A recent study re-examines evidence from the Rising Star cave system in South Africa, suggesting that an extinct species of small-bodied hominin with a brain size much smaller than that of modern humans may have intentionally buried their dead over 240,000 years ago.
This type of behavior was previously considered to be unique to Homo sapiens. The new discovery, published in eLife, draws on skeletal, geological, and spatial data to argue that deliberate burial is the most plausible explanation for the remains found in the cave, pushing back the date of such behavior to much earlier times than previously expected by scientists.
The discovery of Homo Naledi began in 2013, when paleoanthropologist Lee Berger recruited a team of researchers capable of navigating the extremely narrow passages of the Rising Star cave near Johannesburg, South Africa. Some sections of the cave measure just 20 centimeters across, requiring small-bodied team members to access the deeper chambers. Inside, the team uncovered more than 1,500 bones representing at least 15 individuals of a previously unknown hominin species.
Homo Naledi were less than five feet tall, with a combination of ape-like shoulders, human-like hands and feet, and a brain roughly one-third the size of that of modern humans. Since the discovery, researchers have debated how the remains came to rest in such a difficult-to-reach part of the cave.
In 2015, Berger suggested that Homo Naledi intentionally placed their dead in the cave, a proposal that drew both interest and skepticism. The intentional practice of burying the dead is often viewed as an indicator of modern human activity, reflecting the capacity for symbolic thinking and social bonding. Many experts took aim at Berger's theory, suggesting that the way the fossils were found might be explained by natural events, such as flooding or shifting sediment. Others expressed doubts after Berger made his findings public, which included the creation of a Netflix documentary, and some academics took issue with the limited involvement of outside experts in the initial stages of the study.
The new study, which includes 28 researchers from six countries, aims to address earlier criticisms by systematically designing a minimal cultural-burial hypothesis to test against other possible explanations. The authors conclude that intentional burial remains the most likely scenario based on the available evidence.
The team identified two new clusters of remains in the Dinaledi Subsystem and Hill Antechamber, describing approximately 90 skeletal elements and 51 teeth, including those from juveniles. Notably, several bones were found in anatomical alignment, such as a nearly complete foot and ankle, a partial hand and wrist, and ribs and jaws in sequence. The arrangement of these articulated remains indicates that whole bodies were deliberately positioned within the chamber rather than being dispersed by natural processes.
Sediment analysis provides further support for intentional burial. The chamber deposits indicate dry-cave conditions, with no evidence of water flow that could have naturally moved the bones. The narrow, uphill passages leading to the chamber would have restricted sediment entry, making natural accumulation improbable. The absence of carnivore tooth marks on the bones also suggests that scavengers did not move the remains into the chamber.
In some cases, the burials appear to have been disturbed, possibly by later groups of Homo Naledi displacing earlier ones. The presence of a single stone object, positioned unusually on the chamber floor, remains unexplained and adds another layer of complexity to the findings.
If these actions were intentional, it would mean Homo Naledi practiced mortuary behavior more than 100,000 years before the earliest Homo sapiens burials. This supports the main argument that traits linked to ritual and planning, once considered exclusive to modern humans, could have developed much earlier in hominin evolution, despite differences in brain size.
Similar debates have surrounded Neanderthal burial sites, such as the well-known 'flower burial' at Shanidar Cave in Iraq, which has prompted ongoing discussion about intentionality and symbolism. Other discoveries, including Neanderthal cave art, the use of adhesives and tools, and evidence for seafaring by Homo floresiensis, have already challenged the distinction between 'archaic' and 'modern' cognition. The findings from Homo Naledi add further complexity to this picture.
Although the fossil record from Rising Star is extensive, there is little evidence about the daily life of Homo Naledi. The cave contains no signs of habitation, such as hearths, tools, or food remains, but only the bodies that appear to have been placed there after death. The repeated use of a challenging and hazardous space for this purpose suggests motivations beyond simple disposal. Whether driven by emotional, symbolic, or practical reasons, the behavior indicates that cognitive complexity may not be directly linked to brain size.
The authors conclude, 'Cultural burial best fits the combined lines of evidence.' If confirmed, this finding broadens our view of hominin history, suggesting symbolic and ritual practices may extend beyond Homo sapiens and point towards a gradual emergence of human behaviors.