The question of whether Homo naledi, a hominin species that existed between 335,000 and 245,000 years ago, engaged in complex ritualistic practices such as burying its dead has sparked considerable debate. This species, despite possessing a brain approximately one-third the size of a modern human’s, is theorized by some researchers to have developed such sophisticated behaviors. The initial assertion, put forth by a team led by Lee Berger from the University of the Witwatersrand, suggested that H. naledi intentionally deposited its deceased in a deep, difficult-to-access cave chamber. This proposition was met with skepticism from anonymous reviewers, but Berger and his colleagues remained committed to their findings.
An updated version of their study, released earlier this year, provided a more in-depth analysis of the evidence gathered from the Rising Star cave system in South Africa. This comprehensive approach appears to have swayed some initial critics, with one of the original reviewers reportedly changing their stance. “You rarely see that in peer review,” commented John Hawks, a member of Berger’s team at the University of Wisconsin-Madison, highlighting the unusual nature of this scientific reassessment.
Despite this progress, many other researchers remain unconvinced. Paul Pettitt from Durham University in the UK stated, “I’m just not convinced by any of it.” To understand this skepticism, it is crucial to examine how other ancient hominins interacted with their dead. Such an exploration can shed light on the earliest occurrences of burial practices, their temporal origins, and what these actions might reveal about the cognitive abilities and motivations of these ancient beings. Furthermore, a thorough consideration of this topic is essential because, if H. naledi indeed practiced burial, it would necessitate a fundamental reevaluation of our current understanding of early hominin cognition and behavior.
The Pit of Bones: A Precursor to Funerary Behavior?
The Sima de los Huesos site in northern Spain shares notable similarities with the Rising Star system. This location, translated as the “pit of bones,” has yielded the remains of 29 hominins, believed to be an ancestor of Neanderthals. These individuals were found at the bottom of a vertical shaft within a cave. The prevailing scientific consensus is that the Sima hominins, who lived between 430,000 and 300,000 years ago, died elsewhere, and their bodies were subsequently deposited into the pit. If this interpretation is accurate, it represents the oldest clear evidence to date of some form of funerary behavior.
While this early date might seem surprising, it aligns with observed behaviors in related species. Chimpanzees, for instance, exhibit interest in deceased group members, engaging in grooming and cleaning activities. “If we have chimpanzees behaving this way, then we might expect similar behavior deep in our evolutionary past,” noted Pettitt. María Martinón-Torres of the National Human Evolution Research Centre (CENIEH) in Spain suggests that the funerary practices at Sima de los Huesos appear more sophisticated than those observed in chimpanzees, indicating a deliberate choice of location for the deceased. Additionally, the excavation uncovered a stone hand axe, which has been interpreted by some as a funerary offering. However, Pettitt offers a more pragmatic explanation, suggesting it could have been a tool carried in a pouch by one of the individuals found there.
The potential evolutionary benefits of such elaborate treatment of the dead are a subject of ongoing inquiry. Pettitt proposed in a 2023 paper that as hominins developed increased cognitive abilities, reflected in brain size, they likely became aware of their own mortality. Complex funerary behavior may have emerged as a mechanism to alleviate personal anxiety surrounding death by fostering community cohesion during times of loss. This theory gains traction when considering the average brain size of the Sima hominins, which was approximately 1237 cubic centimeters, only about 100 cubic centimeters less than that of modern humans.
Conversely, some researchers propose a more somber interpretation of the Sima de los Huesos findings. Mary Stiner from the University of Arizona highlights that a significant portion of the skeletons belong to adolescents and young adults, an age group characterized by risk-taking behavior and vulnerability due to limited experience. Signs of violent death on some of the bones have led Stiner to hypothesize that these individuals may have left their family groups, ventured into hostile territories, and met a violent end, with their bodies disposed of in the pit to conceal the crime. However, Pettitt points out the improbability of such a large number of adolescents making the same mistakes and meeting a similar fate.
The exact interpretation of the Sima de los Huesos site remains elusive. Further evidence may emerge from ongoing research. Since 2021, a project known as DEATHREVOL, led by Nohemi Sala from CENIEH, has been investigating the archaeological record of funerary behavior. Sala’s research suggests the existence of other ancient European sites that may hold similar evidence, although these locations have not yet been publicly disclosed. “There are four or five candidates to explore these patterns,” she stated, indicating that Sima de los Huesos might not be an isolated phenomenon.
Neanderthal Burials: Glimpses into Their Relationship with the Deceased
Neanderthals, descendants of hominins like those found at Sima de los Huesos, exhibited distinct practices regarding the treatment of the dead. The Shanidar cave in northern Iraq, excavated since the mid-20th century, has revealed the remains of at least 10 Neanderthals, with the oldest dating back approximately 75,000 years. This makes it one of the most ancient known Neanderthal burial sites.
A notable discovery at Shanidar involved a set of remains around which pollen was found, suggesting the individual was buried with flowers. This finding in the late 20th century was instrumental in recognizing Neanderthals as possessing a degree of shared humanity. While contemporary archaeologists generally no longer subscribe to the “flower burial” theory, recent excavations at Shanidar have proposed an alternative explanation for the pollen. Chris Hunt of Liverpool John Moores University in the UK and his colleagues suggest that the body may have been placed in the ground and then covered with brushwood rather than soil. They note that pollen from certain spiky plants found around the skeleton could have been used to deter scavengers.
Despite the reinterpretation of the flower burial, the Shanidar findings remain significant. The remains of a man who survived severe facial, shoulder, and arm injuries suggest that Neanderthals offered care and value to individuals. Stiner postulates that this care extended beyond mere utility for survival, implying that the loss of an individual with a unique personality would have been mourned, thus providing a new motivation for funerary behavior. “These societies were bound by love and affection,” Stiner remarked.
Furthermore, five skeletons at Shanidar were found buried in the same location, in proximity to a distinctive 2-meter-high rock formation within the cave, over a period spanning decades to millennia. Hunt and his colleagues interpret this as a potential indication that Neanderthals associated meaning with landmarks in their environment. A more speculative idea suggests that these burials might have served to legitimize territorial claims. Emma Pomeroy of the University of Cambridge, who participated in recent Shanidar excavations, finds the possibility of Neanderthals having a similar relationship with the landscape an intriguing area for consideration.
Several questions regarding Neanderthal burial practices persist. A significant one is why only a select number of Neanderthals in the vicinity of Shanidar were interred in the cave. Hawks notes that extensive burials would be expected if this were a widespread practice. Evidence from other sites suggests alternative funerary treatments, including ritual cannibalism, but the reasons for the limited interments at Shanidar remain unclear. Another point of discussion is whether Neanderthals developed burial independently or acquired this practice from Homo sapiens, whom they encountered around the time of the Shanidar burials.
Early Homo sapiens and the Emergence of Grave Goods
Our own species, Homo sapiens, began burying its dead approximately 120,000 to 100,000 years ago. Some early H. sapiens burials appear to distinguish themselves from Neanderthal practices through the inclusion of grave goods. For example, a burial in Qafzeh cave in Israel contained red deer antlers clasped to the individual’s chest. However, an alternative interpretation suggests the antlers might have been used for digging the grave, making their presence a matter of coincidence, according to Pettitt. The rarity of human burials before 28,000 years ago makes it difficult to ascertain the prevalence of early grave goods or their precise significance, though in later periods, they are generally understood to reflect the deceased’s status and occupation.
The Graves of Young Children
Despite their scarcity, early human burials offer intriguing insights. In 2021, researchers, including Martinón-Torres and Michael Petraglia (now at Griffith University, Australia), described the excavation of a 78,000-year-old burial of a toddler, named Mtoto, at Panga ya Saidi cave in Kenya. Mtoto represents the earliest of three potential H. sapiens burials in Africa, dating between 78,000 and 68,000 years ago, all involving young children.
The prevalence of childhood mortality in these early communities was likely high. Petraglia suggests that this is a reasonable assumption, given similar rates in hunter-gatherer societies. Martinón-Torres posits that particularly painful childhood deaths might have motivated early communities to commemorate these children with burial, a then-unusual funerary ritual. Pettitt’s research distinguishes between “good deaths,” typically occurring in old age, and “bad deaths,” which are unexpected and often affect children. He proposes that the latter may have spurred the development of special funerary rites, such as the burial of Mtoto.
The location of the Panga ya Saidi cave, a site of human habitation for extended periods, offers another clue to the mindset of these Stone Age people. The decision to inter Mtoto’s body within close proximity to the community’s living space suggests an emotional connection. Martinón-Torres explains that burying a loved one near the living space can help maintain a close bond, as the desire is not for them to be completely separated. Placing them in an accessible location facilitates continued connection.
Revisiting the Homo naledi Burial Hypothesis
The findings at various archaeological sites offer points of comparison with the Homo naledi burial hypothesis. The act of depositing the dead deep within a cave, as suggested for H. naledi, echoes the practices at Sima de los Huesos thousands of years earlier. The idea that H. naledi repeatedly returned to the same site for interments can be compared to the situation at Shanidar cave. Furthermore, the discovery of a crescent-shaped stone near the fossilized hand of one H. naledi skeleton, possibly a grave good, bears resemblance to behaviors observed at sites like Qafzeh.
However, significant challenges remain for the burial hypothesis concerning H. naledi. The most substantial obstacle is the small size of their brain, averaging only 513 cubic centimeters. This raises doubts about whether individuals of such cognitive capacity could have been aware of their own mortality and developed elaborate funerary rituals to process this realization. There is also no current evidence suggesting that H. naledi cared for its sick, a potential indicator of valuing individuals and mourning their deaths. While young individuals are overrepresented in the Rising Star cave collections, potentially aligning with Pettitt’s “bad death” concept, the chamber where the bones were found is not easily accessible, hindering the possibility of the living maintaining a connection with the deceased. “It’s quite anomalous, but also fascinating,” commented Stiner.
Two main interpretations can be offered for this puzzle. The first involves seeking non-burial explanations for the accumulation of H. naledi skeletons. For instance, a 2021 report detailed the discovery of 30 baboon remains, nine of which were mummified, in a South African cave chamber. It appears the primates frequented the chamber as a sleeping site over many years, with some dying there and their bodies gradually accumulating. Pomeroy suggested that H. naledi might have utilized Rising Star in a similar fashion.
A more revolutionary alternative is to question whether our current understanding of how and why hominins developed funerary traditions needs revision. Berger posits that spirituality, self-awareness, and mortality could have emerged independently multiple times. Hawks points to the analysis of H. naledi skeletons, which suggests an extended childhood similar to our own. He believes this extended period of development might have enabled them to integrate into social groups in a non-sexually competitive manner and potentially encouraged the development of funerary customs to help youngsters understand the loss of group members. “We have funerals to explain to kids what just happened,” Hawks explained.
Gathering definitive evidence for the burial hypothesis presents considerable difficulty. Unlike modern cemeteries, Stone Age graves were often shallow depressions in the floor. If hominins returned to add more interments, earlier graves could be disturbed, resulting in a jumble of bones that is hard to interpret as distinct burials, as Hawks noted. “They’re not 6 feet under in well-constructed holes,” he remarked.
The researchers leading the investigation, including Berger and Hawks, express optimism due to the presence of substantial untouched material within the Rising Star cave system. Future excavations could bolster their burial hypothesis. Should they succeed in presenting compelling evidence, they may find a receptive audience. As observed, ancient burial sites are often open to interpretation, conclusions remain provisional, and many archaeologists working at these sites welcome new discoveries that challenge existing notions about the prehistory of funerary behavior.
“It’s sometimes suggested that the scientific community just doesn’t want to believe that a small-brained hominin would be capable of symbolic treatment of the dead,” said Pomeroy. “That couldn’t be further from the truth. We’d be so excited – if there was good evidence.”