On a cool overcast morning about an hour north west of Johannesburg, South Africa, postdoc researcher Marina Elliot walks past horses grazing in a farmer’s field and disappears into a small stand of trees. She scrambles down a rocky path and emerges into a large cave. It doesn’t look like anything special—hundreds of caves just like this dot the landscape here. “You would never know this is something earth shattering,” she says. “But it definitely is.”
Deep inside the Rising Star cave system, in a remote chamber nearly impossible to access, lie thousands of bone fragments that may be from a newly discovered species of hominin, an ancient evolutionary ancestor to modern humans. Elliot is part of a team of researchers and cavers, led by paleoanthropologist Lee Berger, who excavated the remains of the creature now known as Homo naledi, or “star” in the Sotho language. “This fossil will be probably one of the best known hominin species discovered in the history of this science,” says Berger, who is a research professor at the University of Witwatersrand in South Africa and a National Geographic explorer-in-residence. It’s a bold statement backed by an unprecedented number and variety of fossils.
Over the course of 21 days in November, 2013, Berger’s team unearthed 1,550 individual hominin bone fragments, more than had previously been discovered in 90 years of exploration in Southern Africa.
The bones come from as many as 18 individuals—male and female, infants to elders. “If you’re an anthropologist this is as good as it gets,” says John Hawks, a professor of anthropology at the University of Wisconsin and one of Berger’s collaborators. Hawks says anthropologists have struggled to understand how our ancestors developed before we were human partly because “we just haven’t had fossils that represent the whole life span.”
Berger believes that is about to change. “There are going to be a lot of sacred cows that die with the announcement of this species,” he states confidently.
Out of Georgia
Berger’s interest in exploration began in a much less exotic location—rural Georgia. “My passion from a very early age was when I discovered Native American artifacts in the plowed fields. I would go out and hunt them and literally spend days and days trolling along these fields,” he recalls.
Berger’s graying blonde hair and blue eyes cap an infectious smile. At 49 years old, he is relatively young for his field, and his enthusiasm to explore and hunt for treasures is reminiscent of a little boy in the plowed fields of Georgia. “I love the process of discovery, the process of exploration. I love seeing new things,” he says. Yet for a middle-class kid from outside Sylvania, Georgia, a rural town of 800 people, “explorer” was not exactly a career option his family encouraged. They wanted him to be a lawyer and go into politics, so Berger went to Vanderbilt University, majored in pre-law, and failed all of the major’s courses.
It wasn’t until he read Don Johanson’s seminal book Lucy that Berger was inspired to follow his passion. He transferred to Georgia Southern University where he studied paleoanthropology. Close to graduation, he learned that Johanson was going to be in Georgia for a lecture, so Berger dialed his paleoanthropology hero and invited him to stay at his parent’s beach house instead of a hotel.
At the end of the visit, Johanson invited Berger to serve as a geological assistant on a dig at Olduvai Gorge in Tanzania. “All I had to do was get to Nairobi, and he’d arrange everything else.” Naturally, Berger accepted the offer. Unfortunately, Johanson’s field season was canceled, but Berger still made it to Africa as a part of Harvard University’s Koobi Fora field school. His first day there he says he found hominin bones—a femur and next to it a humerus. “And I was hooked,” he says.
Homo naledi
Back in his office at Witwatersrand, Berger sits in a leather armchair. Casts of hominin skulls rest atop bookshelves that line the room, and another skull, like a paperweight, sits on a trunk in front of him beside a steaming cup of coffee. Berger is animated and visibly excited over his most recent find—what he describes as the newest member of our genus, H. naledi, the details of which were published today in the journal eLife.
“This creature looks like it sits at the base of our entire lineage,” he says. H. naledi’s brain is about a third the size of a modern human’s, which would make it the smallest in the genus. Berger describes the shoulders as very primitive. The hands are advanced but curved with a long thumb suitable for climbing trees like earlier hominin species. The spine is skinny, and the pelvis is flared like a primitive hominin. “The feet are practically indistinguishable from modern humans. This is a walker!” Berger exclaims. “We think it sits right there at the base of an experiment demonstrating this adaptive radiation of our genus that we had no idea existed. But perhaps that’s not the most amazing thing about this discovery.”
Berger leans forward, and a wide smile spreads across his face as he puts the cherry on top of his sundae. “We are going to tell the world that this nonhuman animal deliberately disposed of its dead in that chamber. It implies they probably recognized their own mortality and took some level of risk to move into that deep dark zone of the chamber to make sure their dead weren’t touched by the external environment in perpetuity.”
Humans are the only creatures known to purposefully bury their dead, a custom that arose between 60,000 and 80,000 years ago. Berger’s team hasn’t been able to date the H. naledi fossils yet, and many of his claims rest on accurate dating. Radio carbon dating is only effective on artifacts up to 50,000 years old, and while there are other techniques that can stretch back millions of years, they don’t work well with the sediments found in the Rising Star cave. For Berger, the exact age of this new species is not that important. “No matter how old these are, it’s going to transform our field.”
If it turns out that H. naledi is extremely old and indeed sits at the base of human evolution, then Berger suggests perhaps modern humans inherited this practice of burying our dead from H. naledi. Perhaps other hominins besides modern humans and Neanderthals also buried their dead, but we haven’t found the burial sites yet because maybe scientists haven’t been looking in the right location, Berger suggests. “If you’re an archeologist and drop down on Johannesburg in a million years you’d find offices, restaurants, cows, pigs, cats but you probably wouldn’t hit a human unless you dropped on that 0.1% of the area that is a cemetery or a morgue.”
However, if H. naledi turns out to be a relatively recent species, say just 10,000 to 20,000 years old, Berger wouldn’t be disappointed. Ever the optimist, he would reinterpret it this way: “Another species of animal stood side by side with us at any point in time with a level of complexity of that of a modern human in the way it thought about itself and the environment.”
And that, he continues, would send ripples through our understanding of our own history. “Think of the study of archeology where we don’t have direct association of human remains. Would we ever know if that stone tool that we thought was made by modern humans—what if they made it? What about that fire pit, the ultimate level of complexity of modern humans?”
Courting Controversy
Those are wildly speculative hypotheses, the sort which Berger’s peers have criticized him for propagating in the past. “Lee likes to tell as good a story as he can,’ ” says William Jungers, chair of anatomical sciences at Stony Brook University.
Jungers doesn’t dispute that the H. naledi bones belong in the genus Homo and were likely deposited deliberately, but he cautions against “trying to argue for complex social organization and symbolic behaviors.” There may be a simple answer. “Dumping conspecifics down a hole may be better than letting them decay around you.” He suggests it’s possible that there was once another, easier, way to access the chamber where the bones were found. Until scientists can know the approximate age of the Homo naledi fossils, Jungers says they are “more curiosities than game changers. Intentional corpse disposal is a nice sound bite, but more spin than substance.”
Jungers is more dismissive of Berger’s suggestion that we may have inherited the practice of burying our dead from H. naledi, a creature with a much smaller brain than modern humans. “That’s crazy speculation—the suggestion that modern humans learned anything from these pin heads is funny.”
Some of Berger’s other extraordinary claims have drawn fire from his peers who say they lack the meticulous research necessary to back them up. “Detailed analysis doesn’t appear to be his strength,” says Patricia Kramer, an associate professor of antropology at the University of Washington. In 2008, for example, he was first author on a paper published in PLOS One describing a set of small-bodied fossils from the island of Palau. He hinted the bones might belong to a new species of pygmy-type humans, which owed their small size to a lack of nutritional resources on the South Pacific island.
The discovery was popular with the media. Berger was featured in a National Geographic documentary and magazine article about the excavation, but in academia, the find was discredited. Scott Fitzpatrick published a rebuttal to Berger’s findings, also in PLOS One. He argued that Berger based his research on an insufficient sample size and that the island traditionally had an abundance of food, which didn’t argue in favor of pygmies. Ultimately, the fossils turned out to be juvenile modern humans. “He’s a great story teller in part because he’s excited about what he’s doing,” Jungers says. “When Lee gets in trouble is when he takes off his scientific hat and puts on his salesman hat. That’s when people start to roll their eyes a bit.”
In 2010, Berger announced the discovery of another new hominin species, Australopithecus sediba, another small-brained bipedal ape. His analysis found that A. sediba was a strange mixture of primitive and advanced features, with arms like apes but an ankle bone like a modern human. A. sediba is remarkable discovery by most accounts, but Berger drew criticism when he argued for a close relationship between A. sediba and the genus Homo. Many of Berger’s colleagues thought he was trying too hard to create a connection that didn’t exist. At 2 million years old, his critics argued, sebida is too recent to be a direct ancestor of Homo. “That’s where Lee got the most grief—that sediba had implications for our genus Homo,” Jungers says.
Disagreement is common, even healthy, in science. “If you have three paleoanthropologists in a room there will be five opinions,” Kramer says. “Do I accept anything as gospel truth? No, of course not.”
In some circles, Berger’s academic pedigree also works against him. Kramer points out that Berger doesn’t come from “the strongest lineage,” meaning he didn’t graduate from one of a handful of prestigious paleoanthropology universities. “Paleoanthropologists are a bunch of silver back gorillas,” she says. Researchers from elite programs “support each other as all good primates do. He’s not one of those. So the new brash guy on the block is always going to be a lightening rod.”
Berger is no stranger to controversy and has thick skin for it. “Controversy isn’t a dirty word” in science, he says. “If you aren’t creating controversy and changing the fundamental ways, then perhaps you’re not pushing the boundaries of science. You are conforming. That perhaps is a dirty word in science.”
Paleoanthropologists often take years, sometimes decades, to publish their work. Ron Clarke has famously spent the last 18 years excavating and describing a fossil known as Little Foot, which was found in the same area of South Africa as A. sediba and H. naledi.
In contrast, it took Berger just three years to excavate the A. sediba bones and publish 13 papers in the journal Science. For many of Berger’s peers like Carol Ward, director of anatomical sciences at the University of Missouri, that breakneck pace resulted in sloppy work. “I’m working on a fossil from Kenya, and I wanted to compare it to sediba,” she says. “In one set of papers, they have one set of measurements, and in another set of papers it might be different.” Ward adds. “There were inconsistencies. It was hastily done, and I think the quality suffered.”
Unconventional Excavation
None of that has stopped Berger from plowing forward, both with his digs and breakneck publication pace. Along the way, he’s also hoping to break paleoanthropology out of what he calls its lethargic pace of discovery. Berger believes the best way to advance the field is to make new information available to the community as quickly as possible and allow his colleagues to form their own hypothesis. To describe the H. naledi fossils in quick succession, Berger recruited nearly 60 scientists from across the discipline. “It’s been said many hands make light work. Many minds make better science,” he says.
To retrieve the fossils, cavers had to negotiate a series of tight squeezes, including a 7.5 inch gap and a chute six feet long where the only option is to lay on your stomach and push yourself forward with your toes. “I didn’t know how I was going to find tiny people with extraordinary skills to work in the cave,” Berger says. “So I did what my generation does. I turned to social media.” Berger says he posted an ad looking for people who are “skinny and not claustrophobic, they must work well with others, drop everything in three weeks and come to South Africa—unpaid. Oh, and have a PhD or masters in paleoanthropology.” To his surprise, Berger had 57 applicants in ten days, 80% of whom where young women.
Elliot, the postdoc who guided me to the cave, is one of the six small-framed women that Berger selected for the excavation team. She had just finished her PhD at Simon Frasier University when she saw Lee Berger’s ad and jumped at the opportunity to get in on the ground level of what she describes as traditionally “an old boy’s network.”
The social media outreach for qualified scientists was just the beginning of the media blitz. H. naledi has been the subject of blogs, a Twitter feed, a video series, a two-hour NOVA film, and a National Geographic feature. Berger says it’s his duty to share his discoveries about our human heritage with as wide an audience as possible, and he sees social media as the best way to do it. “It’s about communicating the adventure of exploration and science in a way that the majority of humans are using right now. What other way should we do it? Newspapers?”
Some of Berger’s colleagues feel his showy approach dilutes the science, but Elliot says it’s that type of showmanship which ensures the work can happen to begin with. “The fact is, he gets funding for something like this as a result, which is huge because without that the science doesn’t continue.”
Redemption
A decade before the discovery of H. naledi, Berger wrote two books which received scathing reviews. George Washington University professor Bernard Wood wrote a review of Berger’s first book, In the Foot Steps of Eve, for the South African Journal of Science. He said the book “exceeds by literally an order of magnitude the mistakes and errors I have ever encountered in a book.” In the same publication, paleoanthropologist Tim White from the University of California wrote an even less charitable review, using phrases such as “grandstanding,” “self-promotional hype,” and “pattern of fabrication.” White said Berger’s book “signals a new era: one of smoke and mirrors, in which style triumphs over substance.”
That was in 2002. Since then, Berger has discovered two new species of hominins and shared his findings with unprecedented openness, including holding workshops so other experts could inspect the fossils before he had published them. “Lee was considered something of a media darling without much substance. Well, listen, he’s got all the substance in the world now,” Jungers says. “I’m willing to write off stuff in the past as an eager young paleontologist that wanted to make a name for himself. He’s far down the road to rehabilitating his image with the fossils he’s found and his way of dealing with them. I think he’s going to be a spokesman for our field in the future.”
Regardless of how people feel about Berger, the Rising Star discovery has granted him some measure of power within the community. Paleoanthropology is a study of comparisons, and in order to know where any given hominin species fits into the grand scheme of human evolution, scientists need to compare their work with other rare fossils. Because the H. naledi remains are so abundant and represent the full life span of a new species, other researchers will have to compare their fossils to Berger’s in order to do any significant work, though that demand may be tempered if he can’t nail down the date. “Some people like him and some people don’t, but he’s got the fossils,” Jungers says.
And there’s likely more to come. Berger’s team has literally just scratched the surface of the Rising Star cave. In just three weeks, they excavated an area less than three feet square and a foot deep. In that time, they found more fossils than the century’s worth of work that preceded them. Berger can see more fossils scattered across the cave floor and estimates there are tens of thousands of bones yet to be removed and described. He could spend the rest of his life excavating this find and leave behind a colossal body of work, but that’s not his plan.
Instead, Berger intends to engage the scientific community on how to proceed with this largesse and build a team to work on H. naledi so he can be free to continue his true passion—exploration and discovery. “Am I going to stop exploring? Not a chance. This isn’t the last discovery, I can assure you of that,” Berger says. “I hope that I’m remembered for the next thing I find and not these.”