Homo Naledi Burials: The Paleoanthropology Feud

In June 2023, a massive controversy erupted in the scientific community regarding the origins of human culture. A team of researchers led by paleoanthropologist Lee Berger announced that Homo naledi, an extinct human relative with a brain the size of an orange, had deliberately buried its dead and carved symbols onto cave walls. These claims challenged the long-held belief that only large-brained humans were capable of such complex behavior. However, the announcement triggered an immediate and intense backlash from other experts, leading to one of the most public academic feuds in recent history.

The Bombshell Claims

The controversy centers on the Rising Star Cave system in South Africa. This is where Lee Berger, a National Geographic Explorer in Residence, and his team found remains of Homo naledi. In a series of pre-print papers released in 2023, the team argued that they found evidence of three deliberate burials within the cave.

The specifics of the claim were groundbreaking:

• The Dates: The remains are dated to between 241,000 and 335,000 years ago.
• The Action: The team asserted that holes were dug through the cave floor, bodies were placed in a curled-up fetal position, and the holes were then filled with soil.
• The Tool: A stone tool-shaped object was allegedly found near the hand of one of the skeletons.
• The Engravings: The team also identified cross-hatchings, or “hashtag” markings, on the walls near the bodies. They claimed these were intentional designs made by H. naledi.

If these claims are true, it means a species with a brain one-third the size of ours invented mortuary practices and art more than 100,000 years before Homo sapiens is thought to have done so.

The Scientific Backlash

The “feud” began not just because of the claims, but because of how they were released. The team announced their findings through a global media campaign, including a Netflix documentary titled Unknown: Cave of Bones, before the scientific papers had completed the peer review process.

When the papers were reviewed by the journal eLife, the reception was harsh. eLife uses a unique transparent review process where peer reviews are published alongside the article. The four anonymous reviewers, experts in biological anthropology and archaeology, unanimously found the evidence “inadequate” and “incomplete.”

The Argument Against Burials

Critics pointed out several major flaws in the “burial” hypothesis. The primary issue was geological. To prove a burial, you must prove a hole was dug. This requires showing a clear cut in the soil layers, known as stratigraphy.

Reviewers noted that Berger’s team failed to provide high-resolution analysis of the sediment. Without this, there is no way to distinguish a dug hole from a natural depression in the cave floor. Water flow, gravity, or the natural slumping of the cave floor could have caused the bodies to end up in low spots that were later covered by dust and mud.

Experts like María Martinón-Torres, a paleoanthropologist at the National Research Center on Human Evolution in Spain, publicly critiqued the findings. She noted that finding bones in an anatomical position (where the joints are still connected) does not automatically mean they were buried. It simply means the body decomposed quickly in a protected environment.

The Problem with the “Art”

The claims regarding the rock engravings faced even stiffer skepticism. The team described cross-hatched lines etched into dolomite rock. However, critics argued that the team did not date the engravings. There is currently no evidence linking the marks to the time period when Homo naledi occupied the cave.

Furthermore, peer reviewers pointed out that the Rising Star Cave is subject to natural weathering. Dolomite rock can fracture naturally in patterns that look like geometric shapes. Without microscopic analysis to prove a tool was used, or dating techniques to establish the age of the patina (the film on the rock surface), the markings could be modern graffiti or natural geological features.

Why the "Small Brain" Factor Matters

The intensity of this debate stems from what Homo naledi represents. For decades, science operated on the assumption that “encaphalization” (getting a bigger brain) was the prerequisite for complex culture. Big brains require massive amounts of energy. The evolutionary payoff for that energy cost is supposed to be advanced cognitive abilities, such as mourning the dead or creating symbols.

Homo naledi disrupts this timeline. They walked upright and had human-like hands, but their skulls were tiny (roughly 450 to 600 cubic centimeters).

If Berger is right, the link between brain size and cognitive complexity is broken. It would suggest that emotional depth and symbolic thought are not unique to big-brained humans. If the critics are right, this represents a case of “science by press release,” where media hype outpaced the actual data.

The Current State of the Debate

As of late 2023 and early 2024, the revised versions of the papers are still under scrutiny. The team has promised to conduct further sediment analysis to address the reviewers’ concerns. They need to use techniques like micromorphology (studying soil under a microscope) to prove the sediment was disturbed by digging tools rather than natural water flow.

The scientific community remains divided but skeptical. While many admire the sheer physical difficulty of excavating the Rising Star Cave (which requires squeezing through an 18-centimeter chute), the consensus is that extraordinary claims require extraordinary evidence. Currently, the evidence for intentional burial is considered weak by the broader anthropological establishment.

Frequently Asked Questions

Did Homo naledi definitely bury their dead? No. While the discovery team claims they did, independent peer reviewers have rejected the current evidence as inconclusive. Most experts believe the bodies may have accumulated naturally or fell into depressions in the cave floor.

How big was Homo naledi? They were relatively short and slender. They stood about 4 feet 9 inches (144 cm) tall and weighed between 88 and 123 pounds (40 to 56 kg).

What is the “Brain of an Orange” comparison? This refers to the volume of the Homo naledi brain. It is approximately 450 to 600 cubic centimeters, which is similar to a large orange or a grapefruit. This is roughly one-third the size of a modern human brain.

Where is the Rising Star Cave? The cave system is located in the Cradle of Humankind World Heritage Site in South Africa, about 30 miles northwest of Johannesburg.

Why is the Netflix documentary controversial? The documentary presented the burials and rock art as proven facts. However, at the time of release, the scientific papers supporting these claims had not yet passed peer review. Many scientists felt this misled the public about what was actually known.