Denisova Cave in the Altai Mountains of Siberia was a hot property at that time – at least for ancient people who called it a home for more than 200,000 years.
This is according to the researchers, who dated artifacts, fossils and sediments dug from the pits on the cave floor to put together records about housing.
In a couple of articles in the journal Nature today they report that the Denisovs, an extinct species of a man whose genome was registered in 2011, occupied the cave about 287,000 to 50,000 years ago.
This coincided with Neanderthals who also lived there, but for a shorter period: between 193,000 and 91,000 years ago.
According to Bert Roberts, a geochronologist at the University of Wollongong and co-author of both works, until the time scale was compiled, archaeologists did not know when the Denisovites arrived at the cave.
“They could have been there a million years ago or 100,000 years ago,” said Professor Roberts.
We do not know whether Denisovites and Neanderthals were classmates living in a cave at the same time.
But recent studies "suggest that both groups lived in the region, met and – sometimes – crossed for about 150,000 years," the researchers said.
Little is known about the mysterious Denisovites.
Their remains were found only in one place – Denisova Cave, hence their nickname – and even in this case the fossils make up the finger bone and several teeth from four separate individuals and a hybrid child.
“We are annoyingly little about them,” said Professor Roberts.
"We don't even know what they looked like."
This is because they were first identified not by the skeleton or the skull, but by their DNA, scraped off the precious finger of a young girl.
The use of genetic material is possible because the cave, located in the Siberian mountains, is similar to a large freezer that preserves the DNA, which usually disintegrates in a warmer and more humid climate.
Russian scientists have known the cave floor for 40 years, finding bones and artifacts such as tools and pendants.
But in order to restore the timeline of housing, they needed to date deposits.
Layers of dirt act as an archive of what was happening in the cave at the time when they were laid.
The idea is that the deeper you dig, the farther back you are in time.
And since the sediments in the cave cover at least 300,000 years, the researchers in one document had to use a number of dating methods.
They included radiocarbon dating, which is about 50,000 years old, and an optically stimulated glow, which measures when the minerals of quartz and feldspar were last exposed to sunlight.
According to Zenobia Jacobs, also from the University of Wollongong and co-author, the optically stimulated glow, along with some elegant models, can return to archaeologists about 300,000 years ago.
In a separate article, researchers used radiocarbon dating to determine the age of Denisovan fossils, as well as the remains of three Neanderthals and a hybrid child.
According to their estimates, the oldest and youngest Denisovan fossils were 194,400 years old and 51,600 years old, respectively.
Neanderthals were from 90,900 to 147,300 years old, and Neanderthals / Denisovans were from 79,300 to 118,100 years old, which in a broad sense corresponded to the dates determined by sediment analysis.
Question about artifacts
Among the caves of Denisova Cave were pendants cut from the teeth and bone tips of spears, dated from 43,000 to 49,000 years.
So they were made by Denisov?
This idea was expressed by researchers, but Darren Kurnoi, a paleoanthropologist from the University of New South Wales, who was not involved in the work, is not convinced.
Although so far there are no signs that modern people — Homo sapiens — lived in Denisov's cave much later, “they were not too far at about the same time,” he said.
Complicated behaviors, such as carved decorations, are typical of modern humans.
“And now we have claims that there were modern people in the south of China more than 100,000 years ago,” said Dr. Kurne.
"If this is correct, then modern people were already in the neighborhood [of Siberia] for 50,000 years or so. "
Professor Jacobs said that the attribution of artifacts to Denisovans will undoubtedly be controversial.
“As Western scientists, we immediately assume that by looking at such artifacts, they can be created by Homo Sapiens.”
“But we have employees who firmly believe that there is no evidence of Homo Sapiens in the cave, no fossils or DNA, except for much later periods.”
Denisovan DNA in Australia
The indigenous people of Australia and Papua New Guinea have a relatively high percentage of Denis's DNA, which their ancestors found in Asia before arriving in Australia.
A recent genetic analysis showed that the crossing of the Altai Denisovans occurred after the Altaians left the cave, said Joao Teixeira, a population geneticist at the University of Adelaide, who did not participate in recent work.
Thus, despite the absence of traces of Denisovites after 50,000 years ago in a cave – or somewhere else, in this respect – it is very unlikely that a particular population was the last of their species.
“Not only is their geographic distribution probably more widespread than Altai … but also the nature of Denis's DNA seems to indicate different Denisov populations, which probably reflects geographic isolation, which then leads to a small accumulation of genetic differences, ”said Dr. Teixeira.