Megalodon | Size, Fossil, Teeth, & Facts - Encyclopedia Britannica

Physical features

Megalodon was the largest fish ever known, a designation based on discoveries of hundreds of fossil teeth, two vertebral columns, and a handful of individual vertebrae. Tooth-shape similarities between megalodon and modern great white sharks (Carcharodon carcharias) suggest that the two species may have been close relatives, and thus megalodon likely resembled that species in appearance—that is, as a bulky torpedo-shaped fish with a conical snout, large pectoral and dorsal fins, and a strong crescent-shaped tail. Estimates of body length are calculated using the statistical relationship between the size of megalodon’s fossil teeth and the teeth and body mass of modern white sharks and other living relatives. This data suggests that mature adult megalodons had a mean length of between 13 and 14 metres (about 42.7 and 45.9 feet), with the largest specimens measuring up to an estimated 24.3 metres (79.7 feet) long. Studies estimate that adult body mass ranged from roughly 30 metric tons (1 metric ton = 1,000 kg; about 66,000 pounds) to more than 65 metric tons (about 143,000 pounds), adult females being larger (in both length and mass) than adult males.

However, some scientists note that Megalodon may have possessed a sleeker body, possibly with a shape closer to that of a lemon shark. They argue that a large, bulky shark with the proportions described above may have had more difficulty moving through the water than a shark with more slender body shape. Size estimates suggest that such a sleek-bodied form was larger than previously thought, possibly measuring as much as 24.3 meters (about 80 feet) long and weighing about 94 tonnes (103 tons).

Megalodon teeth are similar to those of modern white sharks in that they are triangular, serrated, and symmetrical. They differ from modern white shark teeth in that they are larger and thicker, the serrations on each tooth occur in regular intervals, and they possess a bourlette (a darker, chevron-shaped region near the tooth’s root). The largest extant megalodon tooth measures 17.8 cm (6.9 inches) in length, almost three times longer than those of modern white sharks (which are typically about 5.4 cm [2.1 inches] long). In addition, megalodon possessed a ferocious bite; its bite diameter was 3 metres (about 9.8 feet), several times larger than the bite diameter of averaged-sized white sharks.

Britannica Quiz Understanding Megalodon

Megalodon is thought to have managed its body temperature in a manner similar to that of modern white sharks, in that it was not exclusively cold-blooded like most fish. White sharks generate heat through the contraction of their swimming muscles, and this heat raises the temperature of parts of the shark’s body above that of the surrounding water, an adaptation called regional endothermy (which is a type of warm-bloodedness). This adaptation might have allowed megalodon to swim and hunt in colder waters, giving it exclusive access to prey in those locations.

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