“We need perhaps three or four individuals with excellent archaeological/paleontological and excavation skills. The catch is the person[s] must be skinny and preferably small. They must not be claustrophobic, they must be fit, they should have some caving experience, climbing experience would be a bonus.”
This plea appeared on National Geographic Explorer-in-Residence Lee Berger’s Facebook page back in 2013. It was the beginning of an extraordinary story of an unconventional scientific endeavor leading to the discovery of a new chapter in the story of human evolution.
Fresh off his find of Australopithecus sediba, Lee Berger had contracted with some local cavers to keep an eye out for early hominid fossils during their adventures in nearby caves. What they brought to him was a whole lot of pay dirt.
After traversing tight squeezes and rocky climbs with names like the Dragon’s Back and Superman’s Crawl, the spelunkers came across a small cave littered with bones. From the pictures they brought back, Berger could tell this was something special.
But Berger himself was too large to reach the find. After his then 11-year-old son, Matthew, confirmed what was in the cave, Berger made his now famous plea to the Internet.
Out of a mountain of applications, Berger selected the best qualified, called them all to South Africa, and set up base camp around the cave mouth.
Over the course of the first two excavations, Berger’s “underground astronauts” removed some 1,550 bones representing at least 15 individuals and still had a lot left to explore. They also found a second discrete chamber with a full skull and all 32 teeth. It was the richest primitive hominid site ever.
What exactly did they find?
At this point that Berger took another unconventional step. In a field where discoveries have been jealously guarded for years while a small group of scientists attempt to eke out meaning from the bones in an intellectual vacuum, Berger took the bold step of inviting qualified scientists from all over the world to make what they could of the bones.
Though this ruffled quite a few academic feathers, Berger was happy to give young people a chance to compete with their more seasoned colleagues. It was “a paleofantasy come true,” according to Lucas Delezene, a newly minted professor at the University of Arkansas. “In grad school you dream of a pile of fossils no one has seen before, and you get to figure it out.”
Their conclusion was that the bones belonged to a previously unknown species of small-brained hominid, which Berger named Homo naledi. (Need a crash course on human evolution?)
Not only that, but the context of the find—deep underground and with no other artifacts—suggests something even more extraordinary: H. naledi may have buried its dead. Such a theory indicates an advanced level of self-knowledge previously reserved for modern humans and our closest ancestors. Though controversial in academic circles, if proven to be true, this hypothesis could change our understanding of what it means to be human.
How old are the fossils?
Because of H. naledi’s very small brain case, paired with modern feet and a human-like appearance, the researchers thought they were working with a species that roamed South Africa around two million years ago. (For reference, modern humans, Homo sapiens, appeared on the scene sometime before 200,000 years ago.)
However, the mixed sediment in which the bones were discovered made it difficult to determine an accurate date. Berger’s team finally sacrificed three teeth to high-tech dating methods, which required damaging the specimens to analyze the chemicals inside.
The results were very surprising. H. naledi was between 300,000 and 200,000 years old, much younger than first imagined.
Could H. naledi have lived at the same time as anatomically modern humans, as did the hobbit-like Homo floresiensis? Did they grow apart from us and then interbreed, as did the Neanderthals? Where does this unexpected species fit in the grand picture of human existence?
Questions still abound, but one thing is certain: This important discovery will change the way we see our human family tree.