Deep in a cave in southwest France, closed off from the outside world for tens of thousands of years, researchers have discovered evidence of early human construction. But the ring-like structure with partitially standing walls, formed from hundreds of chunks of stalagmites dates to around 176,000 years ago, meaning that it wasn’t modern humans who created it, but our Neanderthal cousins. The findings are published this week in Nature.
The Bruniquel cave was originally explored in 1990 when spelunkers broke through the entrance, thought to have been sealed for thousands of years. Inside they found tantalizing traces of cave bears, now extinct, who had used the cave for hibernation. Their footprints, claw marks, fur and hibernation hollows were all preserved in the soft floor of the interior.
Two of the most promiment rings are shown here. The larger one is 6.7 meters (22 feet) across, while the smaller one is 2.2 meters (7.2 feet). Xavier MUTH - Get in Situ/Archéotransfert/Archéovision -SHS-3D/base photographique Pascal Mora
But further into the system, some 336 meters (1,102 feet) from the entrance, the cavers discovered something far more intriguing: a series of ring-like structures, semi-circles, and smaller piles all constructed using broken pieces of stalagmites. Was this a natural formation, or something far more interesting?
Yet it wasn’t until 2013 that researchers, led by Jacques Jaubert from the University of Bordeaux, were able to get down into the cave and study the structures. Dating 18 samples taken from the area containing the structures, using a variety of techniques, the team came to the date of 176,500 years old, plus or minus 2,100 years.
Each structure is made up of pieces of stalagmite roughly the same size, with structures having chunks stacked on top of each and in some cases supported by other pieces to stop the “walls” from toppling. Ruling out the architect being a bear, as they do not fit with any other known bear nests, there is only really one other answer.
The rings are found over 300 meters from the entrance to the cave. Etienne FABRE - SSAC
As early Neanderthals were the only humans living in Europe at the time when the structures were constructed, it seems reasonable to conclude that they were indeed the builders. This is backed up by the discovery of charred bone found within one of the smaller structures, thought to be from either a bear or large herbivore. This makes the structures not only the oldest known constructions attributed to Neanderthals, but also some of the earliest known to have been made by hominins.
While the purpose of the structures may remain elusive, there are some hints. Many of the pieces of stalagmite seem to have been burnt, and there is even evidence of a hearth within the cave. But what this construction can tell us is how some forms of modern behavior existed within Neanderthal populations earlier than previously thought. To build them it would require social organization, the control of fire, and the exploration and exploitation of cave systems.
Only further discoveries of other structures further within the cave will hint at whether or not the building of the ones so far studied were opportunistic, or formed part of a regular or planned Neanderthal visit to the cave system.