Homo naledi is an extinct human species discovered in 2013 inside the Rising Star Cave system in South Africa’s Cradle of Humankind. What makes it remarkable is its strange mix of traits: a brain roughly a third the size of ours, combined with body features typically seen in much more modern human species. Even more controversial, some researchers believe this small-brained species buried its dead, a behavior previously thought to require a much larger brain.
How Homo Naledi Was Found
In October 2013, cavers Rick Hunter and Steven Tucker squeezed through a narrow passage in the Rising Star Cave system and found a chamber littered with ancient bones. The expedition was led by paleoanthropologist Lee Berger, and the chamber, named the Dinaledi Chamber, eventually yielded fossils from at least 15 individuals. A nearby passage called the Lesedi Chamber contained another 133 specimens representing at least three more individuals: two adults and a juvenile.
The sheer number of fossils was unusual. Most hominin species are known from a handful of bone fragments. Homo naledi gave researchers an extraordinarily complete picture of what a single species looked like, from skull to foot.
A Body Built From Two Eras
Homo naledi’s anatomy doesn’t fit neatly into the human family tree. Its brain volume measured between 450 and 600 cubic centimeters, compared to the modern human average of around 1,400. That puts it in the same range as Australopithecus, the much older group of human ancestors that includes the famous “Lucy.” Its overall body size was also small, overlapping with larger Australopithecus specimens rather than the bigger-bodied Homo erectus that came before modern humans.
But from the waist down, Homo naledi looked surprisingly modern. It had elongated lower limbs, similar to Homo erectus and later human species, suggesting it walked upright efficiently. Its level of size difference between males and females was also low (less than 20%), which is a pattern seen in more recent human species rather than in the older, more ape-like ancestors. So the overall body plan combines a small brain and small body with legs and proportions that wouldn’t look out of place on a much more “advanced” species.
When Homo Naledi Lived
This is where things get especially interesting. Direct dating of the Dinaledi Chamber fossils places them between 236,000 and 335,000 years ago. That’s the later Middle Pleistocene, a time when early Homo sapiens were already emerging in Africa. Researchers initially expected a species with such a small brain to be millions of years old. Instead, Homo naledi was walking the same continent as our own ancestors, potentially at the same time.
This timing challenges the simple narrative that bigger brains steadily replaced smaller ones over time. Homo naledi survived with a brain one-third the size of ours well into an era when large-brained species dominated.
The Burial Controversy
The most heated debate around Homo naledi centers on what the bodies were doing deep inside a cave that is extremely difficult to access. Lee Berger’s research team published evidence in 2023 arguing that Homo naledi deliberately buried its dead. They identified at least three burial features in the Dinaledi Chamber and Hill Antechamber where bones were found in anatomical position: ribs still in order, teeth still aligned, hand bones clustered together. The team argued that the bodies had been covered by sediment quickly, before soft tissue decomposed, and that natural explanations like gravity-driven sediment collapse or bodies washing in with water didn’t match the evidence.
If true, this would make Homo naledi’s burials the earliest known example of deliberate mortuary behavior by any hominin species, and with a brain far smaller than anyone thought necessary for such culturally complex behavior.
Many researchers are not convinced. Critics have pointed to geological, taphonomic (how remains become fossilized), and paleontological evidence suggesting the bones could have accumulated through natural processes: a death trap, water transport, or even carnivore activity. A detailed response published in the Journal of Human Evolution argued that the evidence presented so far is not compelling enough to confirm deliberate burial, and that substantially more analysis is needed to rule out natural explanations for how the bodies ended up where they did.
Fire, Engravings, and Stone Tools
The burial claims were part of a broader set of proposals from Berger’s team suggesting Homo naledi used fire to light the dark cave passages and carved symbolic engravings into the rock walls. These claims have met similar skepticism. Critics argue that the markings haven’t been conclusively shown to be human-made rather than natural, and that the supposed evidence of fire use hasn’t been securely linked to Homo naledi specifically.
One intriguing piece of evidence is a stone object found in the Hill Antechamber, located within 20 millimeters of a cluster of hand bones. The stone is roughly 138 millimeters long, crescent-shaped, and bears what appear to be flake scars and surface markings consistent with use wear. Researchers noted its distinctive shape compared to other rocks in the chamber, raising the possibility it served some function. But the team stopped short of confirming whether the stone was intentionally modified or simply selected by Homo naledi. Its placement near the hand, embedded in the same sediment as the bones, is suggestive but not definitive.
Where It Fits in Human Evolution
Homo naledi complicates the story of human evolution in a productive way. For decades, the general picture was a progression from small-bodied, small-brained Australopithecus to larger-bodied, larger-brained Homo erectus and eventually to Homo sapiens. Homo naledi breaks that pattern. It combined an ancient-looking skull with a modern-looking lower body and lived recently enough to overlap with early modern humans.
Its closest comparison in some ways is Homo floresiensis, the “hobbit” species from Indonesia, which also had a tiny brain and survived until relatively recently. Both species suggest that small-brained human relatives persisted far longer than the traditional model predicted, and that brain size alone doesn’t determine whether a species thrives or goes extinct.
Whether Homo naledi truly buried its dead or used fire remains unresolved. But even setting aside those claims, the species has already reshaped how scientists think about the diversity of human relatives that shared Africa with our ancestors less than 300,000 years ago. The fossil record, it turns out, was far more crowded and far stranger than anyone expected.