Evidence for cultural mortuary practices of Homo naledi
Homo naledi is a small-bodied, small-brained human species described in 2013 from fossils recovered from the Dinaledi Chamber in the Rising Star cave system, South Africa. The initial finds are thought to represent at least 15 individuals. Since then, additional remains have been found in the Dinaledi and other chambers of the cave system, ranging from infants to older adults. Some of the remains have been dated to 335,000–236,000 years ago, suggesting a possible overlap with the earliest representatives of Homo sapiens.
The Dinaledi Chamber lies 30 m (100 ft) below the surface and 80 m (260 ft) in a straight line from the nearest entrance. Reaching it requires negotiating a complicated set of passages and fractures for 120 m (395 ft) and passing through a narrow access point known as Superman’s Crawl, so called because cavers can only pass through it by extending one arm in front of themselves like Superman in flight. Superman’s Crawl leads into a large antechamber known as the Dragon’s Back Chamber. Cavers must then make a 15 m (50 ft) climb up the side of the Dragon’s Back, a sharp-edged dolomite block that has dislodged from the roof. From there, they must descend the 12 m (39 ft) vertical drop now known as the Chute to reach the Hill Antechamber (U.W. 107), which leads via a passageway into the Dinaledi Chamber proper. The Chute is in places as narrow as 0.2 m (7.9 in). The main passage of the Dinaledi Chamber is 10 m (33 ft) long, but its minimum width is just 0.25–0.5 m (10 in – 1 ft 8 in).
Homo naledi individuals were smaller than modern people. They ranged in height from 1.40 cm to 1.65 m (4 ft 7 in to 5 ft 5 in), but they were only slightly smaller than the “skinny and preferably small” team members selected by anthropologist Lee Berger for the recovery of the fossils. How the remains of such a large number of individuals got there in the first place has been the subject of considerable debate.
There is a near-absence of non-hominin fossils in Dinaledi Chamber – yet they are abundant in Dragon’s Back. This rules out the remains having been swept into Dinaledi Chamber by a flash flood, as it would have left a mixture of hominin and non-hominin remains in both chambers. Carnivores are also unlikely: even if there had been a carnivore that preyed exclusively on Homo naledi, why would it drag its prey into such an inaccessible location? In any case, none of the bones shows any signs of gnawing. The possibility that there might once have been another, easier route into the chamber has also been ruled out.
This leaves only the possibility that the remains were deliberately placed in these chambers by fellow group members, as part of a mortuary ritual. If so, it would confirm suggestions that such behaviours have an ancient origin and are not restricted to Homo sapiens and possibly Neanderthals, with far larger brains than Homo naledi.
The deliberate placement theory gained strength with suggestions that all the Homo naledi individuals recovered from Rising Star were the same sex. The individuals show a high degree of morphological homogeneity, including dental variation – suggesting a single sex.
To date, no ancient DNA has been recovered from any of the Rising Star individuals. However, palaeoproteomic analysis is a relatively new technique that enables genetic information to be derived from ancient, preserved proteins. It can distinguish between males and females by identifying sex-chromosome-linked variants of the protein amelogenin preserved in ancient tooth enamel. The genetic blueprint for dental enamel protein is located on the sex chromosomes, and so males and females will present slightly different chemical signatures. The peptides AMELX and AMELY are associated with amelogenin; AMELX is expressed in both sexes, whereas AMELY is expressed only in males, at a rate of roughly 10 per cent that of AMELX.
Researchers extracted dental proteins from 23 Homo naledi individuals. The analysis failed to identify any trace of ALELY, suggesting that the individuals analysed were all female.
While these results are not conclusive, the probability of a random accumulation of 23 females is vanishingly small, and would strongly suggest cultural mortuary practices.
Reference
Madupe, P. P. et al. Proteomic analysis of dental enamel from 20 Homo naledi individuals shows no male markers. Cell 189, 4415-4424.e11 (2026).