Updated | A recently-discovered species of early human appears to have hidden its dead, indicating a more sophisticated level of intelligence and possibly even the early signs of culture.
Homo naledi is a species of hominin that lived between 335,000 and 236,000 years ago. Scientists announced its discovery in 2015 after finding a cave just outside Johannesburg, South Africa, full of its remains. It represents the richest fossil hominin site in Africa ever found.
The discovery is remarkable, because the species would have lived alongside Homo sapiens—our direct ancestors. Before H. naledi was discovered, scientists did not think any other hominin species lived at the same time as the first humans in Africa.
In three studies published in the journal eLife on Tuesday, scientists have now announced the discovery of another chamber full of H. naledi remains. Scientists found multiple individuals, including a child and the “wonderfully complete” skull of an adult male. In total, they recovered 131 hominin specimens. Of these they have so far identified two adults and one juvenile, but they believe further analysis will reveal more.
Researchers led by Lee Berger of the University of the Witwatersrand in Johannesburg, South Africa, say the presence of an additional chamber with so many remains reinforces the theory that this species purposefully disposed of their dead—in this case hiding them within the deep confines of a difficult-to-access cave.
The chamber—dubbed the Lesedi Chamber—is 30 meters (nearly 100 feet) below ground; to get to it, scientists had to use a path that twists and turns through the cave until they reached a point where only one small person could squeeze through.
John Hawks, an author on all three studies, said in a statement: “This likely adds weight to the hypothesis that H. naledi was using dark, remote places to cache its dead. What are the odds of a second, almost identical occurrence happening by chance?”
Hawks believes H. naledi purposefully hid their dead in the chamber, adding that this behaviour would indicate intelligence and possibly even culture. This mimics similar findings from a Neanderthal archaeological site in Spain, Sima de los Huesos, where researchers found evidence in 2015 of Neanderthals disposing of their dead 400,000 years ago.
“What is so provocative about Homo naledi is that these are creatures with brains one third the size of ours,” Hawks said. “This is clearly not a human, yet it seems to share a very deep aspect of behavior that we recognize, an enduring care for other individuals that continues after their deaths. It awes me that we may be seeing the deepest roots of human cultural practices.”
As well as providing a greater fossil record for this new species, the discovery also raises many questions about our understanding of the evolution of H. sapiens. Around 200,000 years ago—when H. naledi would have walked alongside our ancestors—modern human behavior was just starting to emerge. This includes self-adornment and tool use.
“We can no longer assume that we know which species made which tools, or even assume that it was modern humans that were the innovators of some of these critical technological and behavioral breakthroughs in the archaeological record of Africa,” Berger said in a statement. “If there is one other species out there that shared the world with ‘modern humans’ in Africa, it is very likely there are others. We just need to find them.”
Hawks adds: “I think some scientists assumed they knew how human evolution happened, but these new fossil discoveries, plus what we know from genetics, tell us that the southern half of Africa was home to a diversity that we’ve never seen anywhere else.”
Researchers will now try to obtain DNA from the newly-discovered fossils to compare them to those found in the first chamber. This will allow them to work out if they were close genetic relatives—something they now believe is likely. They will also be surveying more potential fossil sites that could contain more H. naledi fossils, and add they hope to make an “announcement of exciting new naledi fossils very soon.”
This story has been updated to correct an error that said modern human behavior started to emerge around 200,000 years ago; it was 300,000 years ago.