But how our forebears got there and how they were found were all by chance.
Nearly two-million years ago our early ancestors took a liking to the area around the Sterkfontein Caves. It was teeming with wildlife and had roomy caves to shelter them from the harsh Highveld winters. But it was a bit of a problem in terms of watching where they were walking. Several fell through holes in the porous rock, landing in deep caves that had no reachable exit. Walking around the area today is just as dangerous. Small bushes and thick grass give way to gaping holes.
Two of these ancestors – now called Australopithecus sediba – fell into one of these caves, along with several animals. Their bodies were washed into an underground lake and when this calcified they were preserved. Since then the rock has eroded, exposing their bodies.
In the mid-1990s, Professor Lee Berger of the University of the Witwatersrand’s Institute of Human Evolution decided to map more of the Sterkfontein system with a then-modern GPS system. He found 100 new caves, but nothing sensational.
In 2008 he decided to take another look, using Google Earth and some trusty boots. This led to the discovery of 600 caves and three dozen new fossil sites.
Signs of fossils
The most important of these, Malapa, was discovered while he was out mapping with his dog, Tau. He returned with the dog, his nine-year-old son, Matthew, and Dr Job Kibii and started looking for any obvious signs of fossils.
Matthew soon found bits of a skeleton – of one of the Australopithecus sediba that had fallen into that cave. This child skeleton was dubbed Karabo, because no one can know what its original name was. Karabo means “the answer” in Sesotho.
Following this discovery, the Malapa site became the focal point for a huge community of scientists and researchers. More than 80 people would eventually be involved in the project. In the past five years 240 hominid bones have been discovered, and when stuck together they form parts of five individuals of different ages.
The fossils have been so well preserved that bits of their last meals can still be found in their teeth, providing tremendous insight into their lives. This discovery went straight to the front page of the influential journal Nature last month.
And there is a final twist. Although a great deal of Karabo has been found at the site, the rest was sitting inside a metre-wide chunk of rock at the University of the Witwatersrand. Nothing was sticking out and there were none of the usual telltale clues to alert anyone. So it sat there for three years.
It was only when Berger’s wife, doing her PhD on the CT (computerised tomography) scanning of fossil material in rocks, scanned the rock as part of her degree that it became clear what was inside.
This extra detail now makes Karabo the most complete early human skeleton found to date.
To celebrate this, Berger said the university would build a laboratory at the Maropeng visitor centre in the Sterkfontein precinct. This will have a virtual connection to museums and laboratories around the world so that people can take a virtual tour of the South African fossils without having to trek to the site.
A more thorough dig of the site will begin later this year.