When South African spelunkers Rick Hunter and Steve Tucker went off-map and discovered a hidden chamber in Rising Star cave, about 30 miles northwest of Johannesburg, it was an incredibly lucky find.
They found and then crammed themselves through a hole that was at one point just over seven inches wide, and then travelled 50 feet down.
At the bottom they spotted a jawbone. They took photos with a GoPro, and then brought them to the the door of National Geographic explorer-in-residence Lee Berger of the University of the Witwatersrand.
Berger realised that this was big: the jaw looked like some kind of primate related to early humans. And there were more bones — many more. But it was going to require some special skills to get them out.
So he posted an ad on Facebook. “We need perhaps three or four individuals with excellent archaeological/palaeontological and excavation skills,” it read. “The catch is this — the person 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. They must be willing to work in cramped quarters, have a good attitude and be a team player.”
He ended up with six women who fit the insane physiological and academic requirements for the task, who he’d later refer to as “underground astronauts.” These six brave scientists would unearth the largest collection of hominid fossils ever discovered in Africa, a whole new species to transform our understanding of the human family tree. They called it Homo naledi.
Scroll on for the story of their fantastic expedition, which is featured in National Geographic’s October cover story.
For the initial excavation in November of 2013, about 60 people gathered -- cooks, climbers and cavers, researchers, and of course, the 'underground astronauts.'
The team first entered the chamber -- which was given the name Dinaledi, meaning many stars -- on November 10, 2013. Each trip required a 'Superman crawl' through a 10-inch passage, and then a far more daunting trip down the incredibly narrow chute into the chamber.
Anthropologist Marina Elliott squeezes through a tight spot here, but the chute was the 'real bruiser,' an expedition blog noted at the time. 'Squeezing through tiny openings, jamming knees and elbows into cracks for stability, and unavoidably swinging or banging into the countless spines and protuberances has given these explorers what amounts to temporary full-body leopard-print tattoos.'
Elliott and paleontologist Ashley Kruger explore a side chamber of the cave here. As Dr. William Harcourt-Smith, a researcher with the paleontology division of the American Museum of Natural History, who led some of the research on the fossils, tells us, this type of fieldwork was nuts -- 'some of the most difficult conditions ever for paleontologists to work in.'
The team extracted around 1,550 fossils from the chamber, but there are still thousands more in there. Anthropologist Becca Peixotto, a member of the team whom Berger describes as 'one of the six people willing to quite literally risk their lives on a daily basis,' sits in the chamber here with Elliott and archaeologist Hannah Morris.
'As busy as it was, there were moments when you were lucky enough to be the first person out there in the morning or the last person there in the evening,' surrounded by the remains of a new member of our evolutionary family tree and with dripping stalactites overhead, Peixotto said on a press call.
Tucker (shown here) and Hunter -- both now National Geographic explorers -- provided support for the team throughout the trip, along with other cavers.
Elliott and Peixotto (shown here) and the other four women settled into a routine of working six-hour shifts underground at a time. It wasn't long before they realised they had a whole collection of bodies, which researchers would later realise seem to have been deposited over a period of time. This leads them to believe these small-brained hominins were burying or stashing them in the chamber intentionally.
Getting each bone out was like solving a puzzle, says Peixotto -- they had to pass them up the jagged, narrow chute, without breaking anything along the way. They spotted a marking on the wall that indicated at some point in the 1980s, a caver had crawled down to where they were. But that anonymous, mysterious person seems to have missed the collection of fossils at their feet.
Paleoanthropologist K. Lindsay (Eaves) Hunter here checks out some scans of the underground excavation era. In one tiny section of the chamber, they found bones from 15 individuals -- enough to identify the strange characteristics of this new species.
Here are the six 'underground astronauts' along with the two cavers who first spotted the fossils (from far left, clockwise): Rick Hunter, Alia Gurtov, Becca Peixotto, Elen Feuerriegel, Steven Tucker, Hannah Morris, K. Lindsay (Eaves) Hunter and Marina Elliott.
These early-career scientists discovered a creature that shows some incredibly primitive hominid elements, like a tiny brain, one-third the size of ours -- but with feet almost like those of modern humans. This broadens the picture of the evolution of modern hominins, like us. Our past family tree is more complex than we knew.
Berger says that the fact that this small-brained creature 'had the capacity, both mental and behavioural, to deliberately dispose of its dead is a repeated fashion' is shocking. Harcourt-Smith calls it a 'game-changer,' though there's still much more to learn.
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