Archaeologists have gingerly unearthed buried remains of mammoth bones used to make a circular structure in the Russian Plains around 25,000 years ago, during the peak of the last Ice Age.
The structure – built from hundreds of bones from more than 60 mammoths – is the biggest and oldest of its kind discovered so far. But those aren’t the only unique features of this find.
Modern techniques have opened new windows into the lives of our ancestors who survived harsh conditions with long, cold winters dropping to -20 degrees Celsius, revealing that people burned wood inside and may have even sourced plant food.
“For the first time we have started to gather evidence of human behaviour and activities that took place in the middle of the circular mammoth bone structure, based on the micro-remains that were left behind,” says study lead Alexander Pryor from the University of Exeter, UK.
“This is significant because it provides a whole new category of evidence for reconstructing what these enigmatic sites were used for.”
Previous discoveries revealed that Palaeolithic people made large, circular structures from mammoth bones right across Eastern Europe, tantalising archaeologists to explore why and how they were made.
Kostenki 11, south of Moscow, is one of the most famous of these sites, with two other large mammoth bone structures that were first excavated in the 1950s and 60s dated to around 22,000 years ago.
Using the latest radiocarbon techniques enabled the researchers to date the latest structure at about 3,000 years earlier.
They analysed sediment samples from across the structure’s interior, pits and surrounding area using a technique called flotation – placing sediments in a tank filled with water on top of a fine mesh.
“Burnt plant remains are released from the sediments and float to the top where they can be collected,” Pryor explains. “The sediments are then broken up and settle through the mesh to the bottom of the tank, while small objects contained within the sediments such as microlithic chips are caught inside the mesh.”
A key discovery was large amounts of charcoal, evidence that trees were still around and used to burn wood for fuel. They also found charred remains of softer, starchy plant tissues typical of roots and tubers.
“This plant food component is particularly interesting, as it is the first time evidence for this has been recovered from sites like this,” says Pryor.
The microlithic chips are useful for reconstructing human stone tool use inside the circle, he adds. “This was interesting because the concentration of lithic remains was much lower than expected for a site that clearly took such time and effort to build.”
While it’s tempting to conclude that the structure was used as a house, such evidence is not consistent with the activity that would have occurred during long-term occupation, raising questions about its purpose.
While most other places with similar hostile conditions had been abandoned at this time, it seems the mobile hunter-gatherers who built this structure managed to find food, shelter and water, and it’s possible they stored their food there.
For now, though, the new discovery has provoked more questions than answers.