Otodus megalodon (pronounced MEH-guh-luh-don; meaning "big tooth"), also called megalodon, was a giant mackerel shark that lived about 23 to 3.58 million years ago, during the Early Miocene to Early Pliocene periods. Scientists once thought megalodon was closely related to the great white shark (Carcharodon carcharias) and belonged to the Lamnidae family. However, it has since been reclassified into the extinct Otodontidae family, which separated from the great white shark during the Early Cretaceous period.
Megalodon was one of the largest and strongest predators in Earth's history, but scientists know very little about it because most evidence comes from incomplete remains. Its exact size and body shape are still debated. Some studies suggest it could have grown up to 16.1 to 24.3 meters (53 to 80 feet) long, though most individuals likely reached about 10.5 meters (34 feet). Its teeth were thick and strong, designed to grab prey and crush bones. Its jaws could produce a bite force of up to 108,500 to 182,200 newtons (24,390 to 40,960 pounds-force).
Megalodon likely played a major role in shaping ancient ocean ecosystems. Fossils show it lived in many parts of the world. It probably hunted large animals, such as whales, seals, and sea turtles. Young megalodons lived in warm coastal areas and ate fish and small whales. Unlike the great white shark, which attacks prey from below, megalodon likely used its powerful jaws to break through the chest of its prey and damage its heart and lungs.
Megalodon faced competition from other whale-eating animals, such as Livyatan and large sperm whales, as well as early killer whales (Orcinus). However, some early killer whales, like Orcinus citoniensis, may not have been direct competitors because they likely ate smaller fish and squid instead of large marine mammals. Megalodon preferred warmer waters, and changes in ocean temperatures during the ice ages, along with falling sea levels that reduced suitable habitats for young sharks, may have contributed to its decline. A decrease in the number of baleen whales and their movement toward colder regions may have also reduced megalodon’s food supply. Its extinction occurred around the same time that baleen whales began growing larger.
Classification
Megalodon teeth have been found and used since ancient times. Pre-Columbian cultures in the Americas valued them for their size and sharp edges, using them to make tools like arrowheads, knives, jewelry, and items used in funerals. Some groups, like the Sitio Conte societies in Panama, likely used them mainly for special rituals. In the Chesapeake Bay, the Algonquin people mined megalodon teeth as early as 430 BC and traded them with the Adena culture in Ohio. The first written description of megalodon teeth came from Pliny the Elder in 73 AD, who called them "glossopetrae" or "tongue stones," believing they were petrified human tongues that fell from the sky during lunar eclipses. Later, a 12th-century Maltese tradition claimed these stones were the tongues of serpents turned to stone by Saint Paul, and they were thought to have healing powers. By the late 1200s to 1500s, European nobles used megalodon teeth as protective amulets and in tableware, believing they could remove poisons. By the 1600s, some Europeans even ate megalodon teeth as part of a medicine called Goa stones.
Some people began to suspect that glossopetrae were actually shark teeth as early as 1554, when André Thevet called the idea a rumor. In 1616, Fabio Colonna, an Italian naturalist, compared a megalodon tooth to a great white shark’s tooth and argued they were both shark teeth. He burned samples of glossopetrae and saw carbon, suggesting they had an organic origin. However, many people still believed the stones were not shark teeth, partly because some were found far from the ocean. In the late 1600s, scientists like Robert Hooke, John Ray, and Niels Steensen (Latinized as Nicholas Steno) studied the issue again. Steensen’s research, based on a great white shark’s head he dissected in 1666, helped link glossopetrae to sharks. He also proposed that rock layers containing megalodon teeth had once been underwater, later rising above sea level due to geological changes.
Swiss naturalist Louis Agassiz gave megalodon its scientific name in 1833–1843. He first called it Carcharias megalodon in 1835, naming it after the Greek words for "big tooth." Later, in 1843, he changed the name to Carcharodon megalodon because its teeth were much larger than those of the sand tiger shark. Agassiz mistakenly grouped some megalodon teeth with other species, but these names are now considered outdated.
Megalodon lived as far back as the Late Oligocene, about 28 million years ago, though some evidence suggests it appeared as recently as 16 million years ago. It likely went extinct at the end of the Pliocene, around 3.6 million years ago. Scientists debate its classification, with some placing it in the Otodontidae family and others in the Carcharodon genus. Most researchers now believe megalodon is more closely related to mako sharks than to great white sharks, as their teeth have different features.
The genus Carcharocles includes four species: C. auriculatus, C. angustidens, C. chubutensis, and C. megalodon. Over time, these sharks evolved larger, more triangular teeth with finer serrations, likely adapting to hunt larger prey like whales. The genus Carcharocles was first proposed in 1923, and megalodon was later placed in this group. Earlier, in 1960, French scientist Edgard Casier created the genus Procarcharodon for these sharks, but it is now considered a less official name. Another group, Palaeocarcharodon, was proposed to represent the earliest ancestors of this lineage. Some scientists believe Palaeocarcharodon is unrelated to Carcharocles, while others think it is their ancestor.
Another theory suggests that Carcharocles evolved from the shark Otodus obliquus, which lived from the Paleocene to the Miocene epochs, about 60 to 13 million years ago.
Biology
Megalodon may have looked similar to the great white shark, with a strong build. Its jaws might have been wider and less pointed than the great white’s, and its fins could have been similar in shape but thicker because of its size. Its eyes might have been small and set deep in its head, giving it a "pig-eyed" appearance.
Another idea is that megalodon resembled the whale shark or the basking shark. Its tail fin might have been crescent-shaped, and its anal and second dorsal fins might have been small. A ridge, called a caudal keel, could have been present on either side of the tail. This body shape is common in large aquatic animals like whales and tuna, as it helps reduce water resistance. The shape of the head can vary between species, as most drag-reducing features are near the tail.
In 2024, it was suggested that megalodon had a longer body than previously thought. A study by Shimada et al. (2025) supported this idea by comparing the size of megalodon’s head and tail to its body. They estimated that megalodon could have been much longer than earlier estimates.
In 2023, Shimada and others found megalodon remains with tiny, rough scales called placoid scales. These scales were 0.3 to 0.8 millimeters wide and had ridges spaced apart. The spacing of these ridges matched the swimming speeds of modern sharks, suggesting megalodon might have been warm-blooded in parts of its body but not a fast swimmer. It may have been able to swim quickly for short bursts to catch prey.
Because megalodon fossils are mostly teeth and bones, scientists have had many different size estimates. The great white shark is often used as a comparison because it is the closest living relative. Scientists have used different methods to estimate megalodon’s size based on its teeth and bones.
Estimates of megalodon’s size vary depending on the method used and its body shape. Some studies suggest it could have been 14.2 to 24.3 meters long. One study from 1996 estimated that adult male megalodons might have weighed between 12.6 and 33.9 tons, while females might have weighed between 27.4 and 59.4 tons. Another study in 2015 found that the most common size was about 10.5 meters, based on 544 teeth found in different places and times. Great white sharks are usually around 6 meters long, while the whale shark, the largest living fish, can grow up to 18.8 meters. Scientists think megalodon may have had different sizes and behaviors in different parts of the world because of different environments. Megalodon is believed to have been the largest predatory shark that ever lived.
In 2020, Cooper and others created a 2D model of megalodon by comparing it to other sharks. They estimated that a 16-meter-long megalodon would have had a 4.65-meter-long head, 1.41-meter-tall gill slits, a 1.62-meter-tall dorsal fin, 3.08-meter-long pectoral fins, and a 3.85-meter-tall tail fin. In 2022, they made a 3D model and estimated that a 16-meter-long megalodon would weigh about 61.56 tons. This was higher than earlier estimates. Scientists used a 9.2-meter-long fossil from Belgium to help with these calculations. A megalodon of this size would need 98,175 calories daily, which is 20 times more than a great white shark. Earlier estimates thought this fossil was from a 9.2-meter-long megalodon, but the new model suggests it could have been longer. Shimada et al. (2025) also supported the idea that megalodon had a longer body, estimating its length at 16.4 meters and its weight at 26.9 to 33.7 tons.
A 2015 study linked shark size to swimming speed, suggesting megalodon swam at about 18 kilometers per hour, similar to other large animals like the fin whale. In 2022, Cooper and others calculated that a 16-meter-long megalodon swam at about 5 kilometers per hour, which is faster than other sharks but slower relative to its body length.
Megalodon’s large size may have been influenced by climate, the availability of large prey, and the development of body heat in parts of its body. Some scientists think megalodon was warm-blooded in parts, which would help it swim faster. However, other sharks, like the whale shark, are cold-blooded and filter feeders, while sharks like the great white are warm-blooded in parts and predators. Studies on oxygen in megalodon teeth and the need for fast bursts to hunt suggest megalodon may have been warm-blooded in parts.
In 2020, Shimada and others suggested that megalodon’s large size was due to a process called intrauterine cannibalism, where larger baby sharks eat smaller ones. This would require mothers to be very large to support their young. Males may have also needed to grow large to mate with females, as modern sharks use special organs to attach to females.
The first attempt to recreate megalodon’s jaw was made in 1909 by Bashford Dean, who displayed it at the American Museum of Natural History. His model suggested megalodon could have been 30 meters long, but he overestimated the size of the jaw’s cartilage, making it too tall.
In 1973, John E. Randall, an ichthyologist, used the height of the enamel on megalodon teeth
Paleobiology
Megalodon was a large, powerful shark that hunted a wide variety of animals. Its size, speed, and strong jaws made it an apex predator, meaning it was at the top of the food chain. Studies of calcium and nitrogen isotopes in shark teeth showed that megalodon occupied a higher position in the food chain than the great white shark, at least two levels higher. However, zinc isotopes suggested that megalodon’s position in the food chain decreased in the Atlantic Ocean during the early Pliocene. In North Carolina, megalodon and great white sharks shared a similar position in the food chain.
Dental microwear on megalodon teeth from the Miocene period showed that it had a generalist diet, eating invertebrates, marine mammals, reptiles, bony fish, and other sharks. Fossil evidence confirmed that megalodon hunted many types of whales, including dolphins, small whales, and large baleen whales like fin whales and blue whales. It also hunted seals, sea turtles, and other prey. Whale bones with deep gashes and megalodon teeth found near whale remains support this.
Megalodon’s hunting habits changed as it grew and based on its location. Adult megalodons near Peru likely hunted smaller whales, while juveniles ate more fish. Unlike great white sharks, which target the underbelly of prey, megalodon likely attacked the heart and lungs of large whales. Bite marks on whale bones show it used its thick teeth to break through tough bones. Smaller prey, like certain whales, were rammed from below before being killed.
A 9-meter (30 ft) whale fossil from the Miocene provided evidence that megalodon attacked the rib cage and other tough areas of its prey. Another fossil showed a tooth mark on a sperm whale’s jaw, suggesting a powerful bite that may have broken the whale’s jaw. This is the first known record of a predator-prey interaction between a sperm whale and a megalodon in the fossil record.
During the Pliocene, as larger whales evolved, megalodon adapted its hunting strategies. Bite marks on large whale bones suggest it immobilized them before killing them. Similar marks on other whale fossils indicate the same method.
Studies of megalodon growth rates show it grew twice as fast as modern great white sharks. It stopped growing around 25 years old, suggesting it reached sexual maturity very late. A 2021 study estimated a 9.2-meter (30 ft) megalodon lived about 46 years and grew 16 cm (6.3 in) per year. Another study in 2022 suggested this individual may have been even larger.
Megalodon used warm, coastal nursery areas to give birth, such as in Panama, Maryland, and Florida. Baby megalodons were about 3.5 meters (11 ft) long and vulnerable to predators like great hammerhead sharks. Young megalodons ate fish, turtles, and small whales, while adults hunted large whales in open ocean areas.
One unusual fossil shows a juvenile megalodon may have attacked a large baleen whale. Tooth marks on a blue whale’s rib, which showed signs of healing, suggest the whale survived the attack.
Paleoecology
Megalodon was found in many parts of the world, with fossils discovered in Europe, Africa, the Americas, and Australia. It lived mostly in subtropical and temperate regions, with fossils found as far north as 55° N. Scientists believe it could survive in water temperatures between 1–24 °C (34–75 °F) because of mesothermy, a trait that allows large sharks to keep their body warmer than the surrounding water by retaining heat from their metabolism.
Megalodon lived in many types of ocean environments, such as shallow coastal areas, upwelling zones, swampy lagoons, sandy shorelines, and deep offshore waters. It had a mobile lifestyle, often moving between areas. Adult megalodon were rarely found in shallow waters, preferring deeper, offshore regions. They may have moved between coastal and open-ocean areas during different stages of their lives.
Fossil evidence shows that megalodon specimens in the Southern Hemisphere were, on average, larger than those in the Northern Hemisphere, with average lengths of 11.6 and 9.6 meters (38 and 31 ft), respectively. Similarly, fossils in the Pacific Ocean were larger than those in the Atlantic, averaging 10.9 and 9.5 meters (36 and 31 ft). No clear pattern of size changes with latitude or over time was found, though the Otodus lineage overall is thought to have grown larger over time. The most common size for megalodon was estimated at 10.5 meters (34 ft), with more fossils showing larger individuals, suggesting that bigger size may have been an advantage in their environment.
A study by Herraiz et al. (2026) found no significant differences in body size between Atlantic and Mediterranean megalodon populations, except for a known difference in fossils from the Miocene period in Spain.
Megalodon lived in all oceans during the Neogene period, with fossils found near every ocean.
Megalodon lived in a highly competitive environment and likely influenced the structure of marine ecosystems as a top predator. Fossils suggest a connection between megalodon and the rise of cetaceans and other marine mammals. Juvenile megalodon may have lived in areas with many small cetaceans, while adults lived where large cetaceans were common. These preferences may have developed after megalodon first appeared in the Oligocene.
Megalodon lived at the same time as large, whale-eating toothed whales, such as macroraptorial sperm whales and squalodontids, which were also top predators. Some of these whales, like Livyatan, grew as large as 13.5 to 17.5 meters (44 to 57 ft). Fossils from Lee Creek Mine in North Carolina suggest another species of these whales reached 8 to 10 meters (26 to 33 ft) and lived up to 25 years. This is much shorter than modern killer whales, which live up to 65 years, suggesting that these ancient whales were preyed on by larger predators like megalodon or Livyatan. Megalodon likely hunted macroraptorial sperm whales like Zygophyseter, indicating it may have occupied a higher position in the food chain than modern apex predators, as supported by calcium isotope analysis.
By the Late Miocene, about 11 million years ago, macroraptorial whales declined in number and variety, reducing competition. Earlier ideas that cetaceans increased competition during the Pliocene due to social, pack-hunting orcas are now questioned, as the oldest known orca species, Orcinus citoniensis, specialized in hunting small fish and squid rather than marine mammals.
Megalodon may have forced white sharks to avoid areas it inhabited, as fossils show other shark species lived in colder waters. In places like Pliocene Baja California, where their ranges overlapped, megalodon and great white sharks may have lived in the same area at different times of the year, following different prey. Megalodon likely hunted other sharks, similar to modern sharks.
Extinction
The Earth changed a lot during megalodon’s time, which affected ocean life. A cooling trend that started 35 million years ago led to glaciers forming at the poles. Geological events, like the closing of the Central American Seaway and changes in the Tethys Ocean, altered ocean currents and rainfall. These changes cooled the oceans. The slowing of the Gulf Stream stopped nutrient-rich water from reaching important marine areas, possibly harming megalodon’s food sources. The biggest sea level changes in the Cenozoic era happened during the Plio-Pleistocene, between 5 million and 12,000 years ago. This was caused by glaciers expanding at the poles, which hurt coastal environments and may have contributed to megalodon’s extinction along with other large marine animals. These ocean changes, especially falling sea levels, likely reduced shallow, warm-water nurseries where megalodon reproduced. Nurseries are important for shark survival because they protect young sharks from predators.
Megalodon lived in warmer waters and may not have been able to keep its body warm in colder areas. Fossils show megalodon was not found in places where water temperatures dropped during the Pliocene. However, studies of megalodon’s distribution over time suggest temperature changes did not directly cause its extinction. During the Miocene and Pliocene, megalodon lived in areas with temperatures from 12 to 27°C (54 to 81°F), with a total range of 1 to 33°C (34 to 91°F). This suggests temperature changes did not greatly affect its habitat, as it was a mesotherm, meaning it had a moderate body temperature.
Marine mammals were most diverse during the Miocene, with over 20 baleen whale species compared to only six today. This diversity created a good environment for a top predator like megalodon. By the end of the Miocene, many baleen whale species went extinct, leaving surviving species that may have been faster and harder to catch. After the Central American Seaway closed, tropical whales became less diverse and common. Megalodon’s extinction coincided with the decline of many small baleen whale species, suggesting it relied on them as food. A marine megafauna extinction during the Pliocene eliminated 36% of large marine species, including 55% of marine mammals, 35% of seabirds, 9% of sharks, and 43% of sea turtles. This extinction mainly affected endotherms and mesotherms, like megalodon, likely due to less food, which supports the idea that megalodon was mesothermic. The cooling oceans during the Pliocene may have limited megalodon’s access to polar regions, where large whales migrated.
Some scientists thought competition with large toothed whales, like sperm whales or Orcinus (Orcinus citoniensis), caused megalodon’s decline. However, evidence shows these whales appeared later in the Pliocene and may not have competed with megalodon. Giant sperm whales like Livyatan-like species disappeared around 5 million years ago, while smaller ones also vanished by that time. Some toothed whales, like Hoplocetus and Scaldicetus, survived longer into the Pliocene, but only Miocene species were large predators. Orcinus became large and predatory only in the Pleistocene, after megalodon was gone.
Paleontologist Robert Boessenecker and his team used a statistical model to estimate megalodon’s extinction date as about 3.51 million years ago. They suggest megalodon’s range shrank due to climate changes and competition with modern white sharks, not with large whales. Other studies also consider competition with white sharks as a possible factor, but more research is needed. Experts believe multiple factors, including climate change, limited food, and competition with white sharks, likely caused megalodon’s extinction. Some argue competition may have played a smaller role than other factors like habitat loss, cooling climates, and declining whale diversity.
Megalodon’s extinction changed marine ecosystems. After its disappearance, baleen whales grew larger, possibly due to climate changes. This size increase may have contributed to megalodon’s extinction, as it might have preferred smaller whales. Bite marks on large whales may have come from scavenging sharks. Megalodon may have gone extinct with smaller whales like Piscobalaena nana. Its extinction helped other top predators, like the great white shark, expand into areas where megalodon once lived.
In popular culture
Megalodon has appeared in many fictional stories, such as movies and books, and remains a common topic in tales about sea monsters. Reports of megalodon teeth that seemed to be very recent, like those found by HMS Challenger in 1873 and dated in 1959 by zoologist Wladimir Tschernezky to be 11,000 to 24,000 years old, helped some people believe that megalodons might still be alive. These claims were later proven false. Scientists think these teeth were preserved by a thick layer of manganese dioxide, which slowed their breakdown and kept them white during fossilization. Fossil megalodon teeth can range in color from off-white to dark browns, greys, and blues. Some teeth may have been moved to younger layers of rock after being buried. Claims that megalodons could live in deep ocean areas, like the megamouth shark discovered in 1976, are unlikely because megalodons lived in warm coastal waters and probably could not survive in cold, deep-sea environments. Reports of seeing megalodons are likely hoaxes or mistakes, such as confusing whale sharks with megalodons, as they share similar appearances.
Fictional stories about megalodons surviving today began with the 1997 book Meg: A Novel of Deep Terror by Steve Alten and its follow-up books. Megalodon later appeared in movies, such as Shark Attack 3: Megalodon (2002) and The Meg (2018), which was based on the 1997 book and earned over $500 million at the box office.
Animal Planet’s fake documentary Mermaids: The Body Found showed a scene from 1.6 million years ago where mermaids met a megalodon. In 2013, the Discovery Channel started its Shark Week series with a film called Megalodon: The Monster Shark Lives, a fictional program that claimed to show evidence of living megalodons. This program faced criticism for being entirely fictional and for not clearly stating that it was not real. For example, the scientists shown in the film were actors, and the documentary did not explain that it was not based on facts. A survey by Discovery found that 73% of viewers believed megalodons were not extinct. In 2014, Discovery re-aired The Monster Shark Lives along with two other fictional programs, causing more criticism from scientists and the media. Despite this, The Monster Shark Lives was very popular, with 4.8 million viewers, the most for any Shark Week episode at the time.
Megalodon is the official state shark of Maryland. Megalodon teeth are the state fossil of North Carolina.