Homo Naledi Burials

The field of paleoanthropology was recently shaken by claims that a small-brained human ancestor, Homo naledi, engaged in complex mortuary practices. If confirmed, this discovery in South Africa could rewrite the timeline of human cognitive evolution. It suggests that complex behaviors like burying the dead and making art are not exclusive to humans with large brains.

The Rising Star Cave Discoveries

The focus of this investigation is the Rising Star cave system located in the Cradle of Humankind, a UNESCO World Heritage Site in South Africa. Since 2013, this site has yielded over 1,500 fossil specimens, making it one of the richest fossil sites in Africa. The species at the center of this research is Homo naledi.

This species presents a confusing mix of ancient and modern traits. They walked upright and had hands capable of manipulating tools, yet their shoulders were built for climbing. Most notably, their brain size was approximately 450 to 600 cubic centimeters. This is roughly one-third the size of a modern human brain and comparable to an orange or a chimpanzee’s brain.

Led by National Geographic Explorer in Residence Lee Berger, the research team has spent years navigating the dangerous, narrow chutes of the cave system. In 2023, they released pre-print papers describing evidence suggesting these hominids did not just die in the cave, but were deliberately placed there.

Evidence of Intentional Interment

The primary claim revolves around excavations in the Dinaledi Chamber and the Hill Antechamber. The team described identifying shallow, oval-shaped pits that they argue were dug to contain bodies.

Specific details from the findings include:

• Fetal Positioning: The fossils were found in a curled-up, fetal position. This is a common posture in intentional burials to fit bodies into smaller graves.
• Soil Stratigraphy: Researchers noted that the sediment filling the pits differed from the surrounding cave floor. This implies the dirt was dug out and then put back over the body.
• Associated Artifacts: In one instance, a stone tool-shaped artifact was found near the hand and wrist of a specimen, described as potential grave goods.

These burials are dated to between 200,000 and 300,000 years ago. Before this, the earliest clear evidence of intentional burial belonged to early Homo sapiens and Neanderthals, appearing around 100,000 years ago.

Rock Art and Control of Fire

The claims regarding Homo naledi go beyond burial. The research team also documented engravings on the limestone walls of the cave corridors near the burial sites.

These markings are described as cross-hatchings, geometric shapes, and “hashtag” like symbols. To create these marks, the creator would have had to prepare the surface and apply significant pressure with a tool. The researchers argue that the dates of the sediment covering these engravings overlap with the time Homo naledi occupied the cave.

Furthermore, deep cave navigation requires light. The Dinaledi Chamber is in total darkness, hundreds of feet from the entrance. The team found evidence of:

• Hearths
• Charcoal
• Burnt animal bones
• Soot on the cave ceilings

This suggests that Homo naledi controlled fire and used torches to navigate the complex underground routes to dispose of their dead and create carvings.

Scientific Skepticism and Review

It is vital to note that these findings have sparked intense debate within the scientific community. When Lee Berger and his team released their initial papers and the accompanying Netflix documentary, Unknown: Cave of Bones, the peer review process was still ongoing.

Following the release, independent reviewers and other paleoanthropologists raised significant concerns.

Key points of criticism include:

• Geological Explanations: Critics argue that the “pits” could be natural depressions in the cave floor. Water movement or sediment slumping might have caused the bodies to settle into these shapes, rather than intentional digging.
• Lack of Excavation Data: Some reviewers noted that the initial reports lacked detailed sediment analysis that definitively proved the soil was disturbed by digging tools.
• Dating the Art: While the engravings exist, dating rock art is notoriously difficult. Critics point out that there is no definitive proof connecting the art to Homo naledi. It is possible that modern humans entered the cave thousands of years later and made the marks.

The scientific consensus is currently in a “wait and see” mode. The claims are extraordinary, and in science, extraordinary claims require extraordinary evidence. The team is currently conducting further analysis to address these critiques.

Implications for Human Evolution

If the findings are validated, the implications are profound. For decades, anthropologists believed that “human” behaviors (burial, art, symbolism) were inextricably linked to the evolution of a large brain. The “cerebral rubicon” hypothesis suggested you needed a brain size of at least 800cc to perform complex tasks.

Homo naledi challenges this biological determinism. If a creature with a brain the size of a chimp’s could mourn its dead, navigate dark caves with fire, and create symbols, it suggests that cognitive complexity is not just about brain volume. It may be about neural structure or emotional complexity that does not fossilize.

This shifts the narrative of human evolution from a straight line of getting smarter and bigger-brained to a branching tree where different species developed complex behaviors independently.

Frequently Asked Questions

When was Homo naledi discovered? The first fossils were discovered in the Rising Star cave system in 2013, with the species formally named and described in 2015.

How big was the brain of Homo naledi? Their brain capacity was between 450 and 600 cubic centimeters. For comparison, a modern human brain is roughly 1,350 cubic centimeters.

Did Homo naledi live at the same time as humans? Yes. Homo naledi lived between 236,000 and 335,000 years ago. This means they coexisted in Africa with the ancestors of modern humans (Homo sapiens).

Are the burials confirmed by the entire scientific community? No. While the discovery team is confident, many outside experts remain skeptical. They are calling for more geological data to rule out natural causes for the positioning of the skeletons.