The extinction of the megalodon, the largest shark that ever lived, is still a mystery, but there are several theories. Fossil evidence suggests that megalodons went extinct before about 2.6 million years ago, during a period of cooling and drying in many parts of the world. These changes may have been related to the closing of the seaways separating North from South America and Eurasia from Africa. The emergence of the Isthmus of Panama, for example, likely split populations of predators and prey alike and deflected ocean currents from their usual paths. The mix of environmental changes and rising walls of land almost certainly disrupted marine food chains, including those that supported baleen whales, which scientists believe were the main prey of megalodons. With white sharks and early killer whales also evolving to become formidable competitors with megalodons by that time, megalodons found fewer prey, and their populations crashed.

Another theory suggests that megalodon sharks became extinct in part due to climate change. As oceans grew colder, they may not have been able to regulate their body temperature, and many marine animals and fish could not survive the cold temperatures. As food supplies decreased, competition increased among large ocean predators, and some believe that predators such as the Livyatan could have fought in packs and killed megalodon sharks.

One recent theory suggested that megalodon died off during a mass extinction event caused by a supernova 150 light-years away that irradiated and heated our planet 2.6 million years ago. Research indicated that the radiation would have penetrated into the deep seas and persisted for years, killing animals en masse. However, paleontologists estimate that megalodon went extinct as much as a million years before the supernova. A new study published in Nature Communications supports the theory that one culprit lending to megalodon’s extinction was the great white shark, whose ancestors plied the seas in parallel with the megatooth sharks. The study suggests that one of multiple causes of megalodon’s extinction may have been competition over food, as deduced from analyzing zinc isotopes in the enamel of fossil shark teeth as an indication of diet. The changing climate and environmental pressures, such as sea level changes, also played a role.

In conclusion, the extinction of the megalodon was likely due to a complex mix of challenges, including climate change, competition over food, and environmental pressures.