Long before great white sharks appeared, much larger ancestors roamed the ocean. This giant ancient shark -- the Giant Megatooth (Carcharodon megalodon) -- was probably big enough to eat a whale.
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Shark Ancestors
Giant Megatooth Model
Credit: © François Gohier/San Diego Natural History MuseumA life-sized model suspended over visitors at the San Diego Natural History Museum shows what an ancient shark, the Giant Megatooth (Carcharodon megalodon), might have looked like.
More about the great white shark can be found in our Great White Shark featured story
Megalodon Teeth
Credit: © Lollo Enstad/San Diego Natural History MuseumTwo fossilized teeth from a megalodon (Carcharodon megalodon) dating back more than 20 million years. Their teeth can reach a diagonal length of seven inches! The ancestry of great white sharks has long been debated, but by looking closer at shark teeth scientists know that the giant megatooth shark was not an ancestor of the great white shark. More about the great white shark can be found in our Great White Shark featured story.
How Big are Great White Sharks?
Credit: © Mary Parrish/Smithsonian InstitutionImagine an adult person – now triple that size. That’s the size of the great white shark (Carcharodon carcharias). The biggest great white sharks can reach up to 20 feet long, but most are smaller. The average female is 15-16 feet long, while males reach 11-13 feet. More about the great white shark can be found in our great white shark overview.
Take the size of an adult person and multiply it ten times, and you get the Giant Megatooth (Carcharocles megalodon) about the size and weight of a railroad car.
Fossil tooth spiral
Credit: © Chip Clark/Smithsonian InstitutionThis fossil tooth whorl of the ancient shark Helicoprion, dates back 290 million years. For a long time, people didn't know what the shark looked like—but, thanks to a CT scan of a fossil, researchers finally put the pieces together in 2013. Read more about this story in our great white shark overview, and learn more about top predators like Helicoprion in the Ocean Over Time section.
Illustration of Helicoprion
Credit: © Mary Parrish/Smithsonian InstitutionThis illustration shows one old idea of what the ancient shark Helicoprion might have looked like. There once was room for many ideas—some more plausible than others—because the only fossils of the fish were of a strange, spiral-shaped jaw loaded with teeth. Where did the spiral jaw go? In its mouth, on its nose, or its head? A study published in 2013 finally cleared up the mystery: the spiral is completely embedded in the shark's lower jaw and serves as it's full toothset, unlike the sharks drawn here, which have full jaws in addition to the toothy whorl. Read more about this finding in our great white shark featured story.