shark bites, it shakes its head side-to-side, helping the teeth saw off large chunks of flesh.[23]
Size



 Great white shark caught off Cuba in 1945 which is allegedly 6.4 m (21 ft) long and weighed an estimated 3,175 kg (7,000 lb).[24]
Male great whites reach maturity at 3.5–4.0 m (11.5–13.1 ft) long and females at 4.5–5.0 m (14.8–16.4 ft) long. Adults on average are 4–5.2 m (13–17 ft) long and have a mass of 680–1,100 kg (1,500–2,430 lb). Females are generally larger than males. The great white shark can reach 6.4 m (21 ft) in length and 3,324 kg (7,328 lb) in weight.[3][4][5][6][7] The maximum size is subject to debate because some reports are rough estimations or speculations performed under questionable circumstances.[25] Among living cartilaginous fish, only the basking and whale sharks and the manta ray average larger and heavier. These three species are generally docile in disposition and given to passively filter-feeding on very small organisms.[26]
A number of very large great white shark specimens have been recorded.[27] For decades, many ichthyological works, as well as the Guinness Book of World Records, listed two great white sharks as the largest individuals: In the 1870s, a 10.9 m (36 ft) great white captured in southern Australian waters, near Port Fairy, and an 11.3 m (37 ft) shark trapped in a herring weir in New Brunswick, Canada, in the 1930s. Some researchers question these measurements' reliability, noting they were much larger than any other accurately reported sighting. This New Brunswick shark may have been a misidentified basking shark, as the two have similar body shapes. The question of the Port Fairy shark was settled in the 1970s when J. E. Randall examined the shark's jaws and "found that the Port Fairy shark was of the order of 5 m (17 ft) in length and suggested that a mistake had been made in the original record, in 1870, of the shark's length".[28]
According to J. E. Randall, the largest white shark reliably measured was a 6.0 m (19.7 ft) individual reported from Ledge Point, Western Australia in 1987.[28] Another great white specimen of similar size has been verified by the Canadian Shark Research Center: A female caught by David McKendrick of Alberton, Prince Edward Island, in August 1988 in the Gulf of St. Lawrence off Prince Edward Island. This female great white was 6.1 m (20 ft) long.[7] However, there is a report considered reliable by some experts of a larger great white shark specimen from Cuba in 1945. This specimen was 6.4 m (21 ft) long and had a body mass of about 3,324 kg (7,328 lb).[4][5]

Photo of large shark on shore surrounded by people

 Great white shark caught off Hualien County, Taiwan, on 14 May 1997: It was reportedly almost 7 m (23 ft) in length with a mass of 2,500 kg (5,500 lb).[27]
Several great white sharks caught in modern times have been estimated to be more than 7 m (23 ft) long,[29] but these claims have received some criticism.[25][29] However, J. E. Randall believed that great white shark may have exceeded 6.1 m (20 ft) in length.[28] A great white shark was captured near Kangaroo Island in Australia on 1 April 1987. This shark was estimated to be more than 7 m (23 ft) long by Peter Resiley,[28][30] and has been designated as KANGA.[29] Another great white shark was caught in Malta by Alfredo Cutajar on 16 April 1987. This shark was also estimated to be around 7.13 m (23.4 ft) long by John Abela and has been designated as MALTA.[29] However, Cappo drew criticism because he used shark size estimation methods proposed by J. E. Randall to suggest that the KANGA specimen was 5.8–6.4 m (19–21 ft) long.[29] In a similar fashion, I. K. Fergusson also used shark size estimation methods proposed by J. E. Randall to suggest that the MALTA specimen was 5.3–5.7 m (17–19 ft) long.[29] However, photographic evidence suggested that these specimens were larger than the size estimations yielded through Randall's methods.[29] Thus, a team of scientists—H. F. Mollet, G. M. Cailliet, A. P. Klimley, D. A. Ebert, A. D. Testi, and L. J. V. Compagno—reviewed the cases of the KANGA and MALTA specimens in 1996 to resolve the dispute by conducting a comprehensive morphometric analysis of the remains of these sharks and re-examination of photographic evidence in an attempt to validate the original size estimations and their findings were consistent with them. The findings indicated that estimations by P. Resiley and J. Abela are reasonable and could not be ruled out.[29]



 Great white shark's skeleton
One contender in maximum size is the tiger shark, Galeocerdo cuvier. While tiger sharks which are typically both a few feet smaller and have a leaner, less heavy body structure than white sharks, have been confirmed to reach at least 5.5 metres (18 ft) in the length, an unverified specimen was reported to have measured 7.4 metres (24 ft) in length and weighed 3,110 kilograms (6,860 lb).[26][31] Some other macropredatory sharks such as the Greenland shark, Somniosus microcephalus, and the Pacific sleeper shark, Somniosus pacificus, are also reported to rival these sharks in length (but probably weigh a bit less since they are more slender in build than a great white) in exceptional cases.[32][33] The question of maximum weight is complicated by the unresolved question of whether or not to include the shark's stomach contents when weighing the shark. With a single bite a great white can take in up to 14 kg (31 lb) of flesh, and can also consume several hundred kilograms of food.
The largest great white recognized by the International Game Fish Association (IGFA) is one caught by Alf Dean in the south Australian waters in 1959, weighing 1,208 kg (2,663 lb).[25] Several larger great whites caught by anglers have since been verified, but were later disallowed from formal recognition by IGFA monitors for rules violations.
Adaptations

Photo of shark swimming at water surface

 A great white shark swimming
Great white sharks, like all other sharks, have an extra sense given by the Ampullae of Lorenzini which enables them to detect the electromagnetic field emitted by the movement of living animals. Every time a living creature moves, it generates an electrical field and great whites are so sensitive they can detect half a billionth of a volt. Even heart beats emit a very faint electrical pulse. If it is close enough, the shark can detect even that faint electrical pulse. Most fish have a less-developed but similar sense using their body's lateral line.[34]



 Great white shark biting into the fish head teaser bait next to a cage in False Bay, South Africa.
To more successfully hunt fast and agile prey such as sea lions, the great white has adapted to maintain a body temperature warmer than the surrounding water. One of these adaptations is a "rete mirabile" (Latin for "wonderful net"). This close web-like structure of veins and arteries, located along each lateral side of the shark, conserves heat by warming the cooler arterial blood with the venous blood that has been warmed by the working muscles. This keeps certain parts of the body (particularly the stomach) at temperatures up to 14 °C (25 °F)[35] above that of the surrounding water, while the heart and gills remain at sea temperature. When conserving energy the core body temperature can drop to match the surroundings. A great white shark's success in raising its core temperature is an example of gigantothermy. Therefore, the great white shark can be considered an endothermic poikilotherm because its body temperature is not constant but is internally regulated.[23] Great whites also rely on the fat and oils stored within their livers for long distance migrations across nutrient-poor areas of the oceans.[36] Studies by Stanford University and the Monterey Bay Aquarium published on 17 July 2013 revealed that In addition to controlling the sharks' buoyancy, the liver of great whites is essential in migration patterns. Sharks that sink faster during drift dives were revealed to use up their internal stores of energy quicker than those which sink in a dive at more leisurely rates.[37]
Bite force
A 2007 study from the University of New South Wales in Sydney, Australia, used CT scans of a shark's skull and computer models to measure the shark's maximum bite force. The study reveals the forces and behaviors its skull is adapted to handle and resolves competing theories about its feeding behavior.[38] In 2008, a team of scientists led by Stephen Wroe conducted an experiment to determine the great white shark's jaw power and findings indicated that a specimen more than 6.1 m (20 ft) long could exert a bite force of over 18,000 newtons (4,000 lbf).[5]
Ecology and behavior

Photo of inverted shark at surface

 A great white shark turns onto its back while hunting tuna bait
This shark's behavior and social structure is not well understood. In South Africa, white sharks have a dominance hierarchy depending on the size, sex and squatter's rights: Females dominate males, larger sharks dominate smaller sharks, and residents dominate newcomers. When hunting, great whites tend to separate and resolve conflicts with rituals and displays. White sharks rarely resort to combat although some individuals have been found with bite marks that match those of other white sharks. This suggests that when another shark approaches too closely to another great white, they react with a warning bite. Another possibility is that white sharks bite to show their dominance.
The great white shark is one of only a few sharks known to regularly lift its head above the sea surface to gaze at other objects such as prey. This is known as spy-hopping. This behavior has also been seen in at least one group of blacktip reef sharks, but this might be learned from interaction with humans (it is theorized that the shark may also be able to smell better this way because smell travels through air faster than through water). The white sharks are generally very curious animals, display intelligence and may also turn to socializing if the situation demands it. At Seal Island, white sharks have been observed arriving and departing in stable "clans" of two to six individuals on a yearly basis. Whether clan members are related is unknown but they get along peacefully enough. In fact, the social structure of a clan is probably most aptly compared to that of a wolf pack; in that each member has a clearly established rank and each clan has an alpha leader. When members of different clans meet, they establish social rank nonviolently through any of a fascinating variety of interactions.[39]
Diet



 A great white shark scavenging on a whale carcass
Great white sharks are carnivorous and prey upon fish (e.g. tuna, rays,[39] other sharks[39]), cetaceans (i.e., dolphins, porpoises, whales), pinnipeds (e.g. seals, fur seals,[39] and sea lions), sea turtles,[39] sea otters, and seabirds.[40] Great whites have also been known to eat objects that they are unable to digest. Upon approaching a length of nearly 4 metres (13 ft), great white sharks begin to target predominately marine mammals for food.[41] These sharks prefer prey with a high content of energy-rich fat. Shark expert Peter Klimley used a rod-and-reel rig and trolled carcasses of a seal, a pig, and a sheep from his boat in the South Farallons. The sharks attacked all three baits but rejected the sheep carcass.[42]
The great white shark's reputation as a ferocious predator is well-earned, yet they are not (as was once believed) indiscriminate "eating machines". They are ambush hunters, taking prey by surprise from below. Near Seal Island, in South Africa's False Bay, shark attacks most often occur in the morning, within 2 hours after sunrise, when visibility is poor. Their success rate is 55% in the first 2 hours, falling to 40% in late morning after which hunting stops.[39]
Hunting techniques vary by species of the prey. Off Seal Island, the sharks ambush brown fur seals from below at high speeds, hitting the seal mid-body. They go so fast that they can completely leave the water. The peak burst speed of these sharks is largely accepted in the scientific community to be above 40 kilometres per hour (25 mph). However further precision is still speculative.[43] They have also been observed chasing prey after a missed attack. Prey is usually attacked at the surface.[44]
Off California, sharks immobilize northern elephant seals with a large bite to the hindquarters (which is the main source of the seal's mobility) and wait for the seal to bleed to death. This technique is especially used on adult male elephant seals which can be as large or larger than the hunter and are potentially dangerous adversaries. Prey is normally attacked sub-surface. Harbour seals are taken from the surface and dragged down until they stop struggling. They are then eaten near the bottom. California sea lions are ambushed from below and struck mid-body before being dragged and eaten.[45]
Off The East Coast of North America, where white sharks are still poorly understood, individuals have been filmed and documented hunting grey seals. When hunting, atlantic great whites will hunt very close to shore, unlike their counterparts elsewhere which prefer deeper water for ambush and breach attacks. The sharks also utilize sandbars to set up ambushes, and will then chase the seals in a flat-out pursuit. This behavior was revealed to the public media during two episodes of Shark Week, the first being "Jaws Comes Home" and the second being "Return of Jaws".
White sharks also attack dolphins and porpoises from above, behind or below to avoid being detected by their echolocation. Targeted species include dusky dolphins,[29] Risso's dolphins,[29] bottlenose dolphins,[29][46] Humpback dolphins,[46] harbour porpoises,[29] and Dall's porpoises.[29] Close encounters between dolphins and predatory sharks often result in evasive responses by the dolphins.[46] However, in rare cases, a group of dolphins may chase a single predatory shark away in an act of defense.[46] White shark predation on other species of small cetacean has also been observed. In August 1989, a 1.8 metres (5.9 ft) juvenile male pygmy sperm whale, Kogia breviceps, stranded in central California with a bite mark on its caudal peduncle from a great white shark.[47] In addition, white sharks also attack and prey upon beaked whales.[29][46]



 A beachcomber looking at bite marks on a beached whale carcass from a great white shark
Even though the great whites are known to generally avoid conflicts with each other, the phenomenon of cannibalism is not alien to this species. Large individuals may aggressively interact intraspecifically with small individuals. A 3 m (9.8 ft) long great white shark was nearly bitten into two by a reportedly 6 m (20 ft) long great white shark in Stradbroke Island, near Brisbane in Australia.[48]
White sharks also scavenge on whale carcasses. In one such documented incident, white sharks were observed scavenging on a whale carcass alongside tiger sharks.[49]
Reproduction
Almost nothing is known about the reproduction of great whites. Some evidence points to the near-soporific effect of a large feast (such as a whale carcass) possibly inducing mating.[50] Great white sharks also reach sexual maturity at around 15 years of age.[51] Maximum life span was originally believed to be more than 30 years, but in a study by the Woods Hole Oceanographic Institution, the true lifespan of the great white shark was revealed to be up to 70 years or more, with examinations of growth ring count in vertebrae including ages of 73 years old in the oldest male and 40 years old in the oldest female in the study, making the species far more vulnerable to pressures such as overfishing and environmental change.[8] (see references).
Little is known about the great white shark's behavior in the way of mating habits. Birth has never been observed, but pregnant females have been examined. Great white sharks are ovoviviparous, which means eggs develop and hatch in the uterus and continue to develop until birth.[52] The great white has an 11-month gestation period. The shark pup's powerful jaws begin to develop in the first month. The unborn sharks participate in oophagy, in which they feed on ova produced by the mother. Delivery is in spring and summer.[53] The Northern Pacific population of great whites is suspected to breed off of the Sea of Cortez (as was revealed in the Shark Week episode "Spawn of Jaws"), as evidenced by local fisherman who have said to have caught them and evidenced by teeth found at dump sites for discarded parts from their catches. If the Sea of Cortez is such a breeding ground, it is imperative that the area's laws be better enforced to ensure the survival of the breeding population.
Breaching behaviour
A breach is the result of a high speed approach to the surface with the resulting momentum taking the shark partially or completely clear of the water. This is a hunting technique employed by great white sharks whilst hunting seals. This behavior often takes place on cape fur seals at Seal Island in False Bay, South Africa but due to the randomness of the location of a shark's breach, it was very hard to document. It was first photographed by Chris Fallows and Rob Lawrence who developed the technique of towing a slow moving seal decoy to trick the sharks to breach.[54] Here, in the region of 600 natural predatory events are recorded annually from April to September each year. The seals swim on the surface and the great white sharks launch their predatory attack from the deeper water below. They can reach speeds of up to 40 kilometres per hour (25 mph) and can at times launch themselves more than 10 feet (3.0 m) into the air. Data recorded shows that the sharks are successful in just under 50% of all these natural predatory events.[55] In 2011, a 3 metres (9.8 ft) long shark jumped onto a seven-person research vessel off Seal Island in Mossel Bay. The crew were undertaking a population study using sardines as bait, and the incident was judged to be an accident.[56]
Natural threats
Interspecific competition between the great white shark and the orca is probable in regions where dietary preferences of both species may overlap.[46] An incident was documented on 4 October 1997, in the Farallon Islands off California in the United States. An estimated 4.7–5.3-metre (15–17 ft) female orca immobilized an estimated 3–4-metre (9.8–13.1 ft) great white shark.[57] The orca held the shark upside down to induce tonic immobility and kept the shark still for fifteen minutes, causing it to suffocate and then proceeded to eat the dead shark's liver.[46][57][58] It is believed that the scent of the slain shark's carcass caused all the great whites in the region to flee, forfeiting an opportunity for a great seasonal feed.[59] Another similar attack apparently occurred there in 2000, but its outcome is not clear.[60] After both attacks, the local population of about 100 great whites vanished.[58][60] Following the 2000 incident, a great white with a satellite tag was found to have immediately submerged to a depth of 500 m (1,600 ft) and swam to Hawaii.[60]
Relationship with humans
Shark attacks
Main article: Shark attack
Of all shark species, the great white shark is responsible for by far the largest number of recorded shark attacks on humans, with 272 documented unprovoked attacks on humans in which the great white shark was identified as of 2012.[15]
More than any documented attack, Peter Benchley's best-selling novel Jaws and the subsequent 1975 film adaptation directed by Steven Spielberg provided the great white shark with the image of being a "man eater" in the public mind.[61] While great white sharks have killed humans in at least 74 documented unprovoked attacks in which the species was identified, they typically do not target them: for example, in the Mediterranean Sea there have been 31 confirmed attacks against humans in the last two centuries, most of which were non-fatal. Many of the incidents seemed to be "test-bites". Great white sharks also test-bite buoys, flotsam, and other unfamiliar objects, and they might grab a human or a surfboard to identify what it is.

Photo of open-mouthed shark at surface.

 The great white shark is one of only four kinds of sharks that have been involved in a significant number of fatal unprovoked attacks on humans.
Other incidents seem to be cases of mistaken identity, in which a shark ambushes a bather or surfer from below, believing the silhouette is from a seal. Many attacks occur in waters with low visibility or other situations which impair the shark's senses. The species appears to not like the taste of humans, or at least finds the taste unfamiliar. Further research shows that they can tell in one bite whether or not the object is worth attacking. Humans, for the most part, are too bony for their liking. They much prefer a fat, protein-rich seal.[62]
However, some researchers have hypothesized that the reason the proportion of fatalities is low is not because sharks do not like human flesh, but because humans are often able to escape after the first bite. In the 1980s John McCosker, the Chair of Aquatic Biology at California Academy, noted that divers who dove solo and were attacked by great whites were generally at least partially consumed, while divers who followed the buddy system were generally rescued by their buddy. McCosker and Timothy C. Tricas, an author and professor at the University of Hawaii, suggest that a standard pattern for great whites is to make an initial devastating attack and then wait for the prey to weaken before consuming the wounded animal. Humans' ability to move out of reach with the help of others, thus foiling the attack, is unusual for a great white's prey.[63]
Humans are not appropriate prey because the shark's digestion is too slow to cope with a human's high ratio of bone to muscle and fat. Accordingly, in most recorded attacks, great whites broke off contact after the first bite. Fatalities are usually caused by blood loss from the initial bite rather than from critical organ loss or from whole consumption. From 1990 until 2011 there have been a total of 139 unprovoked great white shark attacks, 29 fatal.[64]
Attacks on boats
Great white sharks infrequently attack and sometimes even sink boats. Only five of the 108 authenticated unprovoked shark attacks reported from the Pacific Coast during the 20th century involved kayakers.[65] In a few cases they have attacked boats up to 10 metres (33 ft) in length. They have bumped or knocked people overboard, usually attacking the boat from the stern. In one case in 1936, a large shark leapt completely into the South African fishing boat Lucky Jim, knocking a crewman into the sea. Tricas and McCosker's underwater observations suggest that sharks are attracted to boats due to the electrical fields they generate.[66]
Great white sharks in captivity

Photo of shark

 Great white shark in the Monterey Bay Aquarium in September 2006
Prior to August 1981, no great white shark in captivity lived longer than 11 days. In August 1981, a white shark survived for 16 days at SeaWorld San Diego before being released.[67] The idea of containing a live great white at SeaWorld Orlando was used in the 1983 film Jaws 3-D.
In 1984, shortly before its opening day, the Monterey Bay Aquarium in Monterey, California, housed its first great white shark which had died after 10 days. In July 2003, Monterey researchers captured a small female and kept it in a large netted pen near Malibu for five days. They had the rare success of getting the shark to feed in captivity before its release.[68] Not until September 2004 was the aquarium able to place a great white on long-term exhibit. A young female, which was caught off the coast of Ventura, was kept in the aquarium's massive 3,800,000-litre (1,000,000 US gal) Outer Bay exhibit for 198 days before she was released in March 2005. She was tracked for 30 days after release.[69] On the evening of 31 August 2006, the aquarium introduced a juvenile male caught outside Santa Monica Bay.[70] His first meal as a captive was a large salmon steak on 8 September 2006, and as of that date, he was estimated to be 1.72 metres (68 in) in length and to weigh approximately 47 kilograms (104 lb). He was released on 16 January 2007, after 137 days in captivity.
In addition, Monterey Bay Aquarium housed a third great white, a juvenile male, for 162 days between 27 August 2007, and 5 February 2008. On arrival, he was 1.4 metres (4 ft 7 in) long and weighed 30.6 kilograms (67 lb). He grew to 1.8 metres (5 ft 11 in) and 64 kilograms (141 lb) before release. A juvenile female came to the Outer Bay Exhibit on 27 August 2008. While she did swim well, the shark fed only one time during her stay and was tagged and released on 7 September 2008. Another juvenile female was captured near Malibu on 12 August 2009, introduced to the Outer Bay exhibit on 26 August 2009, and was successfully released into the wild on 4 November 2009.[71] The Monterey Bay Aquarium recently added a 1.4 metres (4.6 ft) long male into their redesigned "Open Sea" exhibit on 31 August 2011. The animal was harvested in the waters off of Malibu.
Probably the most famous captive was a 2.4 metres (7.9 ft) female named Sandy, which in August 1980 became the only great white to be housed at the California Academy of Sciences' Steinhart Aquarium in San Francisco, California. She was released because she would not eat and constantly bumped against the walls.[72]
Shark tourism

Photo of man dropping chum off the side of a boat

 Putting chum in the water


 A great white shark approaches divers in a cage off Dyer Island, Western Cape, South Africa.

File:Great white shark and cage diving 2.wmv.OGG
Play media


 A great white shark approaches a cage
Cage diving is most common at sites where great whites are frequent including the coast of South Africa, the Neptune Islands in South Australia,[73] and Guadalupe Island in Baja California. Cage diving and swimming with sharks is a focus for a booming tourist industry due to its popularity.[74][75] A common practice is to chum the water with pieces of fish to attract the sharks. These practices may make sharks more accustomed to people in their environment and to associate human activity with food; a potentially dangerous situation. By drawing bait on a wire towards the cage, tour operators lure the shark to the cage, possibly striking it, exacerbating this problem. Other operators draw the bait away from the cage, causing the shark to swim past the divers.
At present, hang baits are illegal off Isla Guadalupe and reputable dive operators do not use them. Operators in South Africa and Australia continue to use hang baits and pinniped decoys.[76] In South Australia, playing rock music recordings underwater, including the AC/DC album Back in Black has also been used experimentally to attract sharks.[77]
Companies object to being blamed for shark attacks, pointing out that lightning tends to strike humans more often than sharks bite humans.[78] Their position is that further research needs to be done before banning practices such as chumming, which may alter natural behavior.[79] One compromise is to only use chum in areas where whites actively patrol anyway, well away from human leisure areas. Also, responsible dive operators do not feed sharks. Only sharks that are willing to scavenge follow the chum trail and if they find no food at the end then the shark soon swims off and does not associate chum with a meal. It has been suggested that government licensing strategies may help enforce these suggested advisories.[76]
The shark tourist industry has some financial leverage in conserving this animal. A single set of great white jaws can fetch a one-time price of up to £20,000. However, that is a fraction of the tourism value of a live shark, a more sustainable economic activity. For example, the dive industry in Gansbaai, South Africa, consists of six boat operators with each boat guiding 30 people each day. With fees between £50 to £150 per person, a single live shark that visits each boat can create anywhere between £9,000 and £27,000 of revenue daily.[80]
Conservation status
It is unclear how much of a concurrent increase in fishing for great white sharks has caused the decline of great white shark populations from the 1970s to the present. No accurate global population numbers are available, but the great white shark is now considered vulnerable.[2] Sharks taken during the long interval between birth and sexual maturity never reproduce, making population recovery and growth difficult.
The IUCN notes that very little is known about the actual status of the great white shark, but as it appears uncommon compared to other widely distributed species, it is considered vulnerable.[2] It is included in Appendix II of CITES,[13] meaning that international trade in the species requires a permit.[81] As of March 2010, it has also been included in Annex I of the CMS Migratory Sharks MoU, which strives for increased international understanding and coordination for the protection of certain migratory sharks.[82] A February 2010 study by Barbara Block of Stanford University estimated the world population of great white sharks to be lower than 3,500 individuals, making the species more vulnerable to extinction than the tiger, whose population is in the same range.[83]
Fishermen target many sharks for their jaws, teeth, and fins, and as game fish in general. The great white shark, however, is rarely an object of commercial fishing, although its flesh is considered valuable. If casually captured (it happens for example in some tonnare in the Mediterranean), it is misleadingly sold as smooth-hound shark.
In Australia
The great white shark was declared as Vulnerable by the Australian Government in 1999 due to significant population decline and is currently protected under the Environmental Protection and Biodiversity Conservation (EPBC) Act.[84] The causes of decline prior to protection included mortality from sport fishing harvests as well as being caught in beach protection netting.[85]
The national conservation status of the great white shark is reflected by all Australian states under their respective laws, granting the species full protection throughout Australia regardless of jurisdiction.[84] In fact, many states had prohibited the killing or possession of great white sharks prior to national legislation coming into effect. The great white shark is further listed as Threatened in Victoria under the Flora and Fauna Guarantee Act, and as rare or likely to become extinct under Schedule 5 of the Wildlife Conservation Act in Western Australia.[84]
In 2002, the Australian government created the White Shark Recovery Plan, implementing government-mandated conservation research and monitoring for conservation in addition to federal protection and stronger regulation of shark-related trade and tourism activities.[85] An updated recovery plan was published in 2013 to review progress, research findings, and to implement further conservation actions.[86] A study in 2012 revealed that Australia's White Shark population was separated by Bass Strait into genetically distinct eastern and western populations, indicating a need for the development of regional conservation strategies.[87]
Presently, human-caused shark mortality is continuing, primarily from accidental and illegal catching in commercial and recreational fishing as well as from being caught in beach protection netting, and the populations of great white shark in Australia are yet to recover.[86]
In New Zealand
As of April 2007, great white sharks were fully protected within 370 kilometres (200 nmi) of New Zealand and additionally from fishing by New Zealand-flagged boats outside this range. The maximum penalty is a $250,000 fine and up to six months in prison.[88]
In North America
In 2013, great white sharks were added to California's Endangered Species Act. From data collected, the population of great whites in the North Pacific is estimated to be fewer than 340 individuals. Research also reveals these sharks are genetically distinct from other members of their species elsewhere in Africa, Australia, and the east coast of North America, having been isolated from other populations.[89]
A 2014 study estimated the population of great white sharks along the California coastline to be approximately 2,400.[90][91]
See also

Portal icon Sharks portal
Outline of sharks
List of sharks
Megalodon
References
1.^ Jump up to: a b Gottfried, M. D.; Fordyce, R. E. (2001). "An associated specimen of Carcharodon angustidens (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on Carcharodon interrelationships". Journal of Vertebrate Paleontology 21 (4): 730–739. doi:10.1671/0272-4634(2001)021[0730:AASOCA]2.0.CO;2.
2.^ Jump up to: a b c d Fergusson, I., Compagno, L.; Marks, M. (2000). "Carcharodon carcharias in IUCN 2012". IUCN Red List of Threatened Species, Vers. 2009.1. International Union for Conservation of Nature and Natural Resources. Retrieved 28 October 2009. (Database entry includes justification for why this species is vulnerable)
3.^ Jump up to: a b Taylor, Leighton R. (1 January 1993). Sharks of Hawaii: Their Biology and Cultural Significance. University of Hawaii Press. p. 65. ISBN 978-0-8248-1562-2.
4.^ Jump up to: a b c Tricas, T. C.; McCosker, J. E. (12 July 1984). "Predatory behaviour of the white shark (Carcharodon carcharias), with notes on its biology". Proceedings of the California Academy of Sciences (California Academy of Sciences) 43 (14): 221–238. Retrieved 22 January 2013.
5.^ Jump up to: a b c d Wroe, S.; Huber, D. R.; Lowry, M.; McHenry, C.; Moreno, K.; Clausen, P.; Ferrara, T. L.; Cunningham, E.; Dean, M. N.; Summers, A. P. (2008). "Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?". Journal of Zoology 276 (4): 336–342. doi:10.1111/j.1469-7998.2008.00494.x.
6.^ Jump up to: a b "Great White Shark". National Geographic. Retrieved 24 July 2010.
7.^ Jump up to: a b c Viegas, Jennifer. "Largest Great White Shark Don't Outweigh Whales, but They Hold Their Own". Discovery Channel. Retrieved 19 January 2010.
8.^ Jump up to: a b http://www.sciencedaily.com/releases/2014/01/140109004145.htm
9.Jump up ^ Alaska's Great White Sharks, by Bruce A. Wright, 2007, page 27
10.Jump up ^ Currents of Contrast: Life in Southern Africa's Two Oceans. Struik. 2005. pp. 31–. ISBN 978-1-77007-086-8.
11.Jump up ^ Knickle, Craig. "Tiger Shark". Florida Museum of Natural History Ichthyology Department. Archived from the original on 7 July 2013. Retrieved 2 July 2009.
12.Jump up ^ "ISAF Statistics on Attacking Species of Shark". Florida Museum of Natural History University of Florida. Retrieved 4 May 2008.
13.^ Jump up to: a b "Carcharodon carcharias". UNEP-WCMC Species Database: CITES-Listed Species On the World Wide Web. Archived from the original on 15 June 2013. Retrieved 8 April 2010.
14.Jump up ^ Hile, Jennifer (23 January 2004). "Great White Shark Attacks: Defanging the Myths". Marine Biology. National Geographic. Archived from the original on 26 April 2009. Retrieved 2 May 2010.
15.^ Jump up to: a b ISAF Statistics on Attacking Species of Shark
16.Jump up ^ "The Great White Shark". The Enviro Facts Project. Archived from the original on 13 June 2009. Retrieved 9 July 2007.
17.Jump up ^ "New Ancient Shark Species Gives Insight Into Origin of Great White". sciencedaily.com. University of Florida. 14 November 2012.
18.Jump up ^ Kevin G. N., Charles N. C., Gregory A. W. (2006). [Archive copy at the Wayback Machine Tracing the ancestry of the great white shark] (PDF). Retrieved 25 December 2007.
19.Jump up ^ "Areal Distribution of the White Shark". National Capital Freenet. Retrieved 16 October 2010.
20.^ Jump up to: a b Thomas, Pete (5 April 2010). "Great white shark amazes scientists with 4000-foot dive into abyss". GrindTV. Archived from the original on 17 August 2012.
21.Jump up ^ "South Africa – Australia – South Africa". "White Shark Trust".
22.Jump up ^ Thomas, Pete (29 September 2006). "The Great White Way". "Los Angeles Times". Retrieved 1 October 2006.
23.^ Jump up to: a b "Great White Sharks, Carcharodon carcharias at MarineBio.org". Marin Bio. Retrieved 20 August 2012.
24.Jump up ^ Echenique, E. J. "A Shark to Remember: The Story of a Great White Caught in 1945". Archived from the original on 27 April 2012. Retrieved 22 January 2013. Home Page of Henry F. Mollet, Research Affiliate, Moss Landing Marine Laboratories.
25.^ Jump up to: a b c Ellis, Richard and John E. McCosker. 1995. Great White Shark. Stanford University Press, ISBN 0-8047-2529-2
26.^ Jump up to: a b Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. ISBN 978-0-85112-235-9.
27.^ Jump up to: a b Mollet, H. F. (2008) White Shark Summary Carcharodon carcharias (Linnaeus, 1758). Home Page of Henry F. Mollet, Research Affiliate, Moss Landing Marine Laboratories.
28.^ Jump up to: a b c d "Size and age of the white pointer shark, Carcharodon carcharias (Linnaeus)". Archived from the original on 4 March 2012. Retrieved 27 September 2006.
29.^ Jump up to: a b c d e f g h i j k l m n Klimley, Peter; Ainley, David (1996). Great White Sharks: The Biology of Carcharodon carcharias. Academic Press. pp. 91–108. ISBN 0-12-415031-4.
30.Jump up ^ "Huge 'White Pointer' Encounter". Archived from the original on 17 April 2012. Retrieved 20 January 2010.
31.Jump up ^ "Summary of Large Tiger Sharks Galeocerdo cuvier (Peron & LeSueur, 1822)". Archived from the original on 10 April 2012. Retrieved 3 May 2010.
32.Jump up ^ Eagle, Dane. "Greenland Shark". Florida Museum of Natural History. Retrieved 1 September 2012.
33.Jump up ^ Martin, R. Aidan. "Pacific Sleeper Shark". ReefQuest Centre for Shark Research. Biology of Sharks and Rays. Archived from the original on 20 April 2013. Retrieved 1 September 2012.
34.Jump up ^ "The physiology of the ampullae of Lorenzini in sharks". Biology Dept., Davidson College. Biology @ Davidson. Retrieved 20 August 2012.
35.Jump up ^ Martin, R. Aidan. "Body Temperature of the Great white and Other Lamnoid Sharks". ReefQuest Centre for Shark research. Retrieved 16 October 2010.
36.Jump up ^ Barber, Elizabeth (18 July 2013). "Great white shark packs its lunch in its liver before a big trip". The Christian Science Monitor. Archived from the original on 2 August 2013.
37.Jump up ^ Jordan, Rob (17 July 2013). "Great White Sharks' Fuel for Oceanic Voyages: Liver Oil". sciencedaily.com. Stanford University.
38.Jump up ^ Medina, Samantha (27 July 2007). "Measuring the great white's bite". Cosmos Magazine. Retrieved 1 September 2012.
39.^ Jump up to: a b c d e f Martin, R. Aidan and Martin, Anne. "Sociable Killers". Natural History Magazine, Inc. Archived from the original on 15 May 2013. Retrieved 30 September 2006.
40.Jump up ^ Johnson, R. L.; Venter, A.; Bester, M.N. and Oosthuizen, W.H. (2006). "Seabird predation by white shark Carcharodon Carcharias and Cape fur seal Arctocephalus pusillus pusillus at Dyer Island". South African Journal of Wildlife Research (South Africa) 36 (1): 23–32.
41.Jump up ^ Estrada, J. A.; Rice, Aaron N.; Natanson, Lisa J. and Skomal, Gregory B. (2006). "Use of isotopic analysis of vertebrae in reconstructing ontogenetic feeding ecology in white sharks". Ecology (USA) 87 (4): 829–834. doi:10.1890/0012-9658(2006)87[829:UOIAOV]2.0.CO;2. PMID 16676526.
42.Jump up ^ "Catch as Catch Can". ReefQuest Centre for Shark Research. Retrieved 16 October 2010.
43.Jump up ^ "How Fast Can a Shark Swim?". ReefQuest Centre for Shark Research.
44.Jump up ^ "White Shark Predatory Behavior at Seal Island". ReefQuest Centre for Shark Research.
45.Jump up ^ Martin, Rick. "Predatory Behavior of Pacific Coast White Sharks". Shark Research Committee.
46.^ Jump up to: a b c d e f g Heithaus, Michael (2001). "Predator–prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review". Journal of Zoology (London: Cambridge University Press) 253: 53–68. doi:10.1017/S0952836901000061. Retrieved 26 February 2010.
47.Jump up ^ Long, Douglas (1991). "Apparent Predation by a White Shark Carcharodon carcharias on a Pygmy Sperm Whale Kogia breviceps". Fishery Bulletin 89: 538–540.
48.Jump up ^ "Monster shark bites great white in half". The Daily Telegraph (Australia). 27 October 2009.
49.Jump up ^ Dudley, Sheldon F. J.; Anderson-Reade, Michael D.; Thompson, Greg S. and McMullen, Paul B. (2000). "Concurrent scavenging off a whale carcass by great white sharks, Carcharodon carcharias, and tiger sharks, Galeocerdo cuvier" (PDF). Marine Biology. Fishery Bulletin. Retrieved 4 May 2010.
50.Jump up ^ "Great White Shark Feeding On Whale Carcass". wn.com.
51.Jump up ^ "Natural History of the White Shark". PRBO Conservation Science. 2 May 2010. Archived from the original on 3 July 2013.
52.Jump up ^ "Carcharodon carcharias, Great White Sharks". marinebio.org.
53.Jump up ^ "Brief Overview of the Great White Shark (Carcharodon carcharias)". Elasmo Research. Retrieved 20 August 2012.
54.Jump up ^ Martin, R. Aidan. "White Shark Breaching". ReefQuest Centre for Shark Research. Retrieved 18 April 2012.
55.Jump up ^ Martin, R. A.; Hammerschlag, N.; Collier, R. S.; Fallows, C. (2005). "Predatory behaviour of white sharks (Carcharodon carcharias) at Seal Island, South Africa". Journal of the Marine Biological Association of the UK 85 (5): 1121. doi:10.1017/S002531540501218X. edit
56.Jump up ^ Rice, Xan (19 July 2011). "Great white shark jumps from sea into research boat". The Guardian (London: Guardian Media Group). Retrieved 20 July 2011. "Marine researchers in South Africa had a narrow escape after a three-metre-long great white shark breached the surface of the sea and leapt into their boat, becoming trapped on deck for more than an hour. [...] Enrico Gennari, an expert on great white sharks, [...] said it was almost certainly an accident rather than an attack on the boat."
57.^ Jump up to: a b Pyle, Peter; Schramm, Mary Jane; Keiper, Carol and Anderson, Scot D. (26 August 2006). "Predation on a white shark (Carcharodon carcharias) by a killer whale (Orcinus orca) and a possible case of competitive displacement". Society of marine mammalogy (USA: Marine Mammal Science) 15 (2): 563–568. doi:10.1111/j.1748-7692.1999.tb00822.x. Archived from the original on 22 March 2012. Retrieved 8 May 2010.
58.^ Jump up to: a b "Nature Shock Series Premiere: The Whale That Ate the Great White". Tvthrong.co.uk. 4 October 1997. Retrieved 16 October 2010.
59.Jump up ^ "Killer Whale Documentary Part 4". youtube.com.
60.^ Jump up to: a b c Turner, Pamela S. (Oct–Nov 2004). "Showdown at Sea: What happens when great white sharks go fin-to-fin with killer whales?". National Wildlife (National Wildlife Federation) 42 (6). Archived from the original on 16 January 2011. Retrieved 21 November 2009.
61.Jump up ^ Benchley, Peter (April 2000). "Great white sharks". National Geographic: 12. ISSN 0027-9358. "considering the knowledge accumulated about sharks in the last 25 years, I couldn't possibly write Jaws today ... not in good conscience anyway ... back then, it was OK to demonize an animal."
62.Jump up ^ McCabe, Meghan (2000). "Sharks: Killing Machines?".
63.Jump up ^ Tricas, T.C.; McCosker, John (1984). "Proceedings of the California Academy of Sciences". Predatory behavior of the white shark, Carcharodon carcharias, and notes on its biology 43 (14): 221–238.
64.Jump up ^ "ISAF Statistics for Worldwide Unprovoked White Shark Attacks Since 1990". 10 February 2011. Retrieved 19 August 2011.
65.Jump up ^ "Unprovoked White Shark Attacks on Kayakers". Shark Research Committee. Retrieved 14 September 2008.
66.Jump up ^ Tricas, Timothy C.; McCosker, John E. (1984). "Predatory Behaviour of the White Shark (Carcharodon carcharias), with Notes on its Biology". Proceedings of the California Academy of Sciences 43 (14): 221–238.
67.Jump up ^ "Great white shark sets record at California aquarium". USA Today. 2 October 2004. Retrieved 27 September 2006.
68.Jump up ^ Gathright, Alan (16 September 2004). "Great white shark puts jaws on display in aquarium tank". San Francisco Chronicle. Retrieved 27 September 2006.
69.Jump up ^ "White Shark Research Project". Monterey Bay Aquarium. Retrieved 27 September 2006.
70.Jump up ^ Squatriglia, Chuck (1 September 2003). "Great white shark introduced at Monterey Bay Aquarium". San Francisco Chronicle. Retrieved 27 September 2006.
71.Jump up ^ "Learn All About Our New White Shark". "Monterey Bay Aquarium". Retrieved 28 August 2009.
72.Jump up ^ "Electroreception". Elasmo-research. Retrieved 27 September 2006.
73.Jump up ^ "Shark cage diving". Department of Environment, Water and Natural Resources. Archived from the original on 9 April 2013. Retrieved 11 March 2013.
74.Jump up ^ Squires, Nick (18 January 1999). "Swimming With Sharks". BBC. Archived from the original on 17 August 2003. Retrieved 21 January 2010.
75.Jump up ^ Simon, Bob (11 December 2005). "Swimming With Sharks". 60 Minutes. Retrieved 22 January 2010.
76.^ Jump up to: a b "Blue Water Hunting Successfully". Blue Water Hunter. Archived from the original on 18 August 2012. Retrieved 20 August 2012.
77.Jump up ^ "A Great white shark's favorite tune? 'Back in Black'" Surfersvillage Global Surf News (2011-06-03). Retrieved 2014-01-30.
78.Jump up ^ "Shark Attacks Compared to Lightning". Florida Museum of Natural History. 18 July 2003. Retrieved 7 November 2006.
79.Jump up ^ Hamilton, Richard (15 April 2004). "SA shark attacks blamed on tourism". BBC. Archived from the original on 23 March 2012. Retrieved 24 October 2006.
80.Jump up ^ "White Shark Manifesto-kelp Forests". World News. Retrieved 20 August 2012.
81.Jump up ^ "Regulation of Trade in Specimens of Species Included in Appendix II". CITES (1973). Archived from the original on 17 July 2011. Retrieved 8 April 2012.
82.Jump up ^ "Memorandum of Understanding on the Conservation of Migratory Sharks". Convention on Migratory Species. 12 February 2010. Archived from the original on 20 April 2013. Retrieved 31 August 2012.
83.Jump up ^ Sample, Ian (19 February 2010). "Great white shark is more endangered than tiger, claims scientist". The Guardian. Retrieved 14 August 2013.
84.^ Jump up to: a b c Government of Australia. "Species Profile and Threats Database – Carcharodon carcharias — Great White Shark". Retrieved 21 August 2013.
85.^ Jump up to: a b Environment Australia (2002). White Shark (Carcharodon carcharias) Recovery Plan (Report).
86.^ Jump up to: a b Government of Australia Department of Sustainability, Environment, Water, Population and Communities (2013). Recovery Plan for the White Shark (Carcharodon carcharias) (Report).
87.Jump up ^ Blower, Dean C.; Pandolfi, John M.; Bruce, Barry D.; Gomez-Cabrera, Maria del C.; Ovenden, Jennifer R. (2012). "Population genetics of Australian white sharks reveals fine-scale spatial structure, transoceanic dispersal events and low effective population sizes". Marine Ecology Progress Series 455: 229–244. doi:10.3354/meps09659.
88.Jump up ^ "Great white sharks to be protected". New Zealand Herald. 30 November 2006. Retrieved 30 November 2006.
89.Jump up ^ Quan, Kristene (4 March 2013). "Great White Sharks Are Now Protected under California Law". time.com.
90.Jump up ^ Williams, Lauren (July 3, 2014). "Shark numbers not tanking". Huntington Beach Wave (The Orange County Register). p. 12.
91.Jump up ^ Burgess, George H.; Bruce, Barry D.; Cailliet, Gregor M.; Goldman, Kenneth J.; Grubbs, R. Dean; Lowe, Christopher J.; MacNeil, M. Aaron; Mollet, Henry F.; Weng, Kevin C.; O'Sullivan, John B. (June 16, 2014). "A Re-Evaluation of the Size of the White Shark (Carcharodon carcharias) Population off California, USA". PLOS ONE. doi:10.1371/journal.pone.0098078. Retrieved 9 July 2014.
External links
 Wikimedia Commons has media related to Carcharodon carcharias.
 Wikispecies has information related to: Carcharodon carcharias
News and articles
Ocean Portal: Great White Shark, "Cool Stuff," Life and Natural History, Science, Human Connections, and Educator Resources by The Smithsonian Institution, 2010
Great White Shark: Fact File from National Geographic
Most Complete Great White Fossil Yet by National Geographic
Great White Shark Filmed Breaching at Night by National Geographic
In-depth article: Shark's Super Senses from the PBS Ocean Adventures site
Are great whites descended from mega-sharks? from LiveScience
"Great White Sharks – The Truth" by documentary maker Carly Maple – Australian focus
White Shark Biological Profile from Florida Museum of Natural History
Great White Shark (Carcharodon carcharias) – Legal Status
Leviathans may battle in remote depths from Los Angeles Times
Article on largest Great Whites Recorded
Huge great white cruises off busy beach
Photographic depictions and tagging activities
ARKive – Images and movies of the great white shark, Carcharodon carcharias
Photo Gallery: Great White Sharks from National Geographic
Pictures of great white sharks
TOPP, Tagging of Pacific Predators, a research group that tags and studies the habits and migration of the white shark.
Videos
Nature's Perfect Predator – Great White Shark from Discovery Channel
White Shark Cage Dive in Gansbaai, South Africa on YouTube
Riding a Great White from Discovery Channel
Wild – The Whale That Ate Jaws on YouTube (This video is about a documented interaction of an Orca with an inexperienced white shark)


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Categories: IUCN Red List vulnerable species
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Megafauna of Africa
Megafauna of Australia
Megafauna of Eurasia
Megafauna of North America
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Megalodon
From Wikipedia, the free encyclopedia
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For other uses, see Megalodon (disambiguation).
"Carcharocles" redirects here.
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Megalodon
Temporal range: Late Oligocene-Early Pleistocene, 28–1.5Ma
PreЄ
Є
O
S
D
C
P
T
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Megalodon shark jaws museum of natural history 068.jpg
Model of the jaws of megalodon at the American Museum of Natural History.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Selachimorpha
Order: Lamniformes
Family: Disputed; Lamnidae or †Otodontidae
Genus: Disputed; Carcharodon or †Carcharocles
Species: †C. megalodon
Binomial name
Disputed; Carcharodon megalodon or Carcharocles megalodon
For Carcharodon megalodon, Agassiz, 1843
Synonyms
Procarcharodon megalodon Casier, 1960
Megaselachus megalodon Glikman, 1964

Megalodon (/ˈmɛɡələdɒn/ MEG-ə-lə-don; meaning "big tooth", from Ancient Greek: μέγας (megas) “big, mighty” + ὀδόν (odon) (from ὀδούς (odous) "tooth")),[1] is an extinct species of shark that lived approximately 28 to 1.5 million years ago, during the Cenozoic Era (late Oligocene to early Pleistocene).
The taxonomic assignment of C. megalodon has been debated for nearly a century, and is still under dispute. The two major interpretations are Carcharodon megalodon (under family Lamnidae) or Carcharocles megalodon (under the family Otodontidae).[2] Consequently, the scientific name of this species is commonly abbreviated C. megalodon in the literature.
C. megalodon is regarded as one of the largest and most powerful predators in vertebrate history,[3] and likely had a profound impact on the structure of marine communities.[4] Fossil remains suggest that this giant shark reached a maximum length of 14–18 metres (46–59 ft),[3] and also affirm that it had a cosmopolitan distribution.[2] Scientists suggest that C. megalodon looked like a stockier version of the great white shark, Carcharodon carcharias.[5]


Contents  [hide]
1 Discovery 1.1 Glossopetrae
1.2 Identification
2 Fossils 2.1 Teeth
2.2 Vertebrae
2.3 Distribution and age
3 Taxonomy and evolution 3.1 Megalodon within Carcharodon
3.2 Megalodon within Carcharocles


3.3 Considerations
4 Anatomy 4.1 Size estimation







4.2 Dentition and jaw mechanics

4.3 Skeletal anatomy

5 Paleoecological considerations 5.1 Range and habitat
5.2 Prey relationships
5.3 Feeding strategies
5.4 Nursery areas
6 Extinction 6.1 Oceanic cooling and sea level drops
6.2 Decline in food supply
6.3 New competition
7 In fiction
8 See also
9 Footnotes
10 References
11 External links 11.1 Paleontological videos

Discovery
Glossopetrae



 The depiction of a shark's head by Nicolaus Steno in his work, The Head of a Shark Dissected.
According to Renaissance accounts, gigantic, triangular fossil teeth often found embedded in rocky formations were once believed to be the petrified tongues, or glossopetrae, of dragons and snakes. This interpretation was corrected in 1667 by Danish naturalist Nicolaus Steno, who recognized them as shark teeth, and famously produced a depiction of a shark's head bearing such teeth.[6] He described his findings in the book The Head of a Shark Dissected, which also contained an illustration of a C. megalodon tooth.[7]
Identification
Swiss naturalist Louis Agassiz gave the shark its initial scientific name, Carcharodon megalodon, in 1835,[8] in his research work Recherches sur les poissons fossiles[9] (Research on fossil fish), which he completed in 1843. Megalodon teeth are morphologically similar to the teeth of the great white shark. On the basis of this observation, Agassiz assigned megalodon to the genus Carcharodon.[8] While the scientific name is C. megalodon, it is often informally dubbed the "megatooth shark",[5] "giant white shark"[10] or "monster shark".[11]
Fossils
C. megalodon is represented in the fossil record primarily by teeth and vertebral centra.[5] As with all sharks, C. megalodon's skeleton was formed of cartilage rather than bone; this results in mostly poorly preserved fossil specimens.[12]
Teeth



 Megalodon tooth with slant height (diagonal length) of over 170 mm.


 Megalodon tooth with two great white shark teeth.
The most common megalodon fossils are its teeth. Diagnostic characteristics include: triangular shape,[2] robust structure,[5] large size,[2] fine serrations,[2] and visible v-shaped neck.[2] Megalodon teeth can measure over 180 millimetres (7.1 in) in slant height or diagonal length, and are the largest in size of any known shark species.[13]
Vertebrae
Some fossil vertebrae have been found.[7] The most notable example is a partially preserved vertebral column of a single specimen, excavated in the Antwerp basin, Belgium by M. Leriche in 1926. It comprises 150 vertebral centra, with the centra ranging from 55 millimetres (2.2 in) to 155 millimetres (6.1 in) in diameter.[5] However, scientists have claimed that considerably larger vertebral centra can be expected.[5] A partially preserved vertebral column of another megalodon specimen was excavated from Gram clay, Denmark by Bendix-Almgeen in 1983. This specimen comprises 20 vertebral centra, with the centra ranging from 100 millimetres (3.9 in) to 230 millimetres (9.1 in) in diameter.[14]
Distribution and age



 Megalodon tooth excavated from Lee Creek Mine, Aurora, North Carolina, United States.
C. megalodon fossils have been excavated from many parts of the world, including Europe, Africa and both North and South America,[5][7] as well as Puerto Rico,[15] Cuba,[16] Jamaica,[17] Canary Islands,[18] Australia,[19] New Zealand,[13] Japan,[5][7] Malta,[13] Grenadines[20] and India.[7] Megalodon teeth have been excavated from regions far away from continental lands, such as the Mariana Trench in the Pacific Ocean.[13]
The earliest megalodon remains were reported from late Oligocene strata, circa 28 million years old.[21][22] Although fossils are mostly absent in strata extending beyond the Tertiary boundary,[5] they have been reported from subsequent Pleistocene strata.[23] It is believed that C. megalodon became extinct in the Pleistocene, probably about 1.5 million years ago.[12]
Taxonomy and evolution
Even after decades of research and scrutiny, controversy over C. megalodon phylogeny persists.[8][24] Several shark researchers (e.g. J. E. Randall, A. P. Klimley, D. G. Ainley, M. D. Gottfried, L. J. V. Compagno, S. C. Bowman, and R. W. Purdy) insist that C. megalodon is a close relative of the great white shark. However, others (e.g. D. S. Jordan, H. Hannibal, E. Casier, C. DeMuizon, T. J. DeVries, D. Ward, and H. Cappetta) cite convergent evolution as the reason for the dental similarity. Such Carcharocles advocates have gained noticeable support.[25] However, the original taxonomic assignment still has wide acceptance.[8]
Megalodon within Carcharodon



Lamniformes 



I. hastalis



Sacaco sp.








C. carcharias



C. megalodon






The megalodon hypothesis claims that C. carcharias is more closely related to C. megalodon than I. hastalis.[8]

Lamniformes 



O. obliquus








I. hastalis






C. carcharias



C. megalodon






The alternative Otodus-origin hypothesis claims that C. carcharias descends from megatoothed sharks.[24]
The traditional view is that megalodon should be classified within the genus Carcharodon along with the great white shark. The main reasons cited for this phylogeny are: (1) an ontogenetic gradation, whereby the teeth shift from coarse serrations as a juvenile to fine serrations as an adult, the latter resembling megalodon's; (2) morphological similarity of teeth of young megalodon to those of C. carcharias; (3) a symmetrical second anterior tooth; (4) large intermediate tooth that is inclined mesially; and (5) upper anterior teeth that have a chevron-shaped neck area on the lingual surface. Carcharodon supporters suggest that megalodon and C. carcharias share a common ancestor, Palaeocarcharodon orientalis.[8][13]
Megalodon within Carcharocles



Lamniformes 


I. hastalis




Sacaco sp.



C. carcharias






void
C. megalodon




The hastalis hypothesis claims that C. carcharias is more closely related to I. hastalis than to C. megalodon.[8]

Lamniformes 



O. obliquus



C. megalodon








I. hastalis



C. carcharias






The Isurus-origin hypothesis claims that C. carcharias descends from I. hastalis.[24]
Around 1923, the genus Carcharocles was proposed by D. S. Jordan and H. Hannibal, to classify the shark C. auriculatus. Later on, Carcharocles proponents assigned megalodon to Carcharocles.[8][13] Carcharocles proponents also suggest that the direct ancestor of the sharks belonging to Carcharocles is an ancient giant shark called Otodus obliquus, which lived during the Paleocene and Eocene epochs.[24][25] According to Carcharocles supporters, Otodus obliquus evolved into Otodus aksuaticus, which evolved into Carcharocles auriculatus, and then into Carcharocles angustidens, and then into Carcharocles chubutensis, and then into megalodon. Hence, the immediate ancestor of C. megalodon is C. chubutensis, because it serves as the missing link between C. augustidens and C. megalodon and it bridges the loss of the "lateral cusps" that characterize megalodon.[13][25]
Reconsideration of megatooth lineage from Carcharocles to Otodus
Shark researchers are apparently reconsidering the genus of entire Carcharocles lineage back to Otodus.[26][27]
Megalodon as a chronospecies
Shark researcher David Ward elaborated on the evolution of Carcharocles by implying that this lineage, stretching from the Paleocene to the Pliocene, is of a single giant shark which gradually changed through time, suggesting a case of chronospecies.[13] This assessment may have credibility.[27]
Mako sharks as closest relatives of great whites
Carcharocles proponents point out that the great white shark is closely related to an ancient shark Isurus hastalis, the "broad tooth mako", rather than to megalodon. One reason cited by paleontologist Chuck Ciampaglio is that the dental morphometrics (variations and changes in the physical form of objects) of I. hastalis and C. carcharias are remarkably similar. Another reason cited is that megalodon teeth have much finer serrations than C. carcharias teeth.[8] Further evidence linking the great white shark more closely to ancient mako sharks, rather than to megalodon, was provided in 2009 — the fossilized remains of a form of the great white shark about 4 million years old were excavated from southwestern Peru in 1988. These remains demonstrate a likely shared ancestor of modern mako and great whites.[24][28]
Considerations



 Two teeth of great white shark (white) compared to a single tooth of megalodon (black). A coin 23 mm in width shows the scale.
Ciampaglio asserted that dental similarities between megalodon and the great white are superficial with noticeable morphometric differences between them, and that these findings are sufficient to warrant a separate genus.[8][11] However, some Carcharodon proponents (i.e., M. D. Gottfried, and R. E. Fordyce) provided more arguments for a close relationship between the megatooth and the great white.[22] With respect to the recent controversy regarding fossil lamnid shark relationships, overall morphology – particularly the internal calcification patterns – of the great white shark vertebral centra have been compared to well-preserved fossil centra from the megatooth, including megalodon and C. angustidens. The morphological similarity of these comparisons supports a close relationship of the giant fossil megatooth species to extant whites.[22][29]
Gottfried and Fordyce pointed out that some great white shark fossils are about 16 million years old and predate the transitional Pliocene fossils.[22] In addition the Oligocene megalodon records[13][22] contradict the suggestion that C. chubutensis is the immediate ancestor of C. megalodon. These records also indicate that megalodon co-existed with C. angustidens.[22]
Some paleontologists argue that the genus Otodus should be used for sharks within the Carcharocles lineage and the genus Carcharocles should be discarded.[2]
Several Carcharocles proponents (i.e. C. Pimiento, D. J. Ehret, B. J. MacFadden, and G. Hubbell) claim that both species belong to the order Lamniformes and in the absence of living members of the family Otodontidae, the great white shark is the species most ecologically analogous to megalodon.[2]
Anatomy
Among extant species, the great white shark is regarded as the best analogue to megalodon.[2] The lack of well-preserved fossil megalodon skeletons led scientists to rely on the great white shark as the basis of its reconstruction and size estimation.[5]
Size estimation
Due to fragmentary remains, estimating the size of C. megalodon has been challenging.[13] However, the scientific community has concluded that C. megalodon was larger than the whale shark, Rhincodon typus. Scientists focused on two aspects of size: total length and body mass.
Length



 Reconstruction by Bashford Dean in 1909,[30] with fossil teeth assembled from various localities.
The first attempt to reconstruct a megalodon jaw was made by Bashford Dean in 1909. From the dimensions of this jaw reconstruction, it was hypothesized that C. megalodon could have approached 30 metres (98 ft).[30] Better knowledge of dentition and more accurate muscle structures,[30] led to a rectified version of Dean's jaw model about 70 percent of its original size and to a size consistent with modern findings.[30] To resolve such errors, scientists, aided by new fossil discoveries of C. megalodon and improved knowledge of its closest living analogue's anatomy, introduced more quantitative methods for estimating its size based on the statistical relationships between the tooth sizes and body lengths.[5][30] Some methods are mentioned below.
Enamel height
In 1973, Hawaiian ichthyologist John E. Randall used a plotted graph to demonstrate a relationship between the enamel height (the vertical distance of the blade from the base of the enamel portion of the tooth to its tip) of the largest tooth in the upper jaw of the great white shark and its total length.[30][31] Randall extrapolated this method to estimate C. megalodon's total length. Randall cited two megalodon teeth in his work, specimen number 10356 at the American Museum of Natural History and specimen number 25730 at the United States National Museum, which had enamel heights of 115 millimetres (4.5 in) and 117.5 millimetres (4.63 in) respectively.[31] These teeth yielded a corresponding total length of about 13 metres (43 ft).[30][31] In 1991, Richard Ellis and John E. McCosker claimed that tooth enamel height does not necessarily increase in proportion to the animal's total length.[5]
Largest anterior tooth height
In 1996, after scrutiny of 73 great white shark specimens, Michael D. Gottfried, Leonard Compagno and S. Curtis Bowman proposed a linear relationship between the height of the largest upper anterior tooth and total length in the great white shark. The proposed relationship is: total length in metres = − (0.096) × [UA maximum height (mm)]-(0.22).[5][22] Gottfried and colleagues then extrapolated their technique to C. megalodon. The biggest megalodon tooth in the possession of this team was an upper second anterior specimen, whose maximum height was 168 millimetres (6.6 in). This tooth had been discovered by Compagno in 1993. It yielded an estimated total length of 15.9 metres (52 ft).[5] Rumors of larger megalodon teeth persisted at the time.[5] The maximum tooth height for this method is measured as a vertical line from the tip of the crown to the bottom of the lobes of the root, parallel to the long axis of the tooth.[5] In layman's terms, the maximum height of the tooth is its slant height.[32]
Root width
In 2002, shark researcher Clifford Jeremiah proposed that total length was proportional to the root width of an upper anterior tooth. He claimed that for every 1 centimetre (0.39 in) of width, there is approximately 4.5 feet (1.4 m) of the shark. Jeremiah pointed out that the jaw perimeter of a shark is directly proportional to its total length, with the width of the roots of the largest teeth being a proxy for estimating jaw perimeter. The largest tooth in the possession of Jeremiah had a root width of about 12 centimetres (4.7 in), which yielded 16.5 metres (54 ft) total length. Ward asserted that this method is based on a sound principle that works well with most large sharks.[13]
Crown height
In 2002, paleontologist Kenshu Shimada of DePaul University proposed a linear relationship between tooth crown height and total length in great white sharks after conducting anatomical analysis of several specimens.[33] This relationship is expressed as: total length in centimetres = a + bx, where a is a constant, b is the slope of the line and x is the crown height of tooth in millimetres. This relationship allowed any tooth to be used for the estimate.[2][33] The crown height was measured as maximum vertical enameloid height on the labial side. Shimada pointed out that previously proposed methods were based on weaker evaluation of dental homology, and that the growth rate between the crown and root is not isometric, which he considered in his model.[33] Furthermore, this relationship could be used to predict the total length of sharks that are morphologically similar to the great white shark, such as C. megalodon.[2][33] Using this model, the upper anterior tooth (with maximum height of 168 millimetres (6.6 in)) possessed by Gottfried and colleagues corresponded to a total length of 15.1 metres (50 ft).[33] In 2010, shark researchers Catalina Pimiento, Dana J. Ehret, Bruce J. MacFadden and Gordon Hubbell estimated the total length of C. megalodon on the basis of Shimada's method. Among the specimens found in the Gatun Formation of Panama, specimen number 237956 yielded a total length of 16.8 metres (55 ft).[2] Later on, shark researchers (including Pimiento, Ehret and MacFadden) revisited Gatun Formation and recovered additional specimens, the specimen number 257579 yielded a total length of 17.9 metres (59 ft) on the basis of Shimada's method.[34]
Consensus



 Megalodon (gray and red) with the whale shark (violet), great white shark (green), and a human (black) for scale. Note: The maximum size attained by megalodon is indicated by the 20 m scale.
In the 1990s, marine biologists such as Patrick J. Schembri and Staphon Papson opined that C. megalodon may have approached a maximum of around 24 to 25 metres (79 to 82 ft) in total length,[35][36] however Gottfried and colleagues proposed that C. megalodon could likely approach a maximum of only 20.3 metres (67 ft) in total length.[3][5][37] Currently, most experts acknowledge that C.megalodon reached a total length of more than 16 metres (52 ft).[2][3][34][37]
Largest known specimens
Gordon Hubbell from Gainesville, Florida possesses an upper anterior megalodon tooth whose maximum height is 184.1 millimetres (7.25 in).[13] In addition, a megalodon jaw reconstruction contains a tooth whose maximum height is reportedly 193.67 millimetres (7.625 in).[38] This jaw reconstruction was developed by fossil hunter Vito Bertucci,[38] who was known as "Megalodon Man".[13][38]
Body mass estimates
Gottfried and colleagues introduced a method to determine the mass of the great white after studying the length–mass relationship data of 175 specimens at various growth stages and extrapolated it to estimate C. megalodon's mass. According to their model, a 15.9 metres (52 ft) long megalodon would have a mass of about 48 metric tons (53 short tons),[3][5] a 17 metres (56 ft) long megalodon would have a mass of about 59 metric tons (65 short tons),[5] and a 20.3 metres (67 ft) long megalodon would have a mass of 103 metric tons (114 short tons).[3][5]
Dentition and jaw mechanics



 Reconstruction showing the position of the replacement teeth.
A team of Japanese scientists, T. Uyeno, O. Sakamoto, and H. Sekine, discovered and excavated partial remains of a megalodon, with a nearly complete associated set of its teeth, from Saitama, Japan in 1989.[7] Another nearly complete associated megalodon dentition was excavated from Yorktown Formations of Lee Creek, North Carolina in the United States and served as the basis of a jaw reconstruction of C. megalodon at the American Museum of Natural History in New York City.[5] These associated tooth sets solved the mystery of how many teeth would be in the jaws of the megalodon in each row. As a result, highly accurate jaw reconstructions became possible. More associated megalodon dentitions were found in later years. Based on these discoveries, scientists S. Applegate and L. Espinosa published an artificial dental formula (representation of dentition of an animal with respect to types of teeth and their arrangement within the animal's jaw) for megalodon in 1996.[5][7] Most accurate modern C. megalodon jaw reconstructions are based on this dental formula.
The dental formula of C. megalodon is:
2.1.7.4
3.0.8.4
.[7]
As evident from the formula, C. megalodon had four kinds of teeth in its jaws.[7]
Anterior - A
Intermediate - I (megalodon's tooth technically appears to be an upper anterior and is termed as "A3" because it is fairly symmetrical and does not point mesially (side of the tooth toward the midline of the jaws where the left and right jaws meet), but this tooth is still designated as an intermediate tooth.[8] However, the great white shark's intermediate tooth does point mesially. This point was raised in the Carcharodon vs. Carcharocles debate regarding the megalodon and favors the case of Carcharocles proponents.)
Lateral - L
Posterior - P



 Reconstructed jaws on display at the National Aquarium in Baltimore.
Megalodon had a very robust dentition,[5] and had a total of about 276 teeth in its jaws, spanning 5 rows. Paleontologists suggest that a very large megalodon had jaws over 2 metres (7 ft) across.[13]
Bite force
In 2008, a team of scientists led by S. Wroe conducted an experiment to determine the bite force of the great white shark, using a 2.4 metres (8 ft) long specimen, and then isometrically scaling the results for its maximum confirmed size and the conservative minimum and maximum body mass of C. megalodon, placing the bite force of the latter between 108,514 N (24,400 lbf) and 182,201 N (41,000 lbf) in a posterior bite. Compared to 18,216 N (4,100 lbf) for the largest confirmed great white shark,[3] and 5,300 N (1,200 lbf) for the placoderm fish Dunkleosteus.[39]
In addition, Wroe and colleagues pointed out that sharks shake sideways while feeding, amplifying the post-cranial generated forces. Therefore the total force experienced by prey is likely higher than the estimate.[3] The extraordinary bite forces in C. megalodon must be considered in the context of its great size and of paleontological evidence suggesting that C. megalodon was an active predator of large whales.[3]
Functional parameters of teeth
Megalodon's exceptionally robust teeth are serrated,[8][13] which would have improved efficiency in slicing its prey's flesh. Paleontologist B. K. Kent suggested that these teeth are comparatively thicker for their size with much lower slenderness and bending strength ratios. Their roots are substantially larger relative to total tooth heights, and so have a greater mechanical advantage. Teeth with these traits are good cutting tools and are well suited for grasping powerful prey and would seldom crack even when slicing through bones.[40]
Skeletal anatomy



 Reconstructed megalodon skeleton on display at the Calvert Marine Museum.
Gottfried and colleagues further estimated the schematics of megalodon's entire skeleton.[5] To support the beast's dentition, its jaws would have been massive, stouter, and more strongly developed than those of the great white, which possesses a comparatively gracile dentition. The jaws would have given it a "pig-eyed" profile.[5] Its chondrocranium would have had a blockier and more robust appearance than the great white.[5] Its fins were proportional to its larger size.[5] Scrutiny of the partially preserved vertebral megalodon specimen from Belgium revealed that C. megalodon had a higher vertebral count than specimens of any known shark. Only the great white approached it.[5]
Full skeletal reconstruction
Using the above characteristics, Gottfried and colleagues reconstructed the entire skeleton of C. megalodon, which was later put on display at the Calvert Marine Museum at Solomon's Island, Maryland in the United States.[5][25][41] This reconstruction is 11.5 metres (38 ft) long and represents a young individual. The team stresses that relative and proportional changes in megalodon skeletal features are ontogenetic in nature in comparison to that of great white, as they occur in great whites while growing.[5] Fossil remains of C. megalodon confirm that it had a heavily calcified skeleton while alive.[14]
Paleoecological considerations
Range and habitat
Sharks, especially large species, are highly mobile and experience a complex life history amid wide distribution.[2] Fossil records indicate that it was cosmopolitan,[34] and commonly occurred in subtropical to temperate latitudes.[5] Prior to the formation of the Isthmus of Panama, the seas were relatively warmer.[42] This would have made it possible for the species to live in all oceans.
Megalodon had enough adaptability to inhabit a wide range of marine environments (i.e. coastal shallow waters, coastal upwelling, swampy coastal lagoons, sandy littorals and offshore deep water environments), and exhibited a transient lifestyle.[13][43] Adult megalodon were not abundant in shallow water environments[43] and mostly lurked offshore. C. megalodon may have moved between coastal and oceanic waters, particularly in different stages of its life cycle.
Prey relationships



Vertebral centrum of a whale bitten in half by a megalodon. Large bite marks (deep gashes) on the vertebral centrum are visible.
Sharks are generally opportunistic predators. However, scientists propose that C. megalodon was "arguably the most formidable carnivore ever to have existed."[3] Its great size,[3] high-speed swimming capability,[41] and powerful jaws coupled with formidable killing apparatus,[3][5] made it a super-predator with the capability to consume a broad spectrum of fauna.
Fossil evidence indicates that C. megalodon preyed upon cetaceans (i.e., dolphins),[5][27] small whales,[7] (including cetotherrids,[12] squalodontids,[43] and Odobenocetops[44]), and large whales,[45] (including sperm whales,[13][46] bowhead whales,[47] and rorquals[45][48]), pinnipeds,[12][20][49] porpoises,[13] sirenians,[43][50] and giant sea turtles.[43] Marine mammals were regular prey targets for megalodon. Many whale bones have been found with clear signs of large bite marks (deep gashes) made by teeth that match megalodon's.[5][7] Various excavations have revealed megalodon teeth lying close to the chewed remains of whales,[5][25] and sometimes in direct association with them.[10] Fossil evidence of interactions between megalodon and pinnipeds also exist.[20] In one interesting observation, a 127 millimetres (5.0 in) C. megalodon tooth was found lying very close to a bitten earbone of a sea lion.[49]



 Artistic impression of a megalodon pursuing two Eobalaenoptera whales.
C. megalodon faced a highly competitive environment.[4] However, its position at the top of the food chain,[51] likely had a profound impact on the structuring of marine communities.[4][5][52] Fossil evidence indicates a correlation between C. megalodon emergence and extensive diversification of cetaceans.[4][5] Juvenile megalodon preferred habitats where small cetaceans were abundant, and adult megalodon preferred habitats where large cetaceans were abundant. Such preferences may have developed shortly after they appeared in the Oligocene.[5] In addition, C. megalodon were contemporaneous with macro-predatory odontocetes (particularly raptorial sperm whales and squalodontids), which were also likely among the era's apex predators,[4][11] and provided competition.[11][53] In response to competition from giant macro-predatory sharks, macro-predatory odontocetes may have evolved defensive adaptations; some species became pack predators,[11][54] and some attained gigantic sizes, such as Livyatan melvillei.[4][55] By the end of the Miocene, raptorial sperm whales vanished from the fossil record and left an ecological void.[4]
Like other sharks, megalodon also would have been piscivorous.[12][41] Fossil evidence indicates that other notable species of macro-predatory sharks (e.g. great white sharks) responded to competitive pressure from C. megalodon by avoiding regions it inhabited.[5] Megalodon likely also had a tendency for cannibalism.[56]
Feeding strategies
Sharks often employ complex hunting strategies to engage large prey animals. Some paleontologists suggest that great white shark hunting strategies may offer clues as to how C. megalodon hunted its unusually large prey.[11] However, fossil evidence suggests that C. megalodon employed more effective hunting strategies against large prey than those of the great white shark.[40]
Paleontologists surveyed fossils to determine attacking patterns.[40] One particular specimen — the remains of a 9 metres (30 ft) long prehistoric baleen whale (of an unknown Miocene taxon) — provided the first opportunity to quantitatively analyze its attack behavior. The predator primarily focused on the tough bony portions (i.e. shoulders, flippers, rib cage, and upper spine) of the prey, which great white sharks generally avoid. Dr. B. Kent elaborated that C. megalodon attempted to crush the bones and damage delicate organs (i.e. heart, and lungs) harbored within the rib cage. Such an attack would have immobilized the prey, which would have died quickly from injuries to these vital organs. These findings also clarify why the ancient shark needed more robust dentition than that of great whites.[40] Furthermore, attack patterns could differ for prey of different sizes. Fossil remains of some small cetaceans (e.g. cetotheriids) suggest that they were rammed with great force from below before being killed and eaten.[11]
During the Pliocene, larger and more advanced cetaceans appeared.[57] Megalodon apparently further refined its hunting strategies to cope with these large whales. Numerous fossilized flipper bones (i.e., segments of the pectoral fins), and caudal vertebrae of large whales from the Pliocene have been found with megalodon bite marks. This paleontological evidence suggests that megalodon would immobilize a large whale by ripping apart or biting off its locomotive structures before killing and feeding on it.[3]
Nursery areas



 Collection of teeth of juvenile C. megalodon from a probable nursery area in the Gatun Formation of Panama.
Fossil evidence suggests that the preferred nursery sites of C. megalodon were warm water coastal environments, where threats were minor and food plentiful.[2] Nursery sites were identified in the Gatun Formation of Panama, the Calvert Formation of Maryland, Banco de Concepción in Canary Islands,[18] and the Bone Valley Formation of Florida. As is the case with most sharks, C. megalodon also gave birth to live young. The size of neonate megalodon teeth indicate that megalodon pups were around 2 to 4 metres (7 to 13 ft) in total length at birth.[2][5] Their dietary preferences display an ontogenetic shift.[5] Young megalodon commonly preyed on fish,[2] giant sea turtles,[43] dugongs[13] and small cetaceans; mature megalodon moved to off-shore cetacean high-use areas and consumed large cetaceans.[5]
However, an exceptional case in the fossil record suggests that juvenile megalodon may occasionally have attacked much larger balaenopterid whales. Three tooth marks apparently from a 4–7-metre (13–23 ft) long Pliocene macro-predatory shark were found on a rib from an ancestral great blue or humpback whale that showed evidence of subsequent healing.[48][58][59] Scientists suspect that this shark was a juvenile megalodon.[58][59]
Extinction
The subject of C. megalodon extinction remains under investigation.[11] Several possible causes for its decline and eventual disappearance have been proposed.
Oceanic cooling and sea level drops
The Earth has been in a long term cooling trend since the Miocene Climactic Optimum, 15–17 Ma ago.[60] This trend may have been accelerated by changes in global ocean circulation caused by the closure of the Central American Seaway[7][61] and/or other factors (see Pliocene climate), setting the stage for glaciation in the northern hemisphere.[61] Consequently, during the late Pliocene and Pleistocene, there were ice ages,[62][63] which cooled the oceans significantly.[7] Expansion of glaciation during the Pliocene tied up huge volumes of water in continental ice sheets, resulting in significant sea level drops.[42] The major reason cited is the decline in ocean temperatures at global scale during the Pliocene.[7][25][64] This cooling trend adversely impacted C. megalodon, as it preferred warmer waters,[5][64] and as a result it may have declined in abundance until its ultimate extinction during the Pleistocene.[64] Fossil evidence confirms the absence of C. megalodon in regions around the world where water temperatures had significantly declined during the Pliocene.[5] Furthermore, these oceanographic changes may have restricted many of the suitable warm water nursery sites for megalodon, hindering reproduction.[7] Nursery areas are pivotal for the survival of many shark species, in part because they protect juveniles from predation.[65]
Decline in food supply
Baleen whales attained their greatest diversity during the Miocene,[5] with over 20 recognized genera in comparison to only six extant genera.[66] Such diversity presented an ideal setting to support a gigantic macropredator such as C. megalodon.[5] However, by the end of the Miocene many species of mysticetes had gone extinct;[4] surviving species may have been faster swimmers and thus more elusive prey.[13][41] Furthermore, after the closure of the Central American Seaway, additional extinctions occurred in the marine environment,[67][68] and faunal redistribution took place; tropical great whales decreased in diversity and abundance.[69] Whale migratory patterns during the Pliocene have been reconstructed from the fossil record, suggesting that most surviving species showed a trend towards polar regions.[42] The cooling of the oceans during the Pliocene restricted the access of C. megalodon to polar regions, depriving it of its main food source, the great whales.[5][7][12][69] As a result of these developments, the food supply for megalodon in regions it inhabited during the Pliocene, primarily in low-to-mid latitudes, was no longer sufficient to sustain it worldwide.[7][45][69] C. megalodon were adapted to a specialized lifestyle, and this lifestyle was disturbed by these developments.[25] The resulting shortage of food sources in the tropics during Plio-Pleistocene times may have fueled cannibalism by megalodon. Juveniles were at increased risk from attacks by adults during times of starvation.[11]
New competition
Large raptorial delphinids (members of genus Orcinus) evolved during the Pliocene,[70] and likely filled the ecological void left by the disappearance of raptorial sperm whales at the end of the Miocene.[4] A minority view is that competition from ancestral killer whales may have contributed to the shark's decline[13][41][71] (another source suggests more generally that "competition with large odontocetes" may have been a factor[5]). Fossil records indicate that these delphinids commonly occurred at high latitudes during the Pliocene, indicating that they could cope with the increasingly prevalent cold water temperatures. They also occurred in the tropics (e.g., Orcinus sp. in South Africa).[70]
However, expert consensus suggests that factors such as a cooling trend in the oceans and a shortage of food sources during Plio-Pleistocene times played a significant role in megalodon's demise.[11][27] Paleontologist Albert Sanders suggests that C. megalodon was too large to sustain itself on the declining tropical food supply.[65] Other apex predators seem to have gained from the extinction of this formidable species.[27][64]
In fiction
C. megalodon has been portrayed in several works of fiction, including films and novels, and continues to hold its place among the most popular subjects for fiction involving sea monsters. Many of these works posit that at least a relict population of megalodon survived extinction and lurk in the vast depths of the ocean, and that individuals may manage to surface, either by human intervention or by natural means. Jim Shepard's story "Tedford and the Megalodon" is an example of this. Such beliefs are usually inspired by the discovery of a megalodon tooth by members of HMS Challenger in 1872, which some believed to be only 10,000 years old.[72]
Some works of fiction (such as Shark Attack 3: Megalodon and Steve Alten's Meg series) incorrectly depict C. megalodon as being a species over 70 million years old, and to live during the time of the dinosaurs. The writers of the movie Shark Attack 3: Megalodon depicted this assumption by including an altered copy of Great White Shark by shark researcher Richard Ellis. The copy shown in the film had several pages that do not exist in the book. The author sued the film's distributor, Lions Gate Entertainment, asking for a halt to the film's distribution along with $150,000 in damages.[73] Steve Alten's Meg: A Novel of Deep Terror is probably best known for portraying this inaccuracy with its prologue and cover artwork depicting C. megalodon killing a tyrannosaur in the sea. Megalodon also makes a star appearance in Mega Shark Versus Giant Octopus, where it is able to perform such feats as leaping tens of thousands of feet into the air from the ocean to attack aircraft.
The Animal Planet fictional documentary, Mermaids: The Body Found, included an encounter 1.6 million years ago between a pod of mermaids and a megalodon. Later, in August 2013, the Discovery Channel opened its annual Shark Week series with another docufiction Megalodon: The Monster Shark Lives,[74] a controversial[75][76] docufiction about the creature that presented alleged evidence in order to directly imply that Megalodon is still supposedly alive.[77] This program received criticism for being completely fictional, such as, for example, all of the supposed scientists depicted were all paid actors.[78] In 2014 Discovery will re-air The Monster Shark Lives, followed by a new one-hour program, "Megalodon: The New Evidence".[78]
Megalodon was depicted in The Land Before Time V: The Mysterious Island as a "swimming sharptooth" that pursues the main characters for a while.
See also

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For a topical guide to this subject, see Outline of sharks.List of prehistoric cartilaginous fish
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Footnotes
1.Jump up ^ μέγας. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project. Also, ὀδούς in Liddell and Scott. Retrieved 11 August 2013.
2.^ Jump up to: a b c d e f g h i j k l m n o p q Pimiento, Catalina; Dana J. Ehret; Bruce J. MacFadden; Gordon Hubbell (10 May 2010). "Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama". In Stepanova, Anna. PLoS ONE (Panama: PLoS.org) 5 (5): e10552. Bibcode:2010PLoSO...510552P. doi:10.1371/journal.pone.0010552. PMC 2866656. PMID 20479893. Retrieved 12 May 2010.
3.^ Jump up to: a b c d e f g h i j k l m Wroe, S.; Huber, D. R.; Lowry, M.; McHenry, C.; Moreno, K.; Clausen, P.; Ferrara, T. L.; Cunningham, E.; Dean, M. N.; Summers, A. P. (2008). "Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?". Journal of Zoology 276 (4): 336–342. doi:10.1111/j.1469-7998.2008.00494.x.
4.^ Jump up to: a b c d e f g h i Lambert, Olivier; Giovanni Bianucci, Klaas Post, Christian de Muizon, Rodolfo Salas-Gismondi, Mario Urbina and Jelle Reumer (1 July 2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature (Peru) 466 (7302): 105–108. Bibcode:2010Natur.466..105L. doi:10.1038/nature09067. PMID 20596020.
5.^ Jump up to: a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av Klimley, Peter; Ainley, David (1996). Great White Sharks: The Biology of Carcharodon carcharias. Academic Press. ISBN 0-12-415031-4.
6.Jump up ^ Haven, Kendall (1997). 100 Greatest Science Discoveries of All Time. Libraries Unlimited. pp. 25–26. ISBN 1-59158-265-2.
7.^ Jump up to: a b c d e f g h i j k l m n o p q Bruner, J. C. (Sep–Oct 1997). "The Megatooth shark, Carcharodon megalodon: Rough toothed, huge toothed". Mundo Marino Revista Internacional de Vida (non-refereed) (Marina) 5: 6–11. Retrieved 14 November 2011.
8.^ Jump up to: a b c d e f g h i j k l Nyberg K.G, Ciampaglio C.N, Wray G.A (2006). "Tracing the ancestry of the Great White Shark". Journal of Vertebrate Paleontology 26 (4): 806–814. doi:10.1671/0272-4634(2006)26[806:TTAOTG]2.0.CO;2. ISSN 0272-4634. Retrieved 25 December 2007.
9.Jump up ^ Agassiz, Louis (1833–1843). Recherches sur les poissons fossiles ... / par Louis Agassiz.. Neuchatel :Petitpierre. p. 41. Retrieved 8 September 2008.
10.^ Jump up to: a b Augilera, Orangel A.; García, Luis; Cozzuol, Mario A. (2008). "Giant-toothed white sharks and cetacean trophic interaction from the Pliocene Caribbean Paraguaná Formation". Paläontologische Zeitschrift (Springer Berlin) 82 (2): 204–208. doi:10.1007/BF02988410.
11.^ Jump up to: a b c d e f g h i j Narrated by: Robert Leigh (2009-04-27). "Monster Shark". Prehistoric Predators. National Geographic.
12.^ Jump up to: a b c d e f Roesch, Ben (1998). "The Cryptozoology Review: A Critical Evaluation of the Supposed Contemporary Existence of Carcharocles megalodon".
13.^ Jump up to: a b c d e f g h i j k l m n o p q r s t u Renz, Mark (2002). Megalodon: Hunting the Hunter. PaleoPress. ISBN 0-9719477-0-8.
14.^ Jump up to: a b Bendix-Almgreen, Svend Erik (15 November 1983). "Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoi'n". Bulletin of the Geological Society of Denmark (Copenhagen: Geologisk Museum) 32: 1–32. Retrieved March 2010.
15.Jump up ^ Nieves-Rivera, Angel M.; Ruizyantin, Maria ; Gottfried, Michael D. (2003). "New Record of the Lamnid Shark Carcharodon megalodon from the Middle Miocene of Puerto Rico". Caribbean Journal of Science 39: 223–227.
16.Jump up ^ Iturralde-Vinent, M.; Hubbell, G.; Rojas, R. (1996). "Catalogue of Cuban fossil Elasmobranchii (Paleocene to Pliocene) and paleogeographic implications of their Lower to Middle Miocene occurrence". Boletín de la Sociedad Jamaicana de Geología (Cuba) 31: 7–21. Retrieved 10 May 2010.
17.Jump up ^ Donovan, Stephen; Gavin, Gunter (2001). Fossil sharks from Jamaica 28. Bulletin of the Mizunami Fossil Museum. pp. 211–215.
18.^ Jump up to: a b Identifican en Canarias fósiles de 'megalodón', el tiburón más grande que ha existido
19.Jump up ^ Fitzgerald, Erich (2004). "A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia". Memoirs of Museum Victoria (Australia: Museum Victoria) 61 (2): 183–208. ISSN 1447-2554. Retrieved March 2010.
20.^ Jump up to: a b c Portell, Roger; Hubell, Gordon; Donovan, Stephen; Green, Jeremy; Harper, David; Pickerill, Ron (2008). Miocene sharks in the Kendeace and Grand Bay formations of Carriacou, The Grenadines, Lesser Antilles 44 (3). Caribbean Journal of Science. pp. 279–286.
21.Jump up ^ Hideo, Habe; Mastatoshi, Goto; Naotomo, Kaneko (22 March 2004). "Age of Carcharocles megalodon (Lamniformes: Otodontidae) : A review of the stratigraphic records". The Palaeontological Society of Japan (PSJ) (Japan) 75 (75): 7–15. ISSN 0022-9202.
22.^ Jump up to: a b c d e f g Gottfried M.D., Fordyce R.E. (2001). "An associated specimen of Carcharodon angustidens (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on Carcharodon interrelationships". Journal of Vertebrate Paleontology 21 (4): 730–739. doi:10.1671/0272-4634(2001)021[0730:AASOCA]2.0.CO;2. ISSN 0272-4634.
23.Jump up ^ Brown, Robin (2008). Florida's Fossils. Pineapple Press. ISBN 978-1-56164-409-4.
24.^ Jump up to: a b c d e Ehret D. J., Hubbell G., Macfadden B. J. (2009). "Exceptional preservation of the white shark Carcharodon from the early Pliocene of Peru" (PDF). Journal of Vertebrate Paleontology 29 (1): 1–13. doi:10.1671/039.029.0113.
25.^ Jump up to: a b c d e f g Andres, Lutz (2002). "C. megalodon — Megatooth Shark, Carcharodon versus Carcharocles". Retrieved 16 January 2008.
26.Jump up ^ Siverson, Mikael; Johan Lindgren, Michael G. Newbrey, Peter Cederström and Todd D. Cook (2013). "Late Cretaceous (Cenomanian-Campanian) mid-palaeolatitude sharks of Cretalamna appendiculata type" (PDF). Acta Palaeontologica Polonica: 2. doi:10.4202/app.2012.0137.
27.^ Jump up to: a b c d e Diedrich, C. G. (November 2013). "Evolution of white and megatooth sharks, and evidence for early predation on seals, sirenians, and whales". Natural Science (Czech Republic) 5 (11): 1203–1218. doi:10.4236/ns.2013.511148. Retrieved 22 November 2013.
28.Jump up ^ Dell-Amore, Christine (2009). "Most Complete Great White Fossil Yet". Retrieved 16 March 2009.
29.Jump up ^ Godfrey, Stephen (11 November 2006). "The Geology and Paleontology of Calvert Cliffs" (PDF). Paleontology Topics. The Ecphora Miscellaneous Publications. Retrieved 2 November 2009.
30.^ Jump up to: a b c d e f g Helfman, Gene; Collette, Bruce; Facey, Douglas (1997). The diversity of fishes. Wiley Blackwell. ISBN 978-0-86542-256-8.
31.^ Jump up to: a b c Randall, John (July 1973). "Size of the Great White Shark (Carcharodon)". Science Magazine 181 (4095): 169–170. Bibcode:1973Sci...181..169R. doi:10.1126/science.181.4095.169.
32.Jump up ^ Kowinsky, Jayson (2002). "The Size of Megalodons". Retrieved 12 January 2008.
33.^ Jump up to: a b c d e Shimada, Kenshu (5 November 2002). "The relationship between the tooth size and total body length in the white shark, Carcharodon carcharias (Lamniformes: Lamnidae)". Journal of Fossil Research (Japan) 35 (2): 28–33. ISSN 0387-1924. Retrieved 29 April 2011.
34.^ Jump up to: a b c Pimiento, Catalina; Gerardo González-Barba; Dana J. Ehret; Austin J. W. Hendy; Bruce J. MacFadden; Carlos Jaramillo (2013). "Sharks and Rays (Chondrichthyes, Elasmobranchii) from the Late Miocene Gatun Formation of Panama" (PDF). Journal of Paleontology 87 (5): 755–774. doi:10.1666/12-117.
35.Jump up ^ Schembri, Patrick (1994). "MALTA'S NATURAL HERITAGE". Natural Heritage. in (MALTA: University of MALTA): 105–124. Retrieved March 2010.
36.Jump up ^ Papson, Stephen (1992). "Copyright: Cross the Fin Line of Terror". Journal of American Culture 15 (4): 67–81. doi:10.1111/j.1542-734X.1992.1504_67.x
37.^ Jump up to: a b Compagno, Leonard J. V. (2002). SHARKS OF THE WORLD: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food & Agriculture Organization of the United Nations. p. 97. ISBN 92-5-104543-7.
38.^ Jump up to: a b c Herskowitz, David; Peter Wiggins (21 December 2010). "Huge Shark Jaw" (PDF). Natural History. Heritage Auctions. Retrieved 30 April 2011.
39.Jump up ^ Anderson, Philip; Westneat, Mark (February 2007). "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator". Royal Society 3 (1): 77–80. doi:10.1098/rsbl.2006.0569.
40.^ Jump up to: a b c d Riordon, James (June 1999). "Hell's teeth". NewScientist Magazine (2190): 32.
41.^ Jump up to: a b c d e Arnold, Caroline (2000). Giant Shark: Megalodon, Prehistoric Super Predator. Houghton Mifflin. pp. 18–19, 30. ISBN 978-0-395-91419-9.
42.^ Jump up to: a b c Gillette, Lynett. "Winds of Change". San Diego Natural History Museum. Archived from the original on 7 February 2009. Retrieved 4 April 2012.
43.^ Jump up to: a b c d e f Aguilera O., Augilera E. R. D. (2004). "Giant-toothed White Sharks and Wide-toothed Mako (Lamnidae) from the Venezuela Neogene: Their Role in the Caribbean, Shallow-water Fish Assemblage". Caribbean Journal of Science 40 (3): 362–368.
44.Jump up ^ "Fact File: Odobenocetops". BBC. Retrieved 21 March 2008.
45.^ Jump up to: a b c Morgan, Gary S. (August 1994). "Whither the giant white shark?". Paleontology Topics (Paleontological Research Institution).
46.Jump up ^ "MEGALODON". Fossil Farm Museum Of The Fingerlakes. Retrieved 1 July 2010.
47.Jump up ^ deGruy, Michael (2006). Perfect Shark (TV-Series). BBC.
48.^ Jump up to: a b Godfrey, Stephen (April 2004). "The Ecphora: Fascinating Fossil Finds" (PDF). Paleontology Topics. Calvert Marine Museum. Retrieved 21 February 2010.
49.^ Jump up to: a b Kehe, Andy (27 June 1998). "Bone Apetite". Archived from the original on 18 May 2008. Retrieved 19 August 2012.
50.Jump up ^ Godfrey, Stephen (March 2007). "The Ecphora: Shark-Bitten Sea Cow Rib" (PDF). Paleontology Topics. Calvert Marine Museum. Retrieved 27 March 2010.
51.Jump up ^ Compagno, Leonard J. V. (May 1989). "Copyright: Alternative life-history styles of cartilaginous fishes in time and space". Environmental Biology of Fishes 28: 33–75. doi:10.1007/BF00751027.
52.Jump up ^ Ferretti, Francesco; Boris Worm; Gregory L. Britten; Michael R. Heithaus; Heike K. Lotze1 (August 2010). "Patterns and ecosystem consequences of shark declines in the ocean". Ecology Letters (Blackwell Publishing Ltd) 13 (8): 1055–1071. doi:10.1111/j.1461-0248.2010.01489.x. PMID 20528897. Retrieved 19 February 2011.
53.Jump up ^ "New Leviathan Whale Was Prehistoric "Jaws"?". National Geographic Daily News (Peru: National Geographic). 30 June 2010.
54.Jump up ^ Bianucci, Giovanni; Walter, Landini (8 September 2006). "Killer sperm whale: a new basal physeteroid (Mammalia, Cetacea) from the Late Miocene of Italy". Zoological Journal of the Linnean Society 148 (1): 103–131. doi:10.1111/j.1096-3642.2006.00228.x.
55.Jump up ^ "Ancient monster whale more fearsome than Moby Dick". NewScientist. Retrieved 30 June 2010.
56.Jump up ^ Tanke, Darren; Currie, Philip (December 1998). Head-Biting Behaviour in Theropod Dinosaurs: Paleopathological Evidence. Gaia 15. p. 168. ISSN 0871-5424.
57.Jump up ^ Deméré, Thomas A.; Berta, Annalisa; McGowen, Michael R. (2005). "The taxonomic and evolutionary history of fossil and modern balaenopteroid mysticetes". Journal of Mammalian Evolution 12 (1/2): 99–143. doi:10.1007/s10914-005-6944-3.
58.^ Jump up to: a b "Details of ancient shark attack preserved in fossil whale bone". Smithsonian. Retrieved 12 November 2011.
59.^ Jump up to: a b Kallal, R. J.; Godfrey, S. J.; Ortner, D. J. (27 August 2010). "Bone Reactions on a Pliocene Cetacean Rib Indicate Short-Term Survival of Predation Event". International Journal of Osteoarchaeology 22 (3): 253. doi:10.1002/oa.1199. Retrieved 13 November 2011.
60.Jump up ^ Böhme, M. (14 May 2003). "The Miocene Climatic Optimum: evidence from ectothermic vertebrates of Central Europe". Palaeogeography, Palaeoclimatology, Palaeoecology 195 (3–4): 389–401. doi:10.1016/S0031-0182(03)00367-5. Retrieved 16 June 2012.
61.^ Jump up to: a b "How the Isthmus of Panama Put Ice in the Arctic". 22 March 2004. Retrieved 20 December 2008.
62.Jump up ^ "Pliocene epoch". Retrieved 16 January 2008.
63.Jump up ^ "Pleistocene epoch". Retrieved 16 January 2008.
64.^ Jump up to: a b c d Antunes, Miguel Telles; Ausenda Cáceres Balbino (March 2010). "The Great White Shark Carcharodon carcharias (Linne, 1758) in the Pliocene of Portugal and its Early Distribution in Eastern Atlantic". Revista Española de Paleontología (Portugal) 25 (1): 1–6. ISSN 0213-6937. Retrieved 19 February 2011.
65.^ Jump up to: a b Reilly, Michael (29 September 2009). "Prehistoric Shark Nursery Spawned Giants". USA: Discovery News. Archived from the original on 2012-03-10. Retrieved 23 November 2013.
66.Jump up ^ Dooly A.C, Nicholas C.F, Luo Z.X (2006). "The earliest known member of the rorqual—gray whale clade (Mammalia, Cetacea)". Journal of Vertebrate Paleontology 24 (2): 453–463. doi:10.1671/2401. JSTOR 4524731.
67.Jump up ^ Domning, Daryl P. (1 February 2001). "Sirenians, seagrasses, and Cenozoic ecological change in the Caribbean". Palaeogeography, Palaeoclimatology, Palaeoecology (USA: Elsevier) 166 (1–2): 27–50. doi:10.1016/S0031-0182(00)00200-5. Retrieved 26 April 2011.
68.Jump up ^ Fordyce, R. Ewan; Patrick G. Quilty; James Daniels (2002). "Australodelphis mirus, a bizarre new toothless ziphiid-like fossil dolphin (Cetacea: Delphinidae) from the Pliocene of Vestfold Hills, East Antarctica". Antarctic Science (Cambridge University Press) 14 (1): 37–54. doi:10.1017/S0954102002000561.
69.^ Jump up to: a b c Allmon, Warren D.; Steven D. Emslie; Douglas S. Jones; Gary S. Morgan (2006). "Late Neogene Oceanographic Change along Florida's West Coast: Evidence and Mechanisms". The Journal of Geology (USA: The University of Chicago) 104 (2): 143–162. Bibcode:1996JG....104..143A. doi:10.1086/629811.
70.^ Jump up to: a b Heyning, John; Dahlheim, Marilyn (15 January 1988). "Mammalian Species: Orcinus Orca". The American Society of Mammalogists 304: 1–9.
71.Jump up ^ Turner, Pamela S. (Oct–Nov 2004). "Showdown at Sea: What happens when great white sharks go fin-to-fin with killer whales?". National Wildlife (National Wildlife Federation) 42 (6). Retrieved 21 August 2012.
72.Jump up ^ "Mega Jaws". MonsterQuest. Season 3. Episode 7. 18 March 2009.
73.Jump up ^ Boniello, Kathianne (12 July 2009). "Shark Film has Writer Biting Mad". New York Post.
74.Jump up ^ "Shark Week 'Megalodon: The Monster Shark Lives' Tries To Prove Existence Of Prehistoric Shark (VIDEO)". Huff Post Green. 5 August 2013. Retrieved 11 August 2013.
75.Jump up ^ Wilcox, Christie (5 August 2013). "Shark Week Jumps The Shark: An Open Letter To Discovery Communications". Discover Magazine. Retrieved 11 August 2013.
76.Jump up ^ Wilcox, Christie (9 August 2013). "Discovery’s Megalodon Defense? ‘We Don’t Know,’ Or ‘We Don’t Care’". Discover Magazine. Retrieved 11 August 2013.
77.Jump up ^ Juzwiak, Rich (5 August 2013). "Shark Week Opens With Fake Megalodon Documentary". gawker.com. Retrieved 11 August 2013.
78.^ Jump up to: a b "Shark Week's dark side: After fake documentary controversy, Discovery doubles down on its lies". OregonLive.com. Retrieved 2014-08-06.
References
Bretton W. Kent (1994). Fossil Sharks of the Chesapeake Bay Region. Egan Rees & Boyer, Inc. 146 pages. ISBN 1-881620-01-8
Dickson, K. A., Graham, J. B. (2004). "Evolution and consequences of endothermy in fishes". Physiological and Biochemical Zoology 77 (6): 998–1018. doi:10.1086/423743. PMID 15674772.
External links
 Wikimedia Commons has media related to Carcharodon megalodon.
 Wikispecies has information related to: Megalodon
Extinct Megalodon, the largest shark ever, may have grown too big
Carcharocles: Extinct Megatoothed shark
Dykens, M.; Gillette, L. "SDNHM Fossil Field Guide: Carcharodon megalodon, Giant "Mega-Tooth" Shark". Archived from the original on 13 June 2011. Retrieved 29 April 2012.
Jurassic Shark
Megalodon article on prehistoric-wildlife.com
Paleontological videos
NOTE: Flash Player is required to view the content below.
Megalodon Giant Shark – National Geographic (full documentary)
Video Gallery containing video clips featuring megalodon from Discovery Channel
Paleontologist Mark Renz shows a huge megalodon tooth (one of the largest ever discovered) on YouTube
A video clip on YouTube depicting aggressive interspecific interactions between megalodon and a pod of killer odontoceti (Brygmophyseter shigensis) from History Channel
Animated size comparison of megalodon with great white shark, human, and school bus from North Carolina Museum of Natural Sciences on YouTube.
Prehistoric Washington DC: Mega Shark from Discovery Channel (depicts megalodon's prey attacking strategies)
Shark Week Special on megalodon with Pat McCarthy and John Babiarz on YouTube with comments on its extinction.
Megalodon fossil teeth show evidence of 10-million-year-old shark nursery on YouTube
Expert view: information about megalodon on YouTube (featuring expert Dana Ehret)
Lamniform sharks: 110 million years of ocean supremacy on YouTube (featuring expert Mikael Siverson)
The Rise and Fall of the Neogene Giant Sharks on YouTube (featuring expert Bretton Kent)
Clash of the Americas on YouTube (Megalodon's extinction discussed)
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