A team of international researchers from Italy, Belgium, and Peru has uncovered new evidence that sheds light on one of the ocean’s greatest mysteries: the extinction of the giant prehistoric shark known as megalodon. This massive predator, whose scientific name is Otodus megalodon, once dominated the oceans from approximately 17 million to 2.6 million years ago. Some individuals of this ancient species are estimated to have reached over 50 feet in length—roughly three times the size of today’s largest great white sharks—and had a bite force powerful enough to crush a car. But despite its immense size and strength, megalodon eventually vanished from the seas. Scientists have long debated why such an apex predator would disappear, and now, new fossil evidence from Peru offers a compelling explanation that ties megalodon’s fate to the effects of climate change and the extinction of its prey.
The team’s findings, recently published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, are the result of careful fieldwork in southern Peru. There, the researchers discovered 7-million-year-old marine mammal fossils, including bones from a dwarf baleen whale species and an ancient relative of modern seals. These marine animals were relatively small, measuring up to 5 meters (about 16 feet) in length. But the most significant clue was the distinctive bite marks found on these fossils—evidence that they had been attacked, likely by none other than megalodon itself.
According to the researchers, these bite marks represent the first direct evidence of megalodon preying on small whales in this region. Until now, much of what scientists believed about megalodon’s diet was speculative, based on the size and structure of its enormous teeth and the fossilized remains of other marine animals found in its presumed habitats. This new discovery reinforces the theory that small baleen whales made up a substantial part of megalodon’s diet, and it provides insight into the complex food web of the late Miocene oceans.
But why would megalodon’s reliance on these smaller prey species lead to its downfall? The answer, according to the study, lies in the dramatic climate changes that occurred during the late Miocene and early Pliocene epochs. As the Earth’s climate cooled, polar ice caps expanded, sea levels dropped, and ocean currents shifted. These environmental changes had a profound impact on marine life. Smaller baleen whales, like the ones found in Peru, likely struggled to adapt. Unlike their larger relatives, which evolved the ability to migrate over vast distances in search of food, these smaller whales couldn’t travel far enough to reach newly located feeding grounds in colder, less hospitable waters. As a result, many of these species went extinct.
With their primary prey vanishing, megalodon may have faced a severe food shortage. Unlike more adaptable marine predators, megalodon itself may not have been capable of making the same long migrations to find alternative prey. Its massive size, while advantageous in terms of hunting power, likely came with high metabolic demands, meaning it needed to consume large amounts of food regularly to survive. As its preferred food sources dwindled, megalodon would have struggled to sustain itself.
This discovery adds a significant piece to the puzzle of megalodon’s extinction, but the researchers are careful to point out that it may not tell the entire story. Other studies have suggested that competition with emerging predators played a role as well. For example, around the time megalodon was declining, great white sharks (Carcharodon carcharias) and early species of killer whales (Orcinus orca) were becoming more dominant in the oceans. Both species were highly efficient predators that may have competed with megalodon for food. In addition, great white sharks, in particular, were better suited to colder water conditions and could survive on a more varied diet. This adaptability may have given them an advantage as climate change reshaped the ocean ecosystems.
The idea that climate-driven changes in prey availability contributed to megalodon’s extinction highlights an important concept in ecology: even the most fearsome predators are vulnerable if their environment shifts in ways that disrupt their food sources. It’s a sobering reminder that apex predators, no matter how powerful, are deeply interconnected with the health of the entire ecosystem.
Megalodon’s extinction also has broader implications for understanding the dynamics of marine ecosystems during times of environmental upheaval. The late Miocene and early Pliocene epochs were periods of significant climate transformation, with profound effects on ocean circulation, temperature, and productivity. These changes not only wiped out entire species of marine mammals but also triggered the evolutionary radiation of others, including modern whales, seals, and dolphins. As the oceanic environment cooled and became less favorable for the small, coastal baleen whales that megalodon preyed upon, new species of larger, migratory whales began to thrive, exploiting food sources in distant polar regions.
The fossil evidence from Peru adds valuable detail to this evolutionary narrative. The dwarf baleen whales found there would have occupied coastal environments, feeding on rich supplies of plankton and small fish in warmer waters. As these habitats disappeared due to dropping sea levels and cooling oceans, the whales’ populations likely crashed. Megalodon, in turn, lost a crucial link in its food chain. The disappearance of one species can ripple through an ecosystem in unexpected ways, and in this case, it may have contributed to the collapse of one of the ocean’s greatest predators.
Interestingly, this case mirrors the challenges faced by modern marine ecosystems, where climate change, overfishing, and pollution are altering food webs and threatening top predators. Scientists today study ancient extinction events like megalodon’s not only to solve paleontological mysteries but also to better understand how environmental changes can disrupt complex ecological relationships.
While the Peruvian fossils provide compelling new evidence about megalodon’s extinction, there are still many unanswered questions. For instance, did megalodon populations in other parts of the world suffer the same fate? Were there regional differences in diet or migratory patterns that influenced how various populations responded to climate change? And what role did genetic factors play in megalodon’s decline—was the species already suffering from low genetic diversity or other vulnerabilities that made it less resilient to environmental stress?
As researchers continue to uncover and study fossil evidence from around the world, new answers may emerge. For now, the picture that is coming into focus suggests that climate change, prey extinction, and competition with other predators likely formed a perfect storm that spelled the end for megalodon.
Despite its extinction, megalodon continues to fascinate scientists and the public alike. Its teeth—some measuring over seven inches in length—remain among the most iconic fossils ever discovered. These massive relics remind us of an ancient time when Earth’s oceans were ruled by a predator unlike any other. And thanks to new discoveries like those in Peru, we are gradually piecing together the story of how even the largest and most fearsome creatures are not immune to the forces of environmental change.
In the end, megalodon’s story is not just a tale of a single species but a window into the dynamic and interconnected history of life on Earth. Its rise and fall tell us much about the power of evolution, the impact of climate, and the delicate balance that sustains life in the oceans. As we grapple with modern-day challenges to marine biodiversity, the lessons of megalodon’s extinction offer both warnings and insights into how ecosystems respond to change—and how easily even the mightiest creatures can be swept away when those changes come too fast.
More information: Alberto Collareta et al, Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru, Palaeogeography, Palaeoclimatology, Palaeoecology (2017). DOI: 10.1016/j.palaeo.2017.01.001