Tue. Dec 7th, 2021

Mammoths and other giant creatures of the Ice Age like woolly rhinos survived longer than scientists thought and lived with humans for tens of thousands of years before disappearing for good.

It shows the results of an ambitious 10-year research project that analyzed DNA from hundreds of soil samples throughout the Arctic.

The researchers involved in the project collected 535 samples of permafrost and sediment from frozen lakes, often in extremely cold locations from across Siberia, Alaska, Canada and Scandinavia, at 73 locations where mammoth remains have been found.

Analysis of DNA contained in the earth showed that mammoths lived on the mainland of Siberia 3900 years ago - after the Great Pyramid of Giza was built in Egypt and the megaliths of Stonehenge were erected.
Analysis of DNA contained in the earth showed that mammoths lived on the mainland of Siberia 3900 years ago – after the Great Pyramid of Giza was built in Egypt and the megaliths of Stonehenge were erected. (Beth Zaiken / Center for Paleogenetics)

Analysis of DNA contained in the earth showed that mammoths lived on the mainland of Siberia 3900 years ago – after the Great Pyramid of Giza was built in Egypt and the megaliths of Stonehenge were erected.

Most woolly mammoths were former believed to be dead about 10,000 years ago, except for a very small population that survived on remote islands off Siberia.

Wool rhinos, the researchers said, were still roaming the Arctic 9800 years ago.

Previous studies said they became extinct about 14,000 years ago.

Instead, the extinction came when the last areas of the Mammoth Steppe – a unique ecosystem in the Arctic that does not exist today – gave way to peatlands as the climate became warmer and wetter.

“The authors present more dates for mammoth, woolly rhinoceros, horse and steppe bison, which are also significantly younger than the fossil record indicates, building a stronger case for late survival over the Arctic than has been done in the past,” Tori Herridge, an evolutionary biologist and mammoth specialist at the Natural History Museum in London, said.

“I am very excited to see how this work develops and what new data may emerge to support or disprove this. I am sure it will be examined intensively.”

Mrs Herridge was not involved in the research.

Most ancient DNA is typically taken from bones or teeth (the oldest DNA ever sequenced was from a mammoth tooth and was more than 1 million years old), but new techniques mean that genetic material preserved in soil can now be analyzed, dated and sequenced.

All animals, including humans, constantly shed genetic material when they urinate, pop and bleed, lose hair and knock down dead skin cells.

This genetic material is leached into the soil, where it can remain for tens of thousands, if not hundreds of thousands of years, when conditions are right – e.g. In frozen soil.

“A single animal continuously spreads DNA throughout its life in its manure, urine, epidermal cells and hair containing millions of DNA segments while migrating over its full geographical area, leaving only a skeleton at its death, which is far less likely to be preserved, restored and dated, “said one of the study’s authors, Yucheng Wang, a research assistant at the Department of Zoology at the University of Cambridge.

“By sequencing only a few of these DNA molecules that are conserved in the environment, we can identify its existence and range. It is therefore not surprising that sedimentary DNA could produce a later and more accurate eradication estimate.”

Known as the environment or eDNA, the technique has been used by archaeologists to shed light on ancient humans, and the same method has also been used during the pandemic to test human wastewater to detect and track COVID-19.

Why large grazing animals like the extinct mammoth have been debated for more than 100 years
Why large grazing animals like the extinct mammoth have been debated for more than 100 years. (AAP)

The study, published in the journal Nature, has also described the Arctic ecosystem for the past 50,000 years.

The environment in which mammoths lived, known as Mammoth Steppe, was cold, dry and regionally complex, with a distinct vegetation community consisting of grasses, sedges (a grass-like plant), flowering plants and shrubs.

As part of the research, the team sequenced DNA for 1,500 Arctic plants for the very first time.

Why large grazing animals like the mammoth extinct have been debated for more than 100 years, Wang said.

There are two main theories: Mammoths were chased to death within centuries of their first contact with humans, or they were unable to quickly adapt to a rapidly changing climate at the end of the ice age.

Israeli diver Shlomi Katzin was on a weekend dive off the country's Mediterranean coast when he discovered a crowd of ancient artifacts.  Including this sword.  Incredibly, he was only about 150 meters from the shore, in five meters deep water, when he found the find.  Fearing that the weapon would be lost in changing sand, he brought the weapon ashore.  Experts say it originated from the Crusaders and is 900 years old.

Israeli diver finds old weapon during weekend diving

Wang said their research supported the theory that climate change at the end of the last ice age 12,000 years ago played the major role.

The longer overlap between humans and mammoths in the Arctic region, along with a detailed understanding of the Mammoth Steppe ecosystem and how quickly it changed, reinforced the case against the idea that humans were the main driver of mammoth extinction, Wang explained.

“As the climate got wetter and the ice began to melt, it led to the formation of lakes, rivers and marshes. The ecosystem changed and the vegetation biomass reduced and would not have been able to sustain flocks of mammoths,” Wang said.

“We have shown that climate change, especially precipitation, directly drives the change in vegetation – humans had no influence at all on them based on our models.”

The teeth of what is believed to be a 23,000-year-old wool mammoth are carried on a reindeer sleigh.  (AAP)
The teeth of what is believed to be a 23,000-year-old wool mammoth are carried on a reindeer sleigh. (AAP)

Mrs Herridge at the Natural History Museum said more work needs to be done on the human presence in Mammoth Steppe if a human role in the disappearance of mammoths is to be ruled out.

In the models used in this paper, she said, scientists used the scarce presence of human remains in the archaeological record and the existence of a climate suitable for humanity as a substitute, not DNA.

Much finer data is needed to understand if and when humans and mammoths actually overlap in these regions.

“Environmental DNA studies like this have great potential to directly test for human presence over time in the Arctic in much the same way they have done here for mammoths – it’s the kind of high-resolution data we have to tease apart from the true dynamics of the Arctic. the extinction of the woolly mammoth, ”she said.

“Overlap data alone will not cut it off, as it is not the last mammoth that matters, it is figuring out what drove mammoth numbers so low that they were reduced to just a few isolated and vulnerable populations.”

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