4 weeks ago
A new paper in the Journal of Life and Environmental Sciences reveals the likely cause for the megalodon shark’s extinction, CNN reports.
Competition from a fish much smaller, but sill quite deadly in its own right, caused the demise for the biggest shark species ever. That fish? The great white shark.
Previous theories about the cause of the megalodon’s disappearance included a supernova leading to radiation poisoning in large animals, or a mass dying out of seals or other food for the mega shark. Robert Boessenecker, a vertebrate paleontologist with the College of Charleston in South Carolina analysed data that led to a new theory that great white sharks are actually to blame.
“We used the same worldwide dataset as earlier researchers but thoroughly vetted every fossil occurrence, and found that most of the dates had several problems.”Boessenecker said. “Fossils with dates too young or imprecise, fossils that have been misidentified, or old dates that have since been refined by improvements in geology,” he explained.
His team used the densely sampled rock record of both California and parts of Mexico to determine that the fossil record of the megalodon stops appearing 3.6 million years ago, not the previously thought point of 2.6 millions years ago.
Around that former time period, the rise of another apex predator, the great white shark, was taking place across the globe’s oceans. With greater numbers of great whites came increased competition for the same prey that fed the megalodon shark.
“We propose that this short overlap (3.6-4 million years ago) was sufficient time for great white sharks to spread worldwide and out-compete (the) megalodon throughout its range, driving it to extinction,” Boessenecker said.
Emma Bernard, a curator of fossil fish at London’s Natural History Museum is excited about the new evidence: “The cause of this extinction is still hotly debated, but a broad consensus is that competition with other large apex predators such as killer whales and the great white shark could be an important factor,” she told CNN via email.Read the full story at CNN