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Competition may have killed off largest shark ever

April 2, 2016
Courtesy of the University of Zurich
and World Science staff

Is there an­y­one who does­n’t know Jaws, the film about the great white shark and the dev­asta­t­ion it wreaked? But there have been big­ger and more dan­ger­ous sharks in the past. 

The larg­est known shark species ev­er, Car­charo­cles mega­lodon, reached lengths up to 18 me­ters (59 feet). That’s the length of a vol­ley­ball court, or about three times that of a typ­i­cal adult great white. (The fic­tion­al “Jaws” was por­trayed as 25 feet long).

A C. megalodon jaw aw the Flo­r­ida Mus­eum of Na­tur­al His­tory. (©Jeff Gage / Fla. Mu­seum of Na­tur­al His­tory)


But the an­cient beast, thought to have fed on ma­rine mam­mals dur­ing its ter­ri­fy­ing ex­ist­ence be­tween 23 mil­lion and 2.6 mil­lion years ago, died out. 

Sci­en­tists have blamed cli­mate changes for the dis­ap­pear­ance, but a new study con­cludes that the shark per­ished be­cause the di­vers­ity of its prey shrank and new com­peti­tors ap­peared.

The re­search­ers, Catalina Pi­mien­to from the Pa­le­on­to­lo­gic­al In­sti­tute and Mu­se­um of the Un­ivers­ity of Zu­rich in Switz­er­land and col­leagues, ex­am­ined the an­i­mal’s geo­graph­i­cal range and abun­dance over time. 

To do that they as­sessed roughly 200 me­ga­lodon records from mu­se­um col­lec­tions and databases, rang­ing in age over more than 20 mil­lion years.

Their find­ings: early in the so-called Mi­o­cene ep­och—which lasted from about 23 mil­lion to 5 mil­lion years ago—the sharks were mainly found in the North­ern Hem­i­sphere in the warm wa­ters off the coast of Amer­i­ca, around Eu­rope and in the In­di­an Ocean. They lat­er pen­e­trated fur­ther in­to the Asian, Aus­tral­ian and South Amer­i­can coasts. Spe­cies abun­dance peak­ed in the mid­dle Mi­o­cene, but its great­est range was in the late Mi­o­cene. 

A con­tin­u­ous de­cline fol­lowed around 5 mil­lion years ago. Al­though a gla­cial pe­ri­od emerged grad­u­ally at this time, the so-called Pli­o­cene ep­och, the re­search­ers said they could­n’t as­cer­tain any link be­tween the cold and the ex­tinc­tion. In fact cold and warm spells “do not ap­pear to have had any in­flu­ence on [the shark’s] popula­t­ion dens­ity and range,” said Pi­mien­to.

In­stead, she said, its fate seems to have been in­ter­twined with oth­er spe­cies. When mega­lodon range shrank, many smaller ma­rine mam­mal spe­cies disap­peared and new preda­tors ap­peared such as the an­ces­tors of the kill­er whale and the great white shark. The re­sults sug­gest these spe­cies could have com­pet­ed for in­creas­ingly scarce food, the re­search­ers said.

The find­ings are pub­lished in The Jour­nal of Bi­o­ge­og­raphy.


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Is there anyone out there who doesn’t know Jaws, the film about the great white shark and the devastation it wreaked? But there have been bigger and more dangerous sharks in the past. The largest known shark ever, Carcharocles megalodon, reached lengths up to 18 meters (59 feet). That’s the length of a volleyball court, or about three times that of a typical adult great white (the fictional “Jaws” was portrayed as 25 feet long). But the ancient beast, thought to have fed on marine mammals during its terrifying existence between 23 million and 2.6 million years ago, died out. Scientists have blamed climate changes for its disappearance, but a new study said the shark perished because the diversity of its prey shrank and new competitors appeared. The researchers, Catalina Pimiento from the Paleontological Institute and Museum of the University of Zurich in Switzerland and colleagues, examined the animal’s geographical range and abundance over time. To do that they assessed roughly 200 megalodon records from museum collections and databases, ranging in age over more than 20 million years. Their findings: early in the so-called Miocene epoch—which lasted from about 23 million to 5 million years ago—the sharks were mainly found in the Northern Hemisphere in the warm waters off the coast of America, around Europe and in the Indian Ocean. They later penetrated further into the Asian, Australian and South American coasts. Species abundance peaked in the middle Miocene, but its greatest range was in the late Miocene. A continuous decline followed around 5 million years ago. Although a glacial period emerged gradually at this time, the so-called Pliocene epoch, the researchers said they couldn’t ascertain any link between the cold and the extinction. In fact cold and warm spells “do not appear to have had any influence on [the shark’s] population density and range,” said Pimiento. Instead, she said, its fate seems to have been intertwined with other species. When Megalodon range shrank, many smaller marine mammal species disappeared and new predators appeared such as the ancestors of the killer whale and the great white shark. The results suggest these species could have competed for the increasingly scarce food sources, the researchers said. The findings are published in the Journal of Biogeography.