For Real, Did Megalodon Go Extinct?

Why and how did these impressive creatures disappear from the Earth

As some of you know, I was privileged to work and do science at the Paleobiology Department at the National Museum of Natural History Smithsonian Institution for many years. As you can imagine, that was one of the most transformative years of my life.

I was surrounded by groundbreaking fossil discoveries every day of my life. I could see new theories and ideas being generated right before my eyes, it was magical. And of course, friends and family were always eager to ask questions.

I was working on some analytical processes when I got a text from my sister and her children: What do you think of Megalodon?

I needed clarification. What do you mean by “think”?

She said they had just watched a documentary claiming that Megalodon still existed and was still roaming the oceans.

I almost choked. Really? My own sister was the victim of the misinformation media. I clearly did something wrong and failed to educate her on critical scientific thinking.

However, after reading about why people were misinformed on the topic, I quickly understood that it wasn’t entirely her fault. They really created a pseudo-documentary on the topic. I needed to provide her with facts and maybe help my readers with the question, too.

Megalodon is the largest shark ever known. At up to 18 meters long, it was an apex predator that dominated the oceans for millions of years. However, around 2.6 million years ago, it vanished from the fossil record, marking the end of its reign.

And yes, the scientific evidence shows that Megalodon is definitely extinct, Despite Hollywood’s portrayal of these sharks surviving into modern times. So, what caused the demise of this apex predator, and when exactly did it happen?

In 2016, Dr. Catalina Pimiento and her team set out to test one of the common theories about Megalodon’s extinction. For a long time, scientists believed that Megalodon disappeared due to the onset of the Ice Ages, when cooler water temperatures made life difficult for the giant shark or because its prey — the whales — migrated to colder regions.

To test this, Pimiento’s team used climate modeling and fossil analysis to compare ancient ocean temperatures with where Megalodon remains have been found.

The research team used climate forecasting models to recreate ocean temperatures during the Pliocene and Miocene epochs, the periods when Megalodon lived. They then compared these temperatures to the locations where Megalodon fossils were discovered to see if the sharks avoided colder waters.

By assessing the water temperature ranges that would have supported Megalodon’s survival, the team could evaluate whether cold water played a role in its extinction. Simple but neat.

What the researchers found surprised many: Megalodon was not strictly a warm-water shark.

While it preferred water temperatures between 12 and 27 degrees Celsius, fossils have been found in regions where the water was as cold as 1 degree Celsius.

This indicates that Megalodon, like many modern sharks, had the ability to survive in a wide range of temperatures, possibly due to a mesothermic physiology. This feature allows large sharks to keep their bodies warmer than the surrounding water, which would have helped Megalodon thrive in colder environments.

I know, how cool is that? However, if the cold wasn’t the main reason for its extinction, what was then?

Dr. Pimiento et al. suggest that Megalodon’s real problems were competition and a changing food supply.

Let me explain. Around the time of its extinction, the structure of marine life began to shift. Large predatory whales, such as Livyatan melville, appeared on the scene, hunting the same prey that Megalodon relied on—marine mammals like whales and seals.

Along with these new competitors, the ancestors of today’s Great White Sharks also emerged and began to compete with Megalodon for food.

At the same time, the number of whale species started to decline due to changes in ocean circulation and food availability. Filter-feeding whales, which were crucial prey for Megalodon, became less abundant, leading to increased competition for what was left. With fewer food sources and more agile predators like the Great White Shark thriving, Megalodon simply couldn’t keep up.

Thus, Megalodon’s extinction likely came about due to a combination of factors — cooler water temperatures, changes in its food supply, and competition from emerging predators. The shark, once dominant in the oceans, found itself in an environment that no longer favored its enormous size and high energy needs. The arrival of faster, more efficient hunters, along with the drop in available prey, meant that Megalodon could no longer maintain its status at the top of the food chain.

However, this wasn’t an isolated event with no consequences; this extinction event left a significant impact on the ocean ecosystem. With Megalodon gone, whale species were able to grow larger, eventually leading to the massive blue whales we see today.

In a way, the decline of the world’s largest shark allowed the rise of the largest animals to ever exist. Thanks, Megalodon!

Although the idea of a supersized shark patrolling the seas is exciting, the evidence clearly shows that Megalodon has been extinct for over two million years. Further, its disappearance reminds us how fragile ecosystems can be, even for the biggest and most powerful predators.

So, next time someone asks, show them this story. And if you’d like something more visual, make sure to check out this PBS Eons episode covering this topic.

Stay curious!