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  1. 1 The word megalodon means “giant tooth”: it is made from Greek root words. Britannica
  2. 2 The Natural History Museum translates the name simply as ‘large tooth’. NHM
  3. 3 Its scientific name today is Otodus megalodon. It used to be called Carcharodon megalodon or Carcharocles megalodon. NHM
  4. 4 Megalodon was first described in 1835 by the Swiss-born naturalist Louis Agassiz, who named it Carcharodon megalodon. Britannica
  5. 5 It is considered the largest shark, and the largest fish, that ever lived. Britannica
  6. 6 The Natural History Museum is a little more careful: the biggest shark in the world, and one of the largest fish ever to exist. NHM
  7. 7 The earliest megalodon fossils date to 23 million years ago, and it became extinct 3.6 million years ago. NHM
  8. 8 Smithsonian Ocean says it lived roughly 23 to 3.6 million years ago in nearly every corner of the ocean. Smithsonian
  9. 9 Britannica dates megalodon fossils from the early Miocene, which began 23.03 million years ago, to the end of the Pliocene, 2.58 million years ago. Britannica
  10. 10 Like other sharks, its skeleton was mostly cartilage, the same bendy material as in your nose and ears. Cartilage is lighter than bone but very hard to fossilise. Smithsonian
  11. 11 So most of what we know comes from its teeth, its vertebrae (which contain calcium and so are preserved) and fossilised poop. Smithsonian
  12. 12 No one has ever found a complete megalodon skeleton. NHM
  13. 13 Britannica says it is known from hundreds of fossil teeth, two vertebral columns and a handful of single vertebrae. Britannica
  14. 14 Fossil megalodon vertebrae about the size of a dinner plate have been found. NHM
  15. 15 A megalodon skull reported from Peru apparently has a crushed braincase, all its teeth and a short string of vertebrae, but the museum’s expert had not yet seen good pictures of it. NHM
  16. 16 Its body shape is worked out from living sharks, because the skeleton is missing. Smithsonian
  17. 17 Most reconstructions show megalodon as an enormous great white shark. The Natural History Museum says this is now believed to be wrong. NHM
  18. 18 Scaled up to megalodon’s size, a great white would probably struggle to swim, so scientists suggest a much slimmer body, perhaps shaped like a lemon shark’s. NHM
  19. 19 It probably also had a much shorter snout than a great white, a flatter jaw and extra-long pectoral fins to carry its weight. NHM
  20. 20 A 2025 study by 29 fossil shark experts concluded that megalodon could have had a slender body, because a stout, great-white-like body at that size would have cost too much energy to push through the water. Shimada et al. 2025
  21. 21 Britannica still gives the older picture as well: a bulky, torpedo-shaped fish with a cone-shaped snout, large fins and a crescent-shaped tail, like a great white. Britannica
  22. 22 A 2020 study scaled up five living relatives and suggested that a 16 m megalodon probably had a head about 4.65 m long, a dorsal fin about 1.62 m tall and a tail about 3.85 m high. Cooper et al. 2020
  23. 23 The 2025 authors call their ideas working hypotheses: reference points for future studies, not final answers. Shimada et al. 2025
  24. 24 For a long time people thought megalodon was a relative of the great white. The museum’s expert says we now know it came from a different lineage of shark, and was the last member of it. NHM
  25. 25 The oldest definite ancestor of megalodon is Otodus obliquus, a 55-million-year-old shark that grew to about 10 metres. NHM
  26. 26 The lineage may go back to a Cretalamna shark 105 million years ago, which would make it more than 100 million years old. NHM
  27. 27 Smithsonian Ocean dates the start of megalodon’s lineage to about 60 million years ago, and says even its earliest member was longer than a great white. Smithsonian
  28. 28 Megalodon belonged to the lamnoid sharks (Lamniformes), the group that also includes great whites, makos and threshers. Smithsonian
  29. 29 Smithsonian Ocean says modern studies show megalodon was more closely related to an ancestor of mako sharks than to the great white. Smithsonian
  30. 30 Britannica places it in the extinct family of megatooth sharks, the Otodontidae. Britannica
  31. 31 Britannica notes that the debate is not over: some palaeontologists still put megalodon in the same lineage as the great white because of their serrated teeth, while others put it with the megatooth sharks. Britannica
  32. 32 Their similar serrated teeth may be convergent evolution: similar features evolving separately in different lineages. Britannica
  33. 33 The great white’s ancestor lived at the same time as megalodon, and some scientists think the two competed. NHM
  34. 34 A 2020 study points out that the two species probably belong to different families, so using the great white as the only model for megalodon’s size can be a problem. Cooper et al. 2020
  35. 35 Megalodon teeth can reach 18 centimetres long. NHM
  36. 36 The largest megalodon tooth ever found is almost 18 cm long. Great white teeth are usually about 5 cm. NHM
  37. 37 Britannica gives the largest known tooth as 17.8 cm, almost three times the usual 5.4 cm of a great white’s tooth. Britannica
  38. 38 Smithsonian Ocean says its teeth were as large as an adult human’s hand, and some are over 18 cm tall. Smithsonian
  39. 39 Like a great white’s, megalodon teeth are triangular, serrated and symmetrical. Britannica
  40. 40 But they are bigger and thicker, their serrations are evenly spaced, and they have a bourlette: a darker, chevron-shaped band near the root. Britannica
  41. 41 Its jaws held 276 teeth. NHM
  42. 42 Its teeth sat in several rows. Each time one fell out, a tooth from the row behind moved forward to replace it, like a conveyor belt. NHM, still alive?
  43. 43 Sharks make new teeth all their lives. Depending on what they eat, they can lose a set every one to two weeks and get through up to 40,000 teeth. NHM
  44. 44 So shark teeth are always raining down onto the sea floor, which raises the chance that some become fossils. NHM
  45. 45 Teeth are also the hardest part of a shark, which is why almost all megalodon fossils are teeth. NHM
  46. 46 Megalodon teeth have been found on every continent except Antarctica. NHM
  47. 47 Lots turn up off the east coast of North America: along the coasts and in saltwater creeks and rivers of North Carolina, South Carolina and Florida. NHM
  48. 48 They are also quite common off Morocco and parts of Australia. NHM
  49. 49 In the UK they have been found near Walton-on-the-Naze in Essex, but they are extremely rare here and usually poor quality. NHM
  50. 50 In the UK, Otodus megalodon teeth occasionally wash out of the Red Crag, one of the younger rocks of East Anglia. NHM
  51. 51 Because sharks shed teeth all the time, megalodon teeth can be found scattered on coastal beaches or just offshore. Smithsonian
  52. 52 Body lengths are estimated from tooth size, using the link between tooth size and body size in great whites and other living relatives. Britannica
  53. 53 A 2022 study used upper front teeth, which its authors say give better size estimates than side teeth. NHM news, 2022
  54. 54 The equations for turning teeth into body length were updated in 2021, using a largely complete set of teeth, after earlier estimates were found to vary wildly. NHM news, 2022
  55. 55 Older length estimates, based on tooth size, suggest a maximum of 15 to 18 metres. NHM
  56. 56 A 2025 study by 29 fossil shark experts found that megalodon may have grown up to 24.3 metres long. NHM
  57. 57 That is about four times longer than the largest recorded great white, and a few metres longer than the biggest whale shark, measured at 18.8 metres. NHM
  58. 58 It would make megalodon only a metre shorter than Hope, the blue whale skeleton hanging in the museum’s Hintze Hall. NHM
  59. 59 The 24.3 m figure comes from nearly complete and partial backbones found in Belgium and Denmark, compared with 170 kinds of living and extinct sharks to work out head and tail sizes. NHM
  60. 60 The 2025 paper itself says megalodon possibly reached about 24.3 m in length. Shimada et al. 2025
  61. 61 A shark that size may have weighed about 94 tonnes and cruised at around 2.1 to 3.5 km an hour. Shimada et al. 2025
  62. 62 Smithsonian Ocean says the largest were roughly 60 feet (about 18 m) long, perhaps up to 50 tons, the size and weight of a railway carriage. Smithsonian
  63. 63 Smithsonian Ocean also says females were bigger on average, about 13 to 17 m, and males about 10 to 14 m. Smithsonian
  64. 64 It calls megalodon roughly up to three times the length of a modern great white. Smithsonian
  65. 65 Britannica says grown-up megalodons averaged 13 to 14 metres, with the largest up to an estimated 24.3 metres. Britannica
  66. 66 Britannica gives adult weights from about 30 tonnes to more than 65 tonnes. Most great whites weigh 680 to 1,800 kg. Britannica
  67. 67 A 2022 study found that megalodons living in cooler water tended to grow bigger than those in warmer water. NHM news, 2022
  68. 68 Its lead author said the common idea that megalodon reached 18 to 20 metres should apply mainly to populations in cooler seas. NHM news, 2022
  69. 69 Only estimates are possible, because nearly all megalodon fossils are teeth. NHM news, 2022
  70. 70 Reading the growth bands in a backbone, the 2025 study estimated a size at birth of 3.6 to 3.9 metres. Shimada et al. 2025
  71. 71 The Natural History Museum puts it simply: newborn megalodons may have been up to 3.9 metres long. NHM
  72. 72 Britannica, using young sharks’ teeth, says newborns may have been at least 2 metres long. Britannica
  73. 73 Its jaws are estimated to have opened 2.7 by 3.4 metres: big enough to swallow two adults side by side, or a London taxi. NHM
  74. 74 Britannica gives its bite diameter as 3 metres, several times that of an average great white. Britannica
  75. 75 A human bite has been measured at around 1,317 newtons and a great white’s predicted at 18,216 N. Megalodon’s is estimated at 108,514 to 182,201 N. NHM
  76. 76 Smithsonian Ocean says a megalodon bite could have reached about 40,000 pounds of force, which would be the strongest bite in the whole animal kingdom. Smithsonian
  77. 77 Museum jaws are often shown opened wider than the living shark could manage, so that the teeth show. Smithsonian
  78. 78 With its big serrated teeth megalodon ate meat: most likely whales and large fish, and probably other sharks. NHM
  79. 79 Its prey ranged from dolphins to animals as big as humpback whales. NHM
  80. 80 Smithsonian Ocean lists toothed and baleen whales, seals, sea cows and sea turtles, and probably fish and other sharks too. Smithsonian
  81. 81 Britannica adds that the young probably went after smaller prey while adults hunted bigger whales. Britannica
  82. 82 Some fossil whale bones carry cut marks from megalodon teeth, and some even hold the broken-off tips of teeth. NHM
  83. 83 Sometimes a whole megalodon tooth is found stuck in a whale bone. Smithsonian
  84. 84 From tooth marks, scientists think it struck larger prey such as small whales in the chest, punching through their ribs, and may have rammed smaller prey to stun it. Smithsonian
  85. 85 Megalodon was an apex predator. Fully grown ones probably had no predators, but the young may have been at risk from other big sharks such as great hammerheads. Britannica
  86. 86 Megalodon was adapted to warm tropical and subtropical seas around the globe. NHM
  87. 87 Its fossils come from shallow tropical and temperate seas along the coasts and continental shelves of every continent except Antarctica. Britannica
  88. 88 Smithsonian Ocean says it lived in most of the ocean except near the poles, with the most northerly fossils found off Denmark. Smithsonian
  89. 89 Like great whites, megalodon was probably not entirely cold-blooded: heat from its swimming muscles kept parts of its body warmer than the water, which is called regional endothermy. Britannica
  90. 90 The 2025 authors say its body temperature was similar to, or maybe slightly higher than, that of great whites. Shimada et al. 2025
  91. 91 Megalodon is thought to have given birth to live young. Britannica
  92. 92 The 2025 study supports the idea that megalodon pups grew inside the mother and ate unhatched eggs there, as some living sharks do. Shimada et al. 2025
  93. 93 A 2010 study described the first definite megalodon nursery, in the Gatun Formation of Panama, about 10 million years old. Pimiento et al. 2010
  94. 94 Most of the teeth there were very small, from young sharks and newborns estimated at 2 to 10.5 metres long. Pimiento et al. 2010
  95. 95 Smithsonian Ocean lists nursery sites in Panama, Maryland, the Canary Islands and Florida. Smithsonian
  96. 96 A 2022 study questioned the nurseries: sites full of small teeth may just be places where warm water meant the sharks grew smaller. NHM news, 2022
  97. 97 The 2025 study also found nursery areas less likely to have been needed. Shimada et al. 2025
  98. 98 Megalodon teeth are only found in sea rocks 20 to 3.6 million years old. None younger has ever been found, so it went extinct 3.6 million years ago. NHM, still alive?
  99. 99 The same page talks of megalodon’s 16-million-year existence. NHM, still alive?
  100. 100 The Natural History Museum also says megalodon was extinct by the end of the Pliocene, 2.6 million years ago, and that new evidence from the USA puts the last one at least 3.6 million years ago. NHM
  101. 101 Smithsonian Ocean puts its disappearance from the fossil record around 2.6 million years ago. Smithsonian
  102. 102 A 2019 study checked every late record on the Pacific coast of North America and found the youngest reliable ones are early Pliocene, pointing to extinction about 3.6 million years ago. Boessenecker et al. 2019
  103. 103 Re-analysing a wider set of records gave a median extinction date of 3.51 million years ago, older than the 2.6 million years proposed before. Boessenecker et al. 2019
  104. 104 The same study says the extinction may not have happened at the same time everywhere. Boessenecker et al. 2019
  105. 105 The planet was cooling. As adult megalodons depended on warm water, falling sea temperatures probably meant a big loss of habitat. NHM
  106. 106 Up to a third of all large sea animals, including 43% of turtles and 35% of seabirds, may have died out as temperatures cooled and numbers at the base of the food chain plummeted. NHM
  107. 107 Its prey may have died out too, or moved into cooler water where the sharks could not follow. NHM
  108. 108 As ice formed at the poles and sea level fell, the shallow coastal waters where pups were born would have been lost. NHM
  109. 109 Smithsonian Ocean links the end to the rising Isthmus of Panama, which cut the Caribbean off from the nutrient-rich Pacific, and the loss of prey. Smithsonian
  110. 110 Competition with great white sharks for food may also have played a part. Studies of fossil teeth show that what the two ate overlapped. NHM
  111. 111 A 2022 study of zinc in fossil teeth found that, in the early Pliocene, great whites and megalodons living in the same places fed at a similar level in the food chain. McCormack et al. 2022
  112. 112 The 2025 study supports the idea that the arrival of the great white in the early Pliocene was at least partly to blame, through competition for food. Shimada et al. 2025
  113. 113 The 2019 study also suggests that ocean changes and cooling broke up its range, alongside competition with the newly evolved great white. Boessenecker et al. 2019
  114. 114 Exactly why megalodon went extinct is still being worked out, but there is mounting evidence for a mix of changing climate, falling prey numbers and competition. NHM, still alive?
  115. 115 It is definitely not alive in the deep ocean. If an animal that big were still out there, we would know about it. NHM
  116. 116 There have been no confirmed sightings of a living or dead modern megalodon. NHM, still alive?
  117. 117 No living sea animals have been seen with megalodon-sized bite marks. NHM, still alive?
  118. 118 Below about 3,000 metres there is barely any food, and no sharks live much deeper than that. NHM, still alive?
  119. 119 As a warm-water species, it could not survive in the cold water of the deep sea anyway. NHM
  120. 120 A 2013 US documentary, Megalodon: The Monster Shark Lives, used faked photos and footage, and its ‘scientists’ were hired actors. NHM, still alive?
  121. 121 Two megalodon teeth dredged up by the Challenger expedition in 1875 were claimed in 1959 to be only tens of thousands of years old. That claim was disproved in the 1970s. NHM, still alive?
  122. 122 A 1918 report from fishermen off eastern Australia described a shark 31 to 95 metres long stealing lobster pots. It may have been a whale shark. NHM, still alive?
  123. 123 The short name megalodon is also the name of a genus of clams, which can cause confusion among scientists. Smithsonian
  124. 124 Great whites have been recorded diving to around 1,000 metres. NHM, still alive?
  125. 125 Whale sharks, up to 18 metres long, are rarely seen, yet we know they are the largest living sharks. NHM, still alive?