Researchers Confirm That The Megalodon Died Out Over Two Million Years Ago

Chuck Bednar for redOrbit.com – Your Universe Online
An ancient 45- to 60-foot shark that resembled a larger version of the Great White shark, became extinct over two million years ago, and its death may have caused whales to grow to their current sizes, research published last week in the journal PLOS ONE claims.
In the study, researchers from the University of Florida and the University of Zurich set out to dismiss claims that Carcharocles megalodon (megalodon), the largest shark that ever existed, was still alive. They reviewed the most recent records of the megalodon from literature and scientific collections, and through a novel use of the Optimal Linear Estimation (OLE) model, determined that the massive predator died out 2.6 million years ago.
In a statement, lead author Catalina Pimiento, a doctoral candidate at the Florida Museum of Natural History on the UF campus, said that she was drawn to the subject because “it is fundamental to know when species became extinct to then begin to understand the causes and consequences of such an event.”
“I also think people who are interested in this animal deserve to know what the scientific evidence shows, especially following Discovery Channel specials that implied megalodon may still be alive,” she added. The research represents the first phase of Pimiento’s ongoing reconstruction of megalodon’s extinction – research that she believes will lead to a better understanding of the consequences that could result if current predators suffer the same fate.
Modern predators, especially large sharks, are currently experiencing significant global population declines due to the ongoing biodiversity crisis, the university explained. Recent estimations indicate that large, shallow-water sharks are at the greatest risk among all types of marine animals, and if they die out, smaller sharks become more abundant and wind up consuming more of the invertebrates typically consumed by humans.
The situation may have been similar 2.6 million years ago. It was around this time, between the Pliocene and Pleistocene epochs, that baleen whales began to grow to their current, gigantic sizes, explained BBC News online science editor Paul Rincon. While there is no conclusive evidence that megalodons fed on baleen whales, the fossils of both species are often found together, and the removal of the predator might have allowed the prey to flourish and grow larger than ever before.
“When we calculated the time of megalodon’s extinction, we noticed that the modern function and gigantic sizes of filter feeder whales became established around that time,” Pimiento explained. “Future research will investigate if megalodon’s extinction played a part in the evolution of these new classes of whales.”
“When we found out when that happened, we noticed it coincided with the pattern mentioned in whales. Now we need to find out if one event – megalodon’s extinction – caused the other – evolution of gigantism in whales,” she told BBC News. “From modern sharks, it is known that larger individuals have a broader range of prey size, including larger prey. That means that the larger prey will be predated mostly by larger sharks.”
Pimiento and her University of Zurich colleague Dr. Christopher Clements used OLE on 42 of the most recently discovered fossils of the gargantuan shark. OLE, Rincon explained, is a mathematical technique used to assess the spacing between fossil dates. It allows researchers to come up with a statistical inference of the date at which the species could be considered extinct – in this case, that point was 2.6 million years ago.
“It’s not exact, not least because there is a margin of error on the dates of the last fossils themselves. But it represents a refinement on previous estimates of the extinction date for this fearsome species,” the BBC reporter added. “The cause of Megalodon’s disappearance, however, remains a mystery.”
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