Science Interviews

New Evidence from Old Caves

Kelvin -   There’s a cave system called the Wonderwerk Cave System, and it is in rocks that are 2 billion years old, some of the oldest rocks on Earth.  The cave itself has been dated at 2 million years old, which is more than twice as old as the oldest other cave in Spain which has been dated to about 800 thousand years ago, where it was known that people intentionally lived in caves.  So what this means now is it has been found that human beings were intentionally living in this cave some 2 million year ago, which is quite amazing.  It’s very big, by the way, it’s 2,500 square meters, quite sizeable – if you look at pictures of it, you can drive a double decker bus into parts of the cave.

The depth of the sediment that’s in the cave is some six metres, they’ve dug down through the six meters and found nine layers that go right back as far as 2 million years.  At the 2 million years ago level, tools have been found and an indication of the intentional use of fire and suchlike.  Now what’s interesting is that the humidity in the area is so low that the amount of water precipitation inside this cave is one millimetre per year – in other words there’s nothing in there.  So this is why it’s been so dry for so long.  It’s also clearly the case that the tools were left there and not washed there.  The cave is, in fact, about 140 metres deep, but it’s horizontal into the rocks, therefore there’s been no water flow over the years so these materials couldn’t have been washed down to the bottom.

Meera -   Now what tools have the actually found down there?

Kelvin -   Well, there’s primitive hand axes and there’s also some ornamental stones as well that have got some shaped lines on them – so there’s ‘artwork’ so to speak on some of these very old stones that have been found down there. 

Meera -   Which of our ancestors is thought to have lived there?

Kelvin -   It appears to be Homo habilis.  There were numbers of different types of pre-humans that were living at the time and of course the Homo sapiens, which is us, the one that won out at the end of the day.

Meera -   What else has managed to have been learned from the findings in this cave?

Kelvin -   Something that is very interesting is that hand axes were found in the cave that were dated to 270 thousand years ago, which is when they were last being made there.  However, they continued to be made in East Africa up to 130 thousand years ago and in Europe 40 thousand years ago.  Meantime, in South Africa the technology had moved on to what we call convergent points, this is like a more modern arrowhead, with two sides or cuts to make a point.  So what it now indicates is that the technology of the making of tools originated here in South Africa and moved from here up to Europe, and then was defined to a great degree in Europe.  Previously, it was thought that the technology was developed there and then moved back down to Africa and elsewhere, but that appears not to be the case now.

February 2009