The Oldest Megalodon Fossil Shows the Ocean’s Old Pecking Order

Written by Kristen Holder
Published: February 6, 2023
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Megalodons (Otodus megalodon) are one of the most famous ancient sea creatures because of their enormous size and ferocity. The oldest megalodon fossils show the ocean’s old pecking order because they allow us to ascertain a lot about this ancient giant without much evidence. 

What is a Megalodon?

Megalodons are huge extinct sharks that occupied the earth’s oceans millions of years ago. They are the largest sharks ever though this determination is based solely on the size of their teeth.

Since sharks are made of cartilage, the rest of the megalodon’s body has never been directly studied. This means that no one is sure what megalodon looked like though guesses are made based on the bodily structure of extant sharks.

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They were up to 60 feet long and weighed over 100,000 pounds. This means the megalodon was as big as a bus and weighed as much as a train car. It had a bite force of 40,000 pounds and a mouthful of teeth up to 7 inches long.

It used to be commonly believed that the megalodon was closely related to the great white shark. This turned out to be wrong as the megalodon and great white diverged over 100 million years ago.

Megalodon Shark Hunting some Dolphins.

Megalodon bodies measured up to 60 feet long!

©Antonio Viesa/

What is the Oldest Megalodon Fossil?

The oldest megalodon fossils are fossilized teeth from around 20 million years ago during the Miocene Epoch. A child in England found a megalodon tooth on a beach and it is the oldest one ever found. Megalodon teeth are not uncommon and many are for sale online for as little as 20 dollars.

Not much of a megalodon’s body appears in the fossil record as sharks are made of cartilage. However, their teeth and backbones do survive. There are only a few vertebrae in existence so almost all of our information about megalodons comes from their teeth.

Fossil records show that the megalodon played a large part in keeping the population growth of certain species in check. There are whale bones from the right period that show megalodon teeth marks.

Whale bones are also commonly fossilized with megalodon teeth. There are also instances of fossilized whale bones with embedded megalodon teeth still in them.

Scientists know that megalodons went extinct about 3.6 million years ago because their teeth completely disappear from the fossil record after that point. Megalodon teeth are a ubiquitous occurrence on the planet due to their wide range. Their absence after a specific point in time suggests that they were already completely gone.

Megalodon and the Ocean’s Old Pecking Order

It’s believed megalodons made regular meals out of other large predators. It ate things like humpback whales and dolphins with impunity. Their mouths sometimes were 11 feet wide to accommodate these large food choices though they had no problem tearing a carcass apart.

Because megalodon was fast, ferocious, and huge, it ate a huge variety of ocean animals. This shark relied heavily on marine mammals because they’re a calorie-dense food choice compared to smaller fish species.

Megalodon was an apex predator at the highest trophic level which means it was at the top of the food chain. No animals used megalodon reliably as a food source. Megalodon was able to eat such large animals that it existed in a place above anything on earth today concerning its place in the food chain.

When an herbivore eats plants, it transforms plant material into what is needed for its biology. This makes them nutritious to carnivorous animals designed to digest their plant-driven bodies.

From there, some carnivores are prey to bigger carnivores. Megalodon was so huge that it ate carnivores so large that there’s no equivalent on the planet today by two levels. Its teeth were serrated so it could quickly slice through and swallow enormous amounts of meat.

As the world started cooling more than 3.6 million years ago, ocean temperatures and levels dropped which caused an animal die-off. Animals that relied on other animals for food died at a higher rate due to a drop in prey. 35 percent of sea birds and 43 percent of sea turtles went extinct along with megalodon.

Megalodon tooth

Comparison of fossilized Megalodon (left) and Great White Shark teeth.


When Did Megalodon Go Extinct?

Megalodon went extinct around 3.6 million years ago right before the switch from the Pliocene into the Pleistocene Epoch. They evolved into existence around 23 million years ago. It had a large range and evidence of these monsters exists in Africa, Europe, and the Americas.

In the late Miocene over 5 million years ago, megalodon populations became smaller. As temperatures on earth dropped, the tropical and subtropical waters that were home to this shark became much smaller. Populations of megalodons then fractured and experienced restricted ranges before dying out.

This fracturing may also have been influenced by dropping sea levels. As water levels lowered, the land bridge between North America and South America separated the Pacific Ocean from the Caribbean. This may have affected the megalodon so drastically that it helped drive them to extinction.

What Happened When Megalodon Disappeared?

A few million years ago, whales that relied on filter feeding dropped in number in response to cooling temperatures. As their numbers dropped, smaller carnivorous animals blossomed. This changed the biodiversity of the ocean in dramatic ways.

While great white sharks are formidable animals, they’re about one-third of a megalodon’s size. Animals like great white sharks and orcas are ferocious and opportunistic hunters that are more stealthy than megalodons due to their smaller size.

These mid-sized predatory animals are adept hunters and they outcompeted megalodons for shared prey. A lack of prey abundance combined with climate change most likely drove megalodon to extinction.

When the megalodon went extinct over 3 million years ago, animals that were preyed on were affected. For example, since the remaining baleen whales were not eaten, their populations boomed. Right after the megalodon’s extinction, the fossil record shows that baleen whales began growing in size when their population expanded.

This unchecked growth trended toward gigantism in response to this shift in power and the environment on the planet at the time. This paved the way for the development of animals like the blue whales of today.

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The photo featured at the top of this post is © racksuz/

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About the Author

Kristen Holder is a writer at A-Z Animals primarily covering topics related to history, travel, pets, and obscure scientific issues. Kristen has been writing professionally for 3 years, and she holds a Bachelor's Degree from the University of California, Riverside, which she obtained in 2009. After living in California, Washington, and Arizona, she is now a permanent resident of Iowa. Kristen loves to dote on her 3 cats, and she spends her free time coming up with adventures that allow her to explore her new home.

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