Early Miocene-Late Pliocene, ~23–2.6 Ma
|Model of megalodon jaws at the American Museum of Natural History|
Megalodon (Carcharocles megalodon), meaning "big tooth" from Ancient Greek: μέγας (megas) "big, mighty" and ὀδoύς (odoús) "tooth", is an extinct species of shark that lived approximately 23 to 2.6 million years ago (mya), during the Early Miocene to the end of the Pliocene. In the past, the two major interpretations were Carcharodon megalodon (under the family Lamnidae) or Carcharocles megalodon (under the family Otodontidae). However, consensus has been reached that the latter view is correct and that megalodon is of the family Otodontidae deriving from sharks of the genus Otodus, and thus should be placed under the genus Carcharocles. The shark has made appearances in several works of fiction such as the Discovery Channel's Megalodon: The Monster Shark Lives.
Scientists suggest that megalodon looked like a stockier version of the great white shark (Carcharodon carcharias). Regarded as one of the largest and most powerful predators in vertebrate history, fossil remains of megalodon suggest that this giant shark reached a length of 18 meters (59 ft), though there are many other competing figures; for example, 24 to 25 meters (79 to 82 ft). Their large jaws could exert a bite force of up to 110,000 to 180,000 newtons (25,000 to 40,000 lbf). Their teeth were thick and robust, built for grabbing prey and breaking bone.
Megalodon probably had a profound impact on the structure of marine communities. The fossil record indicates that it had a cosmopolitan distribution. It probably targeted large prey, such as whales, seals, and giant turtles. Juveniles inhabited warm coastal waters where they would feed on fish and small whales. Unlike the great white which attacks prey from the soft underside, megalodon probably used its strong jaws to break through the chest cavity and puncture the heart and lungs of its prey.
The animal faced competition from whale-eating cetaceans, such as Livyatan and killer whales (Orcinus orca), which likely contributed to its extinction. As it preferred warmer waters, it is thought that oceanic cooling associated with the onset of the ice ages, coupled with the lowering of sea levels and resulting loss of suitable nursing areas, may have also contributed to its decline. A reduction in the diversity of baleen whales and a shift in their distribution toward polar regions may have reduced megalodon's primary food source. The extinction of the shark appeared to affect other animals; for example, the size of baleen whales increased significantly after the shark had disappeared.
- 1 Taxonomy
- 2 Anatomy
- 3 Paleobiology
- 4 Extinction
- 5 In fiction
- 6 See also
- 7 References
- 8 Further reading
- 9 External links
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. He described his findings in the book The Head of a Shark Dissected, which also contained an illustration of a megalodon tooth.
Swiss naturalist Louis Agassiz gave the shark its initial scientific name, Carcharodon megalodon, in 1835, in his research work Recherches sur les poissons fossiles. The specific name megalodon translates to "big tooth", from Ancient Greek: μέγας (megas) "big, mighty" and ὀδoύς (odoús), "tooth" Megalodon teeth are morphologically similar to the teeth of the great white shark (Carcharodon carcharias), and on the basis of this observation, Agassiz assigned megalodon to the genus Carcharodon. The shark is also often informally dubbed the "giant white shark," the "megatooth shark," the "big tooth shark," or "Meg".:4
While the earliest megalodon remains were reported from the Late Oligocene dated to around 28 million years ago (mya), competing figures still exist as to when it evolved, such as 16 mya and 23 mya. It is believed that megalodon became extinct around the end of the Pliocene, probably about 2.6 mya; reported Pleistocene megalodon teeth are considered to be unreliable claims.
The most common fossils of megalodon are its teeth. Diagnostic characteristics include a triangular shape, robust structure, large size, fine serrations, and a visible V-shaped neck (where the root meets the crown).:55 Megalodon teeth can measure over 180 millimeters (7 in) in slant height (diagonal length) and are the largest of any known shark species.:33
Some fossil vertebrae have been found. The most notable example is a partially preserved vertebral column of a single specimen, excavated in the Antwerp Basin, Belgium in 1926. It comprises 150 vertebral centra, with the centra ranging from 55 millimeters (2.2 in) to 155 millimeters (6 in) in diameter. However, the shark's vertebrae may have gotten much bigger.:63–64 Another partially preserved vertebral column of a megalodon was excavated from Gram Formation in Denmark in 1983. This specimen comprises 20 vertebral centra, with the centra ranging from 100 millimeters (4 in) to 230 millimeters (9 in) in diameter.
|Relationship between megalodon and the great white shark (Carcharodon carcharias)|
The great white shark was previously considered to be a close relative to megalodon, and the two were placed in the same genus, due to dental similarity, but most authors currently believe that this is due to convergent evolution. In this model, the great white shark is more closely related to the shark Isurus hastalis than to megalodon, as evidenced by more similar dentition in those two sharks; megalodon teeth have much finer serrations than great white shark teeth. However, proponents of the former model, wherein megalodon and the great white shark are more closely related, argue that the differences between their dentition are minute and obscure.:23–25 In this model, the great white shark is more closely related to the mako shark, with a common ancestor around 4 mya. However, some great white shark fossils are about 16 million years old and predate the transitional Pliocene fossils.
Megalodon was previously considered to be a member of the family Lamnidae, but it is now considered to be a member of the family Otodontidae, genus Carcharocles. The genus Carcharocles currently contains four species: C. auriculatus, C. angustidens, C. chubutensis, and C. megalodon.:30–31 The genus was proposed by D. S. Jordan and H. Hannibal in 1923 to classify the shark C. auriculatus into. Later on in the 1980s, megalodon was assigned to Carcharocles.:30
Before this, however, in 1960, the genus Procarcharodon was erected and included those four sharks, and was considered separate from the great white shark. It is now considered a junior synonym of Carcharocles.:30 The genus Palaeocarcharodon was erected alongside Procarcharodon to represent the beginning of the lineage, and, in the model wherein megalodon and the great white shark are closely related, their last common ancestor. However, it is believed to be an evolutionary dead-end and unrelated to the Carcharocles sharks by authors who reject that model.:70
Another model of the evolution of this genus is that the direct ancestor of the Carcharocles is the shark Otodus obliquus, which lived during the Paleocene and Eocene epochs. In this model, O. obliquus evolved into O. aksuaticus, which evolved into C. auriculatus, and then into C. angustidens, and then into C. chubutensis, and then finally into C. megalodon. The evolution of this lineage is characterized by the increase of serrations, the widening of the crown, the development of a more triangular shape, and the disappearance of the lateral cusps.:28–31 The genus Otodus is ultimately derived from Cretolamna, a shark from the Cretaceous period.
Another model of the evolution of Carcharocles is that the three other species are actually a single species of shark that gradually changed over time between the Paleocene and the Pliocene, making it a chronospecies.:17 Some authors suggest that C. auriculatus, C. angustidens, and C. chubutensis should be classified as a single species in the genus Otodus, leaving C. megalodon the sole member of Carcharocles.
The genus Carcharocles may be invalid, and the shark may actually belong in the genus Otodus, making it Otodus megalodon. A 1974 study on Paleogene sharks erected the subgenus Megaselachus, classifying the shark as Otodus (Megaselachus) megalodon, along with O. (M.) chubutensis. A 2006 review of Chondrichthyes elevated Megaselachus to genus, and classified the sharks as Megaselachus megalodon and M. chubutensis. The discovery of fossils assigned to the genus Megalolamna in 2016 led to a re-evaluation of Otodus, which concluded that it is a paraphyly. The inclusion of the Carcharocles sharks in Otodus would make it monophyletic, with the sister clade being Megalolamna.
One idea on how megalodon appeared was that it was a robust-looking shark, and may have had a similar build to the great white shark. The jaws may have been blunter and wider than the great white, and it may have had a pig-eyed appearance, in that it had deep-set and small eyes. The fins would have also been similar in shape, though thicker due to its size.:64–65
Another idea is that megalodon bore a similarity to the whale shark (Rhincodon typus) or the basking shark (Cetorhinus maximus). The tail fin would have been crescent-shaped, the anal fin and second dorsal fin would have been small, and there would have been a caudal keel present on either side of the tail fin (on the caudal peduncle). This build is common in other large aquatic animals, such as whales, tuna, and other sharks, in order to reduce drag while swimming. The head shape, however, can vary between species as most of the drag-reducing adaptations are toward the tail end of the animal.:35–36
Since Carcharocles is derived from Otodus, and the two had teeth that bear a close similarity to those of the sand tiger shark (Carcharias taurus), megalodon may have had a build more similar to the sand tiger shark than to other sharks. However, since sand tiger sharks are axial swimmers that flex their body for propulsion, and use drag to displace water, they are required to move around three or four times their own weight in water on each tail stroke. A large sand tiger shark would require large fins to propel itself, however this in itself would create more drag and offset efficiency, so it is unlikely that they had similar body shapes given how large megalodon was.:35–36
Due to fragmentary remains, there have been many contradictory size estimates for megalodon, as they can only be drawn from fossil teeth and vertebra.:87 Due to the lack of well-preserved fossil megalodon skeletons, the great white shark is the basis of its reconstruction and size estimation,:57 as it is regarded as the best analogue to megalodon. Various size estimates exist for megalodon; one possible maximum size estimate is 18 metres (59 ft), with the average size being 10.5 metres (34 ft); however other estimates calculate that the maximum length attained was 24 to 25 meters (79 to 82 ft). It is possible that different populations of megalodon around the globe had different body sizes and behaviors due to different ecological pressures. If it did attain a size of over 16 metres (52 ft), it would have been the largest fish that has ever lived, surpassing the Jurassic fish Leedsicthys.
Mature male megalodons may have had a body mass of 12.6 to 33.9 metric tons (13.9 to 37.4 short tons), and mature females may have been 27.4 to 59.4 metric tons (30.2 to 65.5 short tons), given that males could range in length from 10.5 to 14.3 metres (34 to 47 ft) and females 13.3 to 17 metres (44 to 56 ft).:61 A 2015 study linking shark size and typical swimming speed estimated that megalodon would have typically swam at 18 kilometres per hour (11 mph), given that its body mass was typically 48 metric tons (53 short tons), which is consistent with other aquatic creatures of its size, such as the fin whale which typically cruises at speeds of 14.5 to 21.5 kilometres per hour (9.0 to 13.4 mph).
Its large size may have been due to climactic factors and the abundance of large prey items, and it may have also been influenced by the evolution of regional endothermy (mesothermy) which would have increased its metabolism. However, since the Otodontidae sharks are considered to have been ectotherms, and megalodon was a close relative to them, megalodon may have also been ectothermic. Contrary to this, the largest contemporary ectothermic sharks, such as the whale shark, are filter feeders, implying some metabolic constraints with a predatory lifestyle.
The first attempt to reconstruct the jaw of megalodon was made by Bashford Dean in 1909, displayed at the American Museum of Natural History. From the dimensions of this jaw reconstruction, it was hypothesized that megalodon could have approached 30 meters (98 ft) in length. However, Dean had overestimated the size of the cartilage on both jaws, causing it to be too tall.
John E. Randall, an ichthyologist, used the enamel height (the vertical distance of the blade from the base of the enamel portion of the tooth to its tip) to measure the length of the shark, yielding a maximum length of about 13 meters (43 ft). However, tooth enamel height does not necessarily increase in proportion to the animal's total length.:99
Shark researchers Michael D. Gottfried, Leonard Compagno, and S. Curtis Bowman proposed a linear relationship between a shark's total length and the height of the largest upper anterior tooth. The proposed relationship is: total length in meters = − (0.096) × [UA maximum height (mm)]-(0.22).:60 They had estimated the average height, based on the slant height of the largest tooth discovered, for large female megalodon to be 15.6 meters (51 ft), though larger teeth may exist.:55–60
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 centimeter (0.39 in) of root width, there are approximately 1.4 meters (4.6 ft) of shark length. 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 tool for estimating jaw perimeter. The largest tooth in Jeremiah's possession had a root width of about 12 centimeters (4.7 in), which yielded 16.5 meters (54 ft) in total length.:88
In 2002, paleontologist Kenshu Shimada of DePaul University proposed a linear relationship between tooth crown height and total length after conducting anatomical analysis of several specimens, allowing any sized tooth to be used. Shimada pointed out that the previously proposed methods were based on a weaker evaluation of the dental homology between megalodon and the great white shark, and that the growth rate between the crown and root is not isometric, which he considered in his model. Using this model, the upper anterior tooth possessed by Gottfried and colleagues corresponded to a total length of 15 meters (49 ft). Among the specimens found in the Gatun Formation of Panama, other shark researchers used this method and calculated a maximum height of 16.8 meters (55 ft) for a specimen, and for another a total length of 17.9 meters (59 ft). However this result appears to be an error within the matrix and the average position for this individual is actually 19.6 meters (64 ft) 
Largest known specimens
Gordon Hubbell from Gainesville, Florida, possesses an upper anterior megalodon tooth whose maximum height is 184.1 millimeters (7.25 in).:87 In addition, a 2.7-by-3.4-meter (9 by 11 ft) megalodon jaw reconstruction contains a tooth whose maximum height is reportedly 193.67 millimeters (7.625 in). This jaw reconstruction was developed by fossil hunter Vito Bertucci, who was known as "Megalodon Man".
Teeth and bite force
In 1989, a nearly complete set of megalodon teeth was discovered in Saitama, Japan. Another nearly complete associated megalodon dentition was excavated from the Yorktown Formations in the United States, and served as the basis of a jaw reconstruction of megalodon at the National Museum of Natural History (USNM), which is part of the Smithsonian Institution. Based on these discoveries, an artificial dental formula was put together for megalodon in 1996.:55
The dental formula of megalodon is: 188.8.131.52. As evident from the formula, megalodon had four kinds of teeth in its jaws: anterior, intermediate, lateral, and posterior. Megalodon's intermediate 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 intermediate. Megalodon had a very robust dentition,:20–21 and had over 250 teeth in its jaws, spanning 5 rows.:iv It is possible that large megalodon individuals had jaws spanning roughly 3.0 meters (10 ft) across.:129 The teeth were also serrated, which would have improved efficiency in cutting through flesh or bone.:1 The shark may have been able to open its mouth to a 75° angle, though a reconstruction at USNM approximates a 100° angle.:63
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 2.5-meter (8 ft) long specimen, and then isometrically scaling the results for its maximum confirmed size and the conservative minimum and maximum body mass of megalodon. They placed the bite force of the latter between 108,514 and 182,201 N (24,390 and 40,960 lbf) in a posterior bite, compared to the 18,216 N (4,095 lbf) bite force for the largest confirmed great white shark, and 5,400 N (1,210 lbf) for the placoderm fish Dunkleosteus. In addition, Wroe and colleagues pointed out that sharks shake sideways while feeding, amplifying the force generated, which would probably have caused the total force experienced by prey to be higher than the estimate.
Megalodon is represented in the fossil record by teeth and vertebral centra.:57 As with all sharks, the skeleton of megalodon was formed of cartilage rather than bone; this means that most fossil specimens are poorly preserved. To support its large dentition, the jaws of megalodon would have been more 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. Its chondrocranium would have had a blockier and more robust appearance than that of the great white. Its fins were proportional to its larger size. Scrutiny of the partially preserved vertebral megalodon specimen from Belgium revealed that it had a higher vertebral count than specimens of any known shark, possibly over 200 centra. Only the great white approached it.:64–65
Gottfried and colleagues reconstructed the entire skeleton of megalodon, which was later put on display at the Calvert Marine Museum in the United States and the Iziko South African Museum.:56 This reconstruction is 11.3 meters (37 ft) long and represents a mature male, though relative and proportional changes in the skeletal features of megalodon are ontogenetic in nature, in comparison to those of the great white, as they also occur in great white sharks while growing.:61
Range and habitat
Megalodon had a cosmopolitan distribution; its fossils have been excavated from many parts of the world, including Europe, Africa, the Americas, and Australia.:67 It most commonly occurred in subtropical to temperate latitudes.:78 It has been found at latitudes up to 55° N; its inferred tolerated temperature range is 1–24 °C (34–75 °F). It arguably had the capacity to endure such low temperatures due to mesothermy, the physiological capability of large sharks to conserve metabolic heat by maintaining a higher body temperature than the surrounding water.
Megalodon inhabited a wide range of marine environments (i.e., shallow coastal waters, areas of coastal upwelling, swampy coastal lagoons, sandy littorals, and offshore deep water environments), and exhibited a transient lifestyle. Adult megalodon were not abundant in shallow water environments, and mostly inhabited offshore areas. Megalodon may have moved between coastal and oceanic waters, particularly in different stages of its life cycle.:33 However, megalodon teeth have been excavated from regions far away from continental lands, such as the Marianas Trench in the Pacific Ocean.:iv
Fossil remains show a trend for specimens to be larger on average in the southern hemisphere than in the northern, with mean lengths of 11.6 and 9.6 meters (38 and 31 ft), respectively; and in the Pacific more so than the Atlantic, with mean lengths of 10.9 and 9.5 meters (36 and 31 ft) respectively. They do not, however, suggest any trend of changing body size with absolute latitude, or of change in size over time (although the megatooth lineage in general is thought to display a trend of increasing size over time). The overall modal length has been estimated at 10.5 meters (34 ft), with the length distribution skewed towards larger individuals, suggesting an ecological or competitive advantage for larger body size.
Locations of fossils
Megalodon had a global distribution and fossils of the shark have been found in many places around the world, bordering all oceans of the Neogene.
Sharks generally are opportunistic feeders, but scientists propose that megalodon was largely a formidable predator. Its great size, high-speed swimming capability, and powerful jaws, coupled with a formidable feeding apparatus, made it an apex predator capable of consuming a broad spectrum of animals.:71–75 A study focusing on calcium isotopes of extinct and extant elasmobranch sharks and rays revealed that megalodon fed at a higher trophic level than the contemporaneous great white shark.
Fossil evidence indicates that megalodon preyed upon many cetacean species, such as dolphins, small whales, cetotheres, squalodontids, sperm whales, bowhead whales, and rorquals. In addition to this, they also targeted seals, sirenians, and large sea turtles. Being an opportunist, it would have also gone after smaller fish and other sharks given the opportunity. Like other sharks, megalodon also would have been piscivorous. Many whale bones have been found with deep gashes most likely made by their teeth.:75 Various excavations have revealed megalodon teeth lying close to the chewed remains of whales,:75 and sometimes in direct association with them.
The feeding ecology of megalodon appears to have varied with age and between sites, like the modern great white. It is plausible that the adult megalodon population off the coast of Peru targeted primarily cetothere whales 2.5 to 7 meters (8.2 to 23 ft) in length and other prey smaller than itself, rather than large whales in the same size class as themselves. Meanwhile, juveniles likely had a diet that consisted more of fish.
Megalodon faced a highly competitive environment. However, its position at the top of the food chain probably had a profound impact on the structuring of marine communities. Fossil evidence indicates a correlation between megalodon and the emergence and diversification of cetaceans and other marine mammals.:78 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.:74–75
Megalodon were contemporaneous with whale-eating odontocetes (particularly killer sperm whales and squalodontids), which were also probably among the era's apex predators, and provided competition. In response to competition from megalodon, whale-eating odontocetes may have evolved defensive adaptations; some species became pack predators, and some attained gigantic sizes, such as Livyatan melvillei, which grew from 13.5 to 17.5 meters (44 to 57 ft). By the Late Miocene, killer sperm whales experienced a significant decline in abundance and diversity. However, other hyper-predatory cetaceans began to emerge during the Pliocene to fill this ecological void, such as the killer whale (Orcinus orca).
Fossil evidence indicates that other notable species of sharks, such as the great white shark, responded to competitive pressure from megalodon by avoiding regions it inhabited by mainly inhabiting the cooler waters of the time. In areas where their ranges seems to overlap, such as in Pliocene Baja California, it is possible that megalodon and the great white shark occupied the area at different times of the year while following different migratory prey.:77 The shark probably also had a tendency for cannibalism, much like contemporary sharks.
Sharks often employ complex hunting strategies to engage large prey animals. Great white shark hunting strategies may be similar to how megalodon hunted its large prey. However, megalodon bite marks on whale fossils suggests that it employed different hunting strategies against large prey than the great white shark.
One particular specimen – the remains of a 9 meters (30 ft) long prehistoric baleen whale (of an unknown Miocene taxon) – provided the first opportunity to quantitatively analyze its attack behavior. Unlike great whites which target the underbelly of their prey, megalodon probably targeted the heart and lungs, with their thick teeth adapted for biting through tough bone, as indicated by bite marks inflicted to the rib cage and other tough bony areas on whale remains. They probably also targeted the flipper in order to immobilize the whale before killing it. Furthermore, attack patterns could differ for prey of different sizes. Fossil remains of some small cetaceans, for example cetotheres, suggest that they were rammed with great force from below before being killed and eaten.
During the Pliocene, larger and more advanced cetaceans appeared. 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 suggests that megalodon would immobilize a large whale by ripping apart or biting off its locomotive structures before killing and feeding on it.
Fossil evidence suggests that the preferred nursery sites of megalodon were warm-water coastal environments, where threats were minor and food plentiful. Nursery sites were identified in the Gatun Formation of Panama, the Calvert Formation of Maryland, Banco de Concepción in the Canary Islands,, and the Bone Valley Formation of Florida. Given that all extant lamniform sharks give birth to live young, this is believed to have been true of megalodon also. Neonate megalodons were around 3.5 meters (11 ft) at their smallest,:61 and the pups were vulnerable to predation by other shark species, such as the great hammerhead shark (Sphyrna mokarran) and the snaggletooth shark (Hemipristis serra). Their dietary preferences display an ontogenetic shift::65 Young megalodon commonly preyed on fish, giant sea turtles, dugongs,:129 and small cetaceans; mature megalodon moved to off-shore areas and consumed large cetaceans.:74–75
However, an exceptional case in the fossil record suggests that juvenile megalodon may have occasionally attacked much larger balaenopterid whales. Three tooth marks apparently from a 4-to-7-meter (13 to 23 ft) long Pliocene shark were found on a rib from an ancestral blue or humpback whale that showed evidence of subsequent healing, which is suspected to have been inflicted by a juvenile megalodon.
The Earth experienced a number of changes during the time period megalodon existed which affected marine life. A cooling trend starting in the Oligocene 35 mya ultimately led to glaciation at the poles. Geological events changed currents and precipitation; among these were the closure of the Circumtropical Seaway between the Americas and through the Tethys Sea, contributing to the cooling of the oceans. The stalling of the Gulf Stream prevented nutrient-rich water from reaching major marine ecosystems, which may have negatively affected its food sources. As its range did not apparently extend into colder waters, megalodon may not have been able to retain a significant amount of metabolic heat, so its range was restricted to shrinking tropical waters. Fossil evidence confirms the absence of megalodon in regions around the world where water temperatures had significantly declined during the Pliocene.:77 The largest fluctuation of sea levels in the Cenozoic era occurred in the Plio-Pleistocene due to the expansion of glaciers at the pole, which negatively impacted coastal environments, and may have contributed to its extinction along with those of several other marine megafaunal species. These oceanographic changes, in particular the sea level drops, may have restricted many of the suitable shallow warm-water nursery sites for megalodon, hindering reproduction. Nursery areas are pivotal for the survival of many shark species, in part because they protect juveniles from predation.
However, an analysis of the distribution of megalodon over time suggests that climate change did not play a major role in its extinction. Its distribution during the Miocene and Pliocene did not correlate with warming and cooling trends; while abundance and distribution declined during the Pliocene, megalodon did show a capacity to inhabit anti-tropical latitudes. It was found in locations with a mean temperature ranging from 12 to 27 °C (54 to 81 °F), with a total range of 1 to 33 °C (34 to 91 °F), indicating that the global extent of suitable habitat should not have been greatly affected by the temperature changes that occurred.
Marine mammals attained their greatest diversity during the Miocene,:71 such as with baleen whales with over 20 recognized genera in comparison to only six extant genera. Such diversity presented an ideal setting to support a super-predator such as megalodon.:75 However, by the end of the Miocene, many species of mysticetes had gone extinct; surviving species may have been faster swimmers and thus more elusive prey.:46 Furthermore, after the closure of the Central American Seaway, tropical whales decreased in diversity and abundance. The extinction of megalodon correlates with the decline of many small mysticete lineages, and it is possible that it was quite dependent on them as a food source. Additionally, a marine megafauna extinction during the Pliocene was discovered to have eliminated 36% of all large marine species including 55% of marine mammals, 35% of seabirds, 9% of sharks, and 43% of sea turtles, likely aiding in its extinction; megalodon may have been too large to sustain itself on the declining tropical food supply. The cooling of the oceans during the Pliocene might have restricted the access of megalodon to the polar regions, depriving it of its food source of large whales which had migrated there.
Competition from new superpredators, such as killer sperm whales which appeared in the Miocene, and killer whales and great white sharks in the Pliocene, may have also contributed to the decline and extinction of megalodon.:46–47 Fossil records indicate that the new whale-eating cetaceans commonly occurred at high latitudes during the Pliocene, indicating that they could cope with the increasingly prevalent cold water temperatures; but they also occurred in the tropics (e.g., Orcinus sp. in South Africa).
The extinction of megalodon set the stage for further changes in marine communities. The average body size of baleen whales increased significantly after its disappearance, although possibly due to other, climate-related, causes. Conversely however, the increase in baleen whale size may have contributed to the extinction of megalodon, as they may have preferred to go after smaller whales; bite marks on large whale species may have come from scavenging sharks. Megalodon may have simply become coextinct with smaller whale species, such as Piscobalaena nana. The extinction of megalodon had a positive impact on other apex predators of the time, such as the great white shark, in some cases spreading to regions where megalodon became absent.
Megalodon has been portrayed in several works of fiction, including films and novels, and continues to be a popular subject for fiction involving sea monsters. Three individual megalodon, two adults and one juvenile, were portrayed in BBC's 2003 TV series Sea Monsters, where it is defined as a "hazard" to the era. The History Channel's Jurassic Fight Club portrays a megalodon attacking a Brygmophyseter sperm whale in Japan. Several films depict megalodon, such as Shark Attack 3: Megalodon and the Mega Shark series (for instance Mega Shark Versus Giant Octopus and Mega Shark Versus Crocosaurus). In Justice League: Throne of Atlantis, Aquaman summons one to defeat Black Manta. Some stories, such as Jim Shepard's Tedford and the Megalodon, portray a rediscovery of the shark. Steve Alten's Meg: A Novel of Deep Terror has portrayed the inaccuracy that it lived with dinosaurs with its prologue and cover artwork depicting megalodon killing a Tyrannosaurus in the sea. The sequels to the book also star megalodon: The Trench, Meg: Primal Waters, Meg: Hell's Aquarium, and Meg: Origins.
Animal Planet's pseudo-documentary Mermaids: The Body Found included an encounter 1.6 mya between a pod of mermaids and a megalodon. Later, in August 2013, the Discovery Channel opened its annual Shark Week series with another film for television, Megalodon: The Monster Shark Lives, a controversial docufiction about the creature that presented alleged evidence in order to suggest that megalodon was still alive. This program received criticism for being completely fictional; for example, all of the supposed scientists depicted were paid actors. In 2014, Discovery re-aired The Monster Shark Lives, along with a new one-hour program, Megalodon: The New Evidence, and an additional fictionalized program entitled Shark of Darkness: Wrath of Submarine, resulting in further backlash from media sources and the scientific community.
There have been a few alleged sightings of large sharks, purportedly megalodon, measuring anywhere from 10 to 90 meters (40 to 300 ft) throughout the 1900s, however they all lack supporting evidence. More likely they were misidentified whale sharks. One Polynesian myth regards a 30-meter (100 ft) shark called Lord of the Deep, but this is probably an exaggeration of a whale shark. Reports of supposed fresh megalodon teeth, such those made by HMS Challenger in 1873 which were erroneously dated to be around 11,000 to 24,000 years old, are probably teeth that were well-preserved by a thick mineral-crust precipitate of manganese dioxide, and so had a lower decomposition rate and retained a white color during fossilization. Fossil megalodon teeth can vary in color from off-white to dark browns and greys and may have been redeposited into a younger stratum. The claims that megalodon could remain elusive in the depths, similar to the megamouth shark which was discovered in 1976, are unlikely as the shark evolved around warm coastal waters and probably could not survive in the cold and nutrient-poor deep sea environment.
- Agassiz, Louis (1833). Recherches sur les poissons fossiles [Research on the fossil fishes] (in French). Neuchatel: Petitpierre. p. 41.
- Carcharocles megalodon at fossilworks.org (retrieved 28 August 2017)
- Eastman, C. R. (1904). Maryland Geological Survey. 2. Baltimore, Maryland: Johns Hopkins University. p. 82.
- Haven, Kendall (1997). 100 Greatest Science Discoveries of All Time. Westport, Connecticut: Libraries Unlimited. pp. 25–26. ISBN 978-1-59158-265-6. OCLC 230807846.
- Kuang-Tai, Hsu (2009). "The Path to Steno's Synthesis on the Animal Origin of Glossopetrae". In Rosenburg, G. D. The Revolution in Geology from the Renaissance to the Enlightenment. 203. Boulder, Colorado: Geological Society of America. ISBN 978-0-8137-1203-1. OCLC 608657795.
- Eilperin, J. (2012). Demon Fish. Pantheon Books. p. 43. ISBN 978-0-7156-4352-5.
- Nyberg, K. G.; Ciampaglio C. N.; Wray G. A. (2006). "Tracing the ancestry of the great white shark, Carcharodon carcharias, using morphometric analyses of fossil teeth". Journal of Vertebrate Paleontology. 26 (4): 806–814. doi:10.1671/0272-4634(2006)26[806:TTAOTG]2.0.CO;2.
- μέγας. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project
- ὀδούς. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project
- 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. ISSN 0038-2353. doi:10.1007/BF02988410.
- Renz, Mark (2002). Megalodon: Hunting the Hunter. Lehigh Acres, Florida: PaleoPress. pp. 1–159. ISBN 978-0-9719477-0-2. OCLC 52125833.
- Hideo, Habe; Mastatoshi, Goto; Naotomo, Kaneko (2004). "Age of Carcharocles megalodon (Lamniformes: Otodontidae): A review of the stratigraphic records". The Palaeontological Society of Japan. 75 (75): 7–15.
- 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.
- Pimiento, C.; MacFadden, B. J.; Clements, C. F.; Varela, S.; Jaramillo, C.; Velez-Juarbe, J.; Silliman, B. R. (2016). "Geographical distribution patterns of Carcharocles megalodon over time reveal clues about extinction mechanisms". Journal of Biogeography. 43 (8): 1645–1655. doi:10.1111/jbi.12754.
- Pimiento, C.; Clements, C. F. (2014). "When Did Carcharocles megalodon Become Extinct? A New Analysis of the Fossil Record". PLoS ONE. 9 (10): e111086. Bibcode:2014PLoSO...9k1086P. PMID 25338197. doi:10.1371/journal.pone.0111086.
- Klimley, Peter; Ainley, David (1996). "Evolution". Great White Sharks: The Biology of Carcharodon carcharias. San Diego, California: Academic Press. ISBN 978-0-12-415031-7. OCLC 212425118.
- Pimiento, Catalina; Ehret, Dana J.; MacFadden, Bruce J.; Hubbell, Gordon (2010). Stepanova, Anna, ed. "Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama". PLoS ONE. 5 (5): e10552. Bibcode:2010PLoSO...510552P. PMC . PMID 20479893. doi:10.1371/journal.pone.0010552.
- Bendix-Almgreen, Svend Erik (1983). "Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn" (PDF). Bulletin of the Geological Society of Denmark. Geologisk Museum. 32: 1–32.
- Ehret D. J.; Hubbell G.; Macfadden B. J. (2009). "Exceptional preservation of the white shark Carcharodon from the early Pliocene of Peru". Journal of Vertebrate Paleontology. 29 (1): 1–13. JSTOR 20491064. doi:10.1671/039.029.0113.
- Shimada, K.; Chandler, R. E.; Lam, O. L. T.; Tanaka, T.; Ward, D. J. (2016). "A new elusive otodontid shark (Lamniformes: Otodontidae) from the lower Miocene, and comments on the taxonomy of otodontid genera, including the 'megatoothed' clade". Historical Biology. 29 (5): 1–11. doi:10.1080/08912963.2016.1236795.
- Pimiento, C.; Balk, M. A. (2015). "Body-size trends of the extinct giant shark Carcharocles megalodon: a deep-time perspective on marine apex predators". Paleobiology. 41 (3): 479–490. PMC . PMID 26321775. doi:10.1017/pab.2015.16.
- Andres, Lutz (2002). "C. megalodon — Megatooth Shark, Carcharodon versus Carcharocles". fossilguy.com. Retrieved 16 January 2008.
- Siverson, Mikael; Johan Lindgren; Michael G. Newbrey; Peter Cederström; 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. Archived from the original on 19 October 2013.
- Cappetta, H. (1987). "Mesozoic and Cenozoic Elasmobranchii". Handbook of Paleoichthyology. 3B. München, Germany: Friedrich Pfeil. ISBN 978-3-89937-046-1. OCLC 829906016.
- Glikman, Leonid Sergeevič (1964). Akuly paleogena i ich stratigrafičeskoe značenie. p. 229.
- "Could Megalodon Have Looked Like a BIG Sandtiger Shark?". Biology of Sharks and Rays. Retrieved 2 September 2017.
- 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" (PDF). Caribbean Journal of Science. 44 (3): 279–286. doi:10.18475/cjos.v44i3.a2. Archived from the original on 20 July 2011.
- Papson, Stephen (1992). "Cross the Fin Line of Terror". Journal of American Culture. 15 (4): 67–81. doi:10.1111/j.1542-734X.1992.1504_67.x.
- Antunes, M. T.; Legoinha, P.; Balbino, A. C. (2015). "Megalodon, mako shark and planktonic foraminifera from the continental shelf off Portugal and their age". Geologica Act. 13: 181–190. doi:10.1344/GeologicaActa2015.13.3 (inactive 2017-10-14).
- Prothero, D. R. (2015). "Mega-Jaws". The Story of Life in 25 Fossils. New York, New York: Columbia University Press. ISBN 978-0-231-17190-8. OCLC 897505111.
- 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?" (PDF). Journal of Zoology. 276 (4): 336–342. doi:10.1111/j.1469-7998.2008.00494.x.
- Jacoby, D. M. P.; Siriwat, P.; Freeman, R.; Carbone, C. (2015). "Is the scaling of swim speed in sharks driven by metabolism?". Biology Letters. 12 (10): 20150781. PMC . doi:10.1098/rsbl.2015.0781.
- Ferrón, H. G. (2017). "Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks". PLoS One. 12 (9): e0185185. PMC . PMID 28938002. doi:10.1371/journal.pone.0185185.
- Helfman, G.; Burgess, G. H. (2014). Sharks: The Animal Answer Guide. Baltimore, Maryland: Johns Hopkins University Press. p. 19. ISBN 978-1-4214-1310-5. OCLC 903293986.
- 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.
- Shimada, Kenshu (2002). "The relationship between the tooth size and total body length in the white shark, Carcharodon carcharias (Lamniformes: Lamnidae)". Journal of Fossil Research. 35 (2): 28–33.
- 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.
- "Vito Bertucci: Megalodon Man". theworldslargestsharksjaw.com. Retrieved 31 August 2017.
- Mustain, A. (2011). "For Sale: World's Largest Shark Jaws". LiveScience. Retrieved 31 August 2017.
- Uyeno, T.; Sakamoto, O.; Sekine, H. (1989). "The description of an almost compete tooth set of Carcharodon megalodon from a Middle Miocene bed in Saitama Prefecture, Japan". Saitama Museum of Natural History Bulletin. 7: 73–85.
- "Megalodon Shark Facts and Information: The Details". fossilguy.com. Retrieved 18 September 2017.
- Roesch, B. S. (1998). "A Critical Evaluation of the Supposed Contemporary Existence of Carcharocles megalodon". The Cryptozoology Review. 3 (2): 14–24. Archived from the original on 21 October 2013.
- Fitzgerald, Erich (2004). "A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia" (PDF). Memoirs of Museum Victoria. 61 (2): 183–208. Archived from the original (PDF) on 23 August 2008.
- 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.
- Martin, J. E.; Tacail, T.; Sylvain, A.; Catherine, G.; Vincent, B. (2015). "Calcium isotopes reveal the trophic position of extant and fossil elasmobranchs". Chemical Geology. 415: 118–125. Bibcode:2015ChGeo.415..118M. doi:10.1016/j.chemgeo.2015.09.011.
- Collareta, A.; Lambert, O.; Landini, W.; Di Celma, C.; Malinverno, E.; Varas-Malca, R.; Urbina, M.; Bianucci, G. (2017). "Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru". Palaeogeography, Palaeoclimatology, Palaeoecology. 469: 84. doi:10.1016/j.palaeo.2017.01.001.
- Morgan, Gary S. (1994). "Whither the giant white shark?" (PDF). Paleontology Topics. Paleontological Research Institution. 2 (3): 1–2.
- Landini, W.; Altamirano-Sera, A.; Collareta, A.; Di Celma, C.; Urbina, M.; Bianucci, G. (2017). "The late Miocene elasmobranch assemblage from Cerro Colorado (Pisco Formation, Peru)". Journal of South American Earth Sciences. 73: 168–190. Bibcode:2017JSAES..73..168L. doi:10.1016/j.jsames.2016.12.010.
- Lambert, O.; Bianucci, G.; Post, P.; de Muizon, C.; Salas-Gismondi, R.; Urbina, M.; Reumer, J. (2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature. 466 (7302): 105–108. Bibcode:2010Natur.466..105L. PMID 20596020. doi:10.1038/nature09067.
- Compagno, Leonard J. V. (1989). "Alternative life-history styles of cartilaginous fishes in time and space". Environmental Biology of Fishes. 28 (1–4): 33–75. doi:10.1007/BF00751027.
- Ferretti, Francesco; Boris Worm; Gregory L. Britten; Michael R. Heithaus; Heike K. Lotze1 (2010). "Patterns and ecosystem consequences of shark declines in the ocean" (PDF). Ecology Letters. 13 (8): 1055–1071. PMID 20528897. doi:10.1111/j.1461-0248.2010.01489.x. Archived from the original on 6 July 2011. Retrieved 19 February 2011.
- Bianucci, Giovanni; Walter, Landini (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.
- Heyning, John; Dahlheim, Marilyn (1988). "Orcinus orca" (PDF). Mammalian Species. 304 (304): 1–9. JSTOR 3504225. doi:10.2307/3504225.
- "Paleoecology of Megalodon and the White Shark". Biology of Sharks and Rays. Retrieved 1 October 2017.
- Tanke, Darren; Currie, Philip (1998). "Head-Biting Behaviour in Theropod Dinosaurs: Paleopathological Evidence" (PDF). Gaia N°15: 168.
- Godfrey, S. J.; Altman, J. (2005). "A Miocene Cetacean Vertebra Showing a Partially Healed Compression Factor, the Result of Convulsions or Failed Predation by the Giant White Shark, Carcharodon megalodon" (PDF). Jeffersoniana (16): 1–12.
- 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.
- "Identifican en Canarias fósiles de 'megalodón', el tiburón más grande que ha existido" [Identifying Canary fossils of 'megalodon', the largest shark that ever lived] (in Spanish). 2013. Retrieved 29 August 2017.
- Dulvy, N. K.; Reynolds, J. D. (1997). "Evolutionary transitions among egg-laying, live-bearing and maternal inputs in sharks and rays". Proceedings of the Royal Society B: Biological Sciences. 264 (1386): 1309–1315. doi:10.1098/rspb.1997.0181.
- Godfrey, Stephen (2004). "The Ecphora" (PDF). The Newsletter of Calvert Marine Museum Fossil Club. 19 (1): 1–13. Archived from the original on 10 December 2010.
- 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): 253–260. doi:10.1002/oa.1199.
- "The Extinction of Megalodon". Biology of Sharks and Rays. Retrieved 31 August 2017.
- 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. The University of Chicago. 104 (2): 143–162. Bibcode:1996JG....104..143A. doi:10.1086/629811.
- Pimiento, C.; Griffin, J. N.; Clements, C. F.; Silvestro, D.; Varela, S.; Uhen, M. D.; Jaramillo, C. (2017). "The Pleistocene Marine Megafauna Extinction and its Impact on Functional Diversity". Nature Ecology and Evolution. 1 (8): 1100–1106. doi:10.1038/s41559-017-0223-6.
- Reilly, Michael (29 September 2009). "Prehistoric Shark Nursery Spawned Giants". Discovery News. Archived from the original on 10 March 2012. Retrieved 23 November 2013.
- 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. JSTOR 4524731. doi:10.1671/2401.
- Antunes, Miguel Telles; Balbino, Ausenda Cáceres (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. 25 (1): 1–6.
- Slater, G. J.; Goldbogen, J. A.; Pyenson, N. D. (2017). "Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics". Proceedings of the Royal Society B: Biological Sciences. 284 (1855): 20170546. PMC . doi:10.1098/rspb.2017.0546.
- Collareta, A.; Lambert, O.; Landini, W.; Bianucci, G. (2017). "Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru". Palaeogeography, Palaeoclimatology, Palaeoecology. 469: 84–91. doi:10.1016/j.palaeo.2017.01.001.
- Sylvain, Adnet; A. C. Balbino; M. T. Antunes; J. M. Marín-Ferrer (2010). "New fossil teeth of the White Shark (Carcharodon carcharias) from the Early Pliocene of Spain. Implication for its paleoecology in the Mediterranean". Neues Jahrbuch für Geologie und Paläontologie. 256 (1): 7–16. doi:10.1127/0077-7749/2009/0029.
- Weinstock, J. A. (2014). The Ashgate Encyclopedia of Literary and Cinematic Monsters. Farnham, United Kingdom: Routledge. pp. 107–108. ISBN 978-1-4094-2562-5. OCLC 874390267.
- >Emmer, Rick (2010). Megalodon: Fact Or Fiction?. Infobase Publishing. ISBN 978-1-4381-3210-5.
- "The Third Most Deadly Sea". Sea Monsters. Season 1. Episode 3. 23 September 2003. BBC.
- "Deep Sea Killers". Jurassic Fight Club. Season 1. Episode 5. 26 August 2008. History Channel.
- Ethan Spaulding (Director) (2015). Justice League: Throne of Atlantis (Motion picture). Warner Bros. Animation.
- Shepard, J. (2007). "Tedford and the Megalodon". In Chabon, M. McSweeney's Mammoth Treasury of Thrilling Tales. Knopf Doubleday Publishing Group. ISBN 978-0-307-42682-6. OCLC 1002088939.
- Alten, S. (2011). "Megalodon". Meg: A Novel of Deep Terror. Gere Donovan Press. ISBN 978-1-936666-21-8.
- Sid Bennett (Director) (27 May 2012). Mermaids: The Body Found (Motion picture). Animal Planet.
- "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.
- Winston, B.; Vanstone, G.; Chi, W. (2017). "A Walk in the Woods". The Act of Documenting: Documentary Film in the 21st Century. New York, New York: Bloomsbury Publishing. ISBN 978-1-5013-0918-2. OCLC 961183719.
- Flanagin, J. (2014). "Sorry, Fans. Discovery Has Jumped the Shark Week.". New York Times. Retrieved 16 August 2014.
- "Does Megalodon Still Live?". Biology of Sharks and Rays. Retrieved 2 October 2017.
- Kent, Bretton W. (1994). Fossil Sharks of the Chesapeake Bay Region. Columbia, Maryland: Egan Rees & Boyer, Inc. pp. 1–146. ISBN 978-1-881620-01-3. OCLC 918266672.
- Dickson, K. A.; Graham, J. B. (2004). "Evolution and consequences of endothermy in fishes". Physiological and Biochemical Zoology. 77 (6): 998–1018. PMID 15674772. doi:10.1086/423743.
|Wikimedia Commons has media related to Carcharodon megalodon.|
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|Wikispecies has information related to: Otodus (Megaselachus) megalodon|
- The rise of super predatory sharks
- 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.
- Megalodon article on prehistoric-wildlife.com
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- Megalodon Giant Shark – National Geographic (full documentary)
- on YouTube
- on YouTube depicting aggressive interspecific interactions between megalodon and a pod of killer sperm whales (Brygmophyseter shigensis) from History Channel
- North Carolina Museum of Natural Sciences on YouTube
- on YouTube with comments on its extinction.
- on YouTube
- on YouTube (featuring expert Dana Ehret)
- on YouTube (featuring expert Mikael Siverson)
- on YouTube (featuring expert Bretton Kent)
- on YouTube (Megalodon extinction discussed)