Mammoths Survived in Canada Until 5,000 Years Ago

Study of DNA gleaned from permafrost shows we definitely did meet the mammoth in North America, and much later than had been thought

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Artist's impression of woolly mammoths
Artist's impression of woolly mammothsCredit: Denis Simonov / Shutterstock.com
Ruth Schuster
Ruth Schuster

The woolly mammoth apparently clung on in Canada despite our efforts to hunt them and the warming climate until about 5,000 years ago, according to a new study published in Nature. That is thousands of years later than had been previously thought.

The paper by researchers at McMaster University, the University of Alberta, the American Museum of Natural History and the Yukon government is based on a new technique: “capture-enrichment” of DNA from mere spoonfuls of soil. Or, in this case, permafrost – a technology that was developed at McMaster’s.

Their aim was to reconstruct the changes in animals and plants from the height of the Ice Age through the Pleistocene-Holocene transition. As the Ice Age waned and the northern hemisphere warmed during the climatically unstable period from about 14,000 to 11,000 years ago, much of the North American mega-fauna disappeared – from the mammoth to the mastodon to the giant sloth and saber-toothed tiger, and the Yukon wild horse.

Or so we assumed. The permafrost-DNA study suggests that indeed the elephantids and wild horses were indeed declining. But they weren’t dead yet, and humans – who had reached North America at least 23,000 years ago, according to recent research – had not in fact killed them off, at least not as early as thought.

The DNA found in the permafrost cores shows that both the mammoth and wild horse were still around in the Yukon 5,000 years ago, at a time, far far away in the Middle East – just to put this into perspective – when Arabia was aridifying after its last green period, and advanced civilizations were rising around the Mediterranean and in the Near East.

One sunny day in the Yukon

Mammoths reached North America via the Bering land bridge that connected the continent with Asia at least a million years ago, fossil evidence has shown. The Yukon and Alaska are believed to be where the subtype known as the woolly mammoth actually evolved, around 300,000 years ago.

They thrived, even spreading back to Eurasia via that same land bridge. The Yukon abounds in woolly mammoth fossils, some beautifully preserved.

Part of a mammoth figure is pictured in the Quinametzin, a new mammoth museum being built in Mexico.Credit: EDGARD GARRIDO/REUTERS

The samples for testing were taken from cored permafrost sediments extracted from the Klondike region of central Yukon, the researchers explain.

By 5,000 years ago human beings were firmly entrenched in the Americas, which could shed light on the following story.

In the 1990s, a local artist named Joe Pachak noticed petroglyphs on a rock face in Upper Sand Island that seem to show a mammoth (and a bison), and won scholarly support from rock art expert Ekkehart Malotki in 2011. Malotki confirmed that the art showed a mammoth and a bison, and was probably carved into the rock 13,000 to 11,000 years ago.

Some were unpersuaded, including on the grounds that mammoths were thought to be dead in that area by that time, humans were thought to have barely arrived in the region, dating rock art is a doubtful and dubious process, and more. One theory was that the artist was depicting a cultural memory – in which case the accuracy of the oral descriptions handed down over the generations is purely awesome.

What can we make of all this? Evidently, mammoths survived longer than we thought, and even though Yukon is far north of Utah, the new study does indicate that our timeline of mammoth (and wild horse) extinction in the New World is off.

So did we kill them off after all? Heaven knows early humans were eating elephants from as early as they could catch them, more than a million years ago. So, maybe we did kill off the mammoth in America. Or possibly the last woolly mammoths were unable to adapt to the change in climate. As the glaciers retreated and the weather warmed, the Yukon underwent extreme change from rich grasslands dubbed “mammoth steppe” to shrubs and mosses.

This work builds on previous research by McMaster scientists who had determined woolly mammoths and the North American horse were likely present in the Yukon approximately 9,700 years ago. Better techniques and further investigation have since refined that analysis.

A Przewalski's horse in Khomyntal, western Mongolia. Scientists deciphered the genetic code of an ancient horse about 700,000 years old based on a tiny fossil bone found in the frozen Yukon.Credit: AP

“Although mammoths are gone forever, horses are not,” stated co-author Ross MacPhee of the American Museum of Natural History. “The horse that lived in the Yukon 5,000 years ago is directly related to the horse species we have today, Equus caballus. Biologically, this makes the horse a native North American mammal, and it should be treated as such.”

Meanwhile, studies looking for and identifying ancient DNA in bones, soil, cave floors and now permafrost cores have become all the rage. Starting with the development of techniques to extract and amplify genes from ancient bones at the Max Planck Institute in Germany, it’s all very new. But there have been some startling results.

Recent discoveries include revelations on the extinction of Neanderthals: they may have bounced back from the brink in Eurasia at least twice before their final extinction there some 40,000 years ago. Researchers teasing genetic signals out of dirt detected two radical replacements of the Neanderthal population throughout Eurasia – 135,000 years ago and again 100,000 years ago.

Another example comes from the famed Denisova Cave in Siberia, where ancient DNA techniques first discovered the existence of another ancient human species, the Denisovans (cousins of the Neanderthals). That discovery by David Reich, Richard Green and Svante Pääbo was thanks to sequencing DNA extracted from a single bone.

Later, teams working on ancient DNA from Denisova Cave soil detected no less than a first-generation hybrid Denisovan-Neanderthal teenager. More recent work, checking DNA in the soil, enabled researchers to map out a timeline of the cave’s use by Denisovans, Neanderthals and Homo sapiens going back a quarter-million years.

Make no mistake, you can’t just grab a spoonful of dirt, hire a kid with a DNA-Iz-Us kit and expect results. These techniques are exquisitely complicated, but they are becoming more widely used.As Science colorfully pointed out, conditions permitting, we can now tell where a Neanderthal had a pee in a cave. We can also gain information about animals, extinct and otherwise. As was done in the case of the Yukon mammoth and horse using the wrinkle on the technique created at McMaster’s.

In fact, separate “fossil DNA” work on mammoths has been done, resulting in the successful extraction of genetic material a whopping million years old, and shedding unexpected light on the evolution of the mammoth line. This includes the existence in Siberia of two steppe mammoth lineages, not one.

People examining mammoth reproductions in a German museum.Credit: AP

And now we learn that we just missed them – 5,000 years is an eyeblink in the course of history. Yet even so, the mammoths of the Yukon were not the last ones on Earth. That sad distinction still belongs to the mammoths on the Siberian island of Wrangel, who died out only about 3,700 years ago.

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