The treasure trove of hominin fossils from which Homo naledi emerged was discovered in the Rising Star caves in the Cradle of Humankind, in a virtually inaccessible underground chamber.
The location of the chamber and the narrow gaps that cavers must squeeze through to reach it mean that only a select few can ever hope to gain access.
Take a 3D tour of Rising Star with two of the ‘underground astronauts’ who made the daily commute deep into the underground chamber:
Researchers believe the Dinaledi Chamber has always been very difficult to reach. There’s no evidence to suggest that there was ever an easier way to get into the chamber than climbing up the Dragon’s Back and dropping down a narrow crack.
The team is also almost certain that the Dinaledi Chamber has always been in the ‘dark zone’ deep inside the caves, meaning there was a total absence of light.
Infographic courtesy Wits University.
Researchers don’t know exactly how many fossils are buried in the Dinaledi Chamber. Shallow probes in as yet unexplored parts of the chamber suggest that there are bones spread across its floor, so the Rising Star Expedition hopes to discover many more fossils as excavations continue.
The clay sediments in which the bones have been found also tell their own story. They are soft and rubbly, unlike the hard breccia deposits that are well known in the Cradle of Humankind, and are made up mainly of mud-clasts.
The fine sediments are mud-rich and derived almost completely of material that comes from the cave itself, suggesting that the Dinaledi Chamber has always remained isolated from the surface and other parts of the Rising Star system.