Indiana Jones had to deal with snakes and giant boulders, but at least he wasn't crawling through narrow subterranean passages with evocative names like Dragon's Back. Jones didn't hunt bones, either, but he would've respected the courage of the small-framed adventurers who were crucial to discovering a new human ancestor, Homo naledi.
In a report as deep as the cave where these revolutionary H. naledi fossils were discovered, National Geographic explored the remarkable new find first described in eLifeas "a new species of human ancestor" with primitive characteristics, including "a tiny brain (...) and apelike shoulders."
The true age of the fossils is still in dispute, and it seems like scientists are still figuring out what they truly mean in terms of understanding human evolution. But what is not in dispute are the ballsy measures scientists took to recover the bones from the forbidding naledi "Rising Star" cave, west of Johannesburg, South Africa.
Graphic: National Geographic
After learning of the discovery of the fossil bones by adventurous spelunkers Steven Tucker and Rick Hunter in 2013, American paleoanthropologist Lee Berger took on the challenge of digging them up and figuring out what they were. Berger, a big man, realized he couldn't get through tiny Rising Star passages like "Superman's Crawl." He posted a notice, reported National Geographic, for "skinny individuals" with backgrounds in science and knowledge of caving who didn't mind working in "cramped quarters."
Berger ended up with six young women who knew science and obviously had absolutely no claustrophobia. He called them, National Geographic reported, his "underground astronauts." The crew, working with dozens of presumably larger colleagues aboveground, worked two hours at a time and eventually hauled up more than 400 fossils.
Berger and his team were able to put together full skeletons, a valuable source of archaeological data for assessing this newly-discovered human ancestor. According to National Geographic,H. naledi combines these apelike qualities with distinctly modern features. Paleontologist Steve Churchill gave National Geographic a concise description. "You could almost draw a line through the hips" of the full skeleton, he said, "—primitive above, modern below."
Additionally, H. naledi's hands were chimp-like, with distinctly curved bones that would have aided in climbing and hanging in trees, but its lower body was comparable to a bipedal, modern human's, as were many features of its jaw. The fossil's skull, however, was reportedly "less than half" the size of a modern human's dome.
But a ton of mysteries remain—just how smart was this early ancestor? Did it make use of tools with its handy opposable thumbs? And maybe most puzzling—why did the cavemen deposit bodies at the bottom of that terrifying and narrow cave? Berger's "underground astronauts" found no sign the hominids actually lived inside Rising Star, nor any evidence their bodies had somehow been washed into the space.
This is fascinating, thick, and full-bodied science, but we just want to shake the hands of lean and hungry young researchers who had the courage to spend two hours a day threading through passages no more than 10 inches wide, just so they could bring back mysterious fossils.The underground astronauts are the real heroes here.
Photos by National Geographic/Screengrab from GIF