The Denisova Cave in Altai Mountains in Siberia was hot property throughout the day – at least among old people who called it home for more than 200,000 years.
This is according to researchers who date artifacts, fossils and sediments excavated from pits in the cave floor to compile a record of living.
In a pair of documents in Nature today, they report that the Denizens – the extinct kind of human whose genome was published in 2011 – occupied the cave from about 287,000 to 50,000 years ago.
This coincided with the Neanderthals, who also lived there, but for a shorter period: between 193,000 and 91,000 years.
While the timeframe was not compiled, archaeologists do not know when the Denissons arrived in the cave, says Bert Roberts, a geochronologist at the University of Wollongong and co-author of both papers.
"They could have been there a million years ago or 100,000 years ago," said Professor Roberts.
We do not know whether the Denisovites and the Neanderthals were simultaneously inhabitants of the dwellings in the cave.
But recent research "suggests that both groups lived in the region, met and – occasionally – fit for about 150,000 years," researchers said.
Fossil deep freezing
Not much is known about the mysterious Denisovci.
Their remains were found only in one place – the Denisova cave, and hence their questioning – and even then, the fossils contain a finger bone and several teeth from four different individuals and a hybrid child.
"We know very little about them," said Professor Roberts.
"We do not even know what they look like."
This is because they were not identified for the first time with a skeleton or skull, but with their DNA, obtained from the precious finger of a young girl.
The use of genetic material is possible because the cave, which is in the Siberian mountains, is like a large freezer, preserving the DNA that would normally decompose into warmer, humid climates.
Russian scientists have met and excavated the cave floor for 40 years, finding bones and artifacts as tools and pendants.4
But in order to reconstruct the time frame for living, they needed to date sediments.
The layers of dirt act as an archive of what happened in the cave at the time they were placed.
The idea is deeper digging, the more time you see.
And since the cavity sediment covers at least 300,000 years, researchers in one work had to use a number of dating methods.
They include a radioactive node, which is good up to about 50,000 years old, and optically stimulated luminescence, which measures when quartz and feldspar minerals were last exposed to sunlight.
Optically stimulated luminescence, along with some noble models, can be used by archaeologists around 300,000 years ago, said Zenobia Jacobs, also from the University of Wollongong and co-author of the papers.
In a special paper, researchers used a radioactive node to determine the age of fossil Denisovan, along with the remains of three neanderthals and a hybrid child.
They estimate that Denisova's oldest and youngest fossils were 194,400 years and 51,600 years.
The Neanderthals were between 90,900 and 147,300 years old, and the Neanderthal / Denisavian child was between 79,300 and 118,100 years, placing them widely within the dates determined by sediment analysis.
The issue of artifacts
Among the Denisov cave destinations were pendants separated from teeth and bones spear points, dating from 43,000 to 49,000 years.
So were they made by Denisovani?
The idea lies with the researchers, but Darren Courno, a paleoanthropologist at the New South Wales University, who was not involved in the work, is not convinced.
Although there are still no signs that modern humans – Homo sapiens – lived in the Denisova cave until much later, "they were not too far away in approximately the same time," he said.
Complex behaviors such as carving of jewelry are typical of contemporary people.
"And now we have claims in southern China, there were contemporary people more than 100,000 years ago," said Dr. Kuren.
"If that's true, then modern people were already in the neighborhood [of Siberia] for 50,000 years or so ".
Professor Jacobs said that the attribution of Denis artifacts would undoubtedly be controversial.
"As western scientists, we immediately assume, looking at such artifacts, can be made by Homo sapiens.
"But we have collaborators who feel quite strong that the evidence of Homo sapiens is not in the cave, no fossils or DNA, except in much later periods."
Denisova DNA in Australia
Indigenous Australians and populations of Papua New Guinea have a relatively high percentage of Denis DNA that their ancestors erected in Asia before their arrival in Australia.
Recent genetic analyzes have shown that the crossing occurred after the Altai Denisovci left the cave, said Joao Teixeira, a popular geneticist at the University of Adelaide, who was not involved in recent work.
So even though there are no traces of Denisovani after about 50,000 years in the cave – or elsewhere, because it is very small, it is likely that a certain population is the last of their kind.
"Not only is their geographical distribution likely wider than Altai … but also the nature of Denis DNA appears to indicate different Denis populations, which probably reflects geographical isolation, which will then lead to small accumulations of genetic differences, "said Dr. Teiseira.