麻豆影视

Skip to main content

Study challenges claim early human hunters killed off prehistoric elephants

Visitors walk past a Mastodon skeleton display at the opening of the Royal Alberta Museum, in Edmonton on Wednesday, Oct. 3, 2018. (THE CANADIAN PRESS/Jason Franson) Visitors walk past a Mastodon skeleton display at the opening of the Royal Alberta Museum, in Edmonton on Wednesday, Oct. 3, 2018. (THE CANADIAN PRESS/Jason Franson)
Share
TORONTO -

A new study suggests that prehistoric elephants like the mastodon and woolly mammoth were wiped out by waves of extreme global environmental change, rather than being hunted to extinction by early humans.

The study, entitled 鈥淭he rise and fall of proboscidean ecological diversity,鈥 published Thursday in Nature Ecology & Evolution, challenges the claim that early human hunters hunted prehistoric elephants to extinction over millennia. Instead, it presents findings that the extinction of the last mammoths and mastodons at the end of the last Ice Age marked the end of climate-driven global decline among elephant species over millions of years.

An international group of paleontologists from the Universities of Alcala in Spain, Bristol in the U.K., and Helsinki, Finland, ran the study to analyse the rise and fall of elephants and their predecessors over 60 million years of evolution, according to a release.

The study explains that while today elephants are categorized into three endangered species in the African and Asian tropics, their ancestors were a group of giant herbivores known as the proboscideans, which include the extinct mastodons, stegodons and deinotheres.

By studying the fossil collections in museums across the globe, like London鈥檚 Natural History Museum to Moscow鈥檚 Paleontological institute, the research team logged and analyzed traits like body size, skull shape and teeth, and found that proboscideans fell within one of eight sets of adaptive evolutionary strategies.

鈥淩emarkably for 30 million years, the entire first half of proboscidean evolution, only two of the eight groups evolved,鈥 said study co-author Dr. Zhang Hanwen in the release. 鈥淢ost proboscideans over this time were nondescript herbivores ranging from the size of a pug to that of a boar. A few species got as big as a hippo, yet these lineages were evolutionary dead-ends. They all bore little resemblance to elephants.鈥

However, the evolution of ancient elephant species changed dramatically when a migration corridor opened up through the Bering Land Bridge after the Afro-Arabian plate collided into the Eurasion continent approximately 20 million years ago.

鈥淭he immediate impact of proboscidean dispersals [migration] beyond Africa was quantified for the very first time in our study,鈥 lead study author Dr. Juan Cantalapiedra said in the release.

Access to a new continent meant new evolutionary processes to adapt to new environments.

鈥淭he aim of the game in this boom period of proboscidean evolution was 鈥榓dapt or die.鈥 Habitat perturbations were relentless, pertained to the ever-changing global climate, continuously promoting new adaptive solutions while proboscideans that didn鈥檛 keep up were literally, left for dead,鈥 Zhang explains in the release.

The researchers found that by three million years ago, environmental disruptions from the coming Ice Ages hit the proboscideans hard, resulting in evolutionary tactics in species like the woolly mammoth, which had shaggy hair and big tusks for retrieving vegetation covered under thick snow, the study says.

By analyzing the extinction peaks, or periods of time the ancient species would be 鈥渟ubject to higher extinction risk,鈥 of the proboscideans at 2.4 million years ago, 160,000 and 75,000 years ago in Africa, Eurasia and the Americas, the team discovered that the results did not correlate with the expansion of early humans and their 鈥渆nhanced capabilities to hunt down megaherbivores.鈥

The results surprised researchers.

鈥淲e didn鈥檛 foresee this result. It appears as if the broad global pattern of proboscidean extinctions in recent geological history could be reproduced without accounting for impacts of early human diasporas,鈥 said Zhang, adding that the study 鈥渞efutes some recent claims regarding the role of archaic humans in wiping out prehistoric elephants, ever since big game hunting became a crucial part of our ancestors鈥 subsistence strategy around 1.5 million years ago.鈥 

CTVNews.ca Top Stories

The British Columbia election campaign is set to officially start today, with Lt.-Gov. Janet Austin issuing the writ for the Oct. 19 vote.

A northern Ontario man is facing a $12,000 fine after illegally shooting a moose near the Batchawan River.

Unusual flippered feet are making their way into the Saint Lawrence River this weekend. Led by underwater explorer and filmmaker Nathalie Lasselin, volunteer divers are combing the riverbed near Beauharnois in Mont茅r茅gie to remove hundreds of tires that have been polluting the aquatic environment for decades.

A sea lion swam free after a rescue team disentangled it near Vancouver Island earlier this week.

Local Spotlight

Cole Haas is more than just an avid fan of the F.W. Johnson Wildcats football team. He's a fixture on the sidelines, a source of encouragement, and a beloved member of the team.

Getting a photograph of a rainbow? Common. Getting a photo of a lightning strike? Rare. Getting a photo of both at the same time? Extremely rare, but it happened to a Manitoba photographer this week.

An anonymous business owner paid off the mortgage for a New Brunswick not-for-profit.

They say a dog is a man鈥檚 best friend. In the case of Darren Cropper, from Bonfield, Ont., his three-year-old Siberian husky and golden retriever mix named Bear literally saved his life.

A growing group of brides and wedding photographers from across the province say they have been taken for tens of thousands of dollars by a Barrie, Ont. wedding photographer.

Paleontologists from the Royal B.C. Museum have uncovered "a trove of extraordinary fossils" high in the mountains of northern B.C., the museum announced Thursday.

The search for a missing ancient 28-year-old chocolate donkey ended with a tragic discovery Wednesday.

The Royal Canadian Mounted Police is celebrating an important milestone in the organization's history: 50 years since the first women joined the force.

It's been a whirlwind of joyful events for a northern Ontario couple who just welcomed a baby into their family and won the $70 million Lotto Max jackpot last month.