Ancient All-Female Site
New Proteomics Study Confirms All Homo naledi Fossils From Rising Star are Female
Key Points
The study used a minimally destructive acid-etching protocol to extract enamel peptides from fossil teeth and sequence ancient proteins, with amino-acid analysis used to confirm the samples’ antiquity and rule out modern contamination.
The 23 teeth studied come from Rising Star’s Dinaledi Chamber and represent at least 20 individuals, reporting across a range of ages to build a cross-section of the population.
Some outlets have framed the findings as potentially the oldest known sex-specific burial site by a non-human species, given the apparent absence of male markers across the sample.
"The chance of having sampled 20 individuals and they are all from one sex is quite literally one in a million"—a line highlighting how unlikely the all-female pattern would be by chance alone.
There is ongoing debate in the field about the burial interpretation, with some researchers expressing skepticism or calling for caution in drawing social-behavior conclusions from the pattern of remains.
Every skeleton ever found in the Dinaledi Chamber of South Africa's Rising Star cave is female — and the odds of that happening by chance are about one in a million. A new study published June 24, 2026, in the journal Cell used ancient proteins extracted from 23 teeth to confirm the absence of any male biological marker across at least 20 individuals, spanning infants to older adults. Live Science reported the finding as one of the most surprising results in human origins research in years.
The species is Homo naledi, a small-brained hominin that lived roughly 241,000 to 335,000 years ago. The all-female result adds a stunning new layer to an already strange fossil site — and pushes scientists to ask whether this cave was used for something deliberate, structured, and social. CNN described the discovery as one that has "rocked the field of human origins."
Ancient Tooth Proteins Reveal a Hidden Sex Signature
The research team used a technique called paleoproteomics — the study of ancient proteins — to read biological sex from tooth enamel. Tooth enamel preserves proteins far longer than DNA, especially in warm climates like South Africa. The key protein is called Amelogenin. It appears in two forms: one coded by the X chromosome, one by the Y. Only males carry the Y version, called AMELY. Researchers found AMELY in zero of the 23 teeth tested.
Lead author Dr. Palesa Madupe said the team ran the data twice to make sure. "Two labs ran this data," she told CNN. "We ran it through twice because we didn't want it to be an internal error." The team also used a minimally destructive acid-etching method, so the rare fossils were not significantly damaged. That technique is now being hailed as a new standard for fossil sex analysis.
One in a Million: The Statistical Case for Something Deliberate
If males and females entered the cave in equal numbers by random chance, the probability of drawing 20 females in a row is less than one in a million — specifically about 1 in 1,048,576. That number comes from the research team itself. Lead researcher Prof. Lee Berger put it plainly: "The chance of having sampled 20 individuals and they are all from one sex is quite literally one in a million," according to Live Science.
That statistical weight leads the authors to suggest the Dinaledi Chamber may be the oldest known sex-specific burial site in the fossil record — created not by humans, but by a non-human species with a brain roughly the size of a chimpanzee's. The age range of the remains, from infants to the elderly, rules out the idea that only one type of individual — say, young adults — ended up there. The pattern cuts across all life stages.
Skeptics Push Back on the Burial Interpretation
Not everyone is ready to call Dinaledi a prehistoric female cemetery. Some researchers warn that the AMELY protein could have degraded or been lost — a problem called a "false negative." Dr. Carles Lalueza-Fox, a molecular biologist at the University of Barcelona, urged caution. He noted that in some isolated populations, the AMELY gene can disappear through a process called a founder effect — meaning these individuals might include biological males who simply lacked the marker. Live Science flagged his concerns.
Other scientists point to taphonomy — the way bones move and settle over time. Could water or cave geology have sorted remains by size, making smaller female skeletons more likely to accumulate in one spot? Some researchers published in peer-reviewed journals as recently as April 2025 found no geological proof of excavated burial pits at the site, Phys.org noted. The debate over what Homo naledi actually did in that cave is far from settled.
What It Means for Human Origins and Brain Size
Homo naledi had a brain of just 450–610 cubic centimeters — barely larger than a chimpanzee's. Modern humans average about 1,350cc. For decades, scientists assumed that complex social behavior required a large brain. If Homo naledi really did organize its dead by sex, that assumption collapses. Co-author Prof. John Hawks called the pattern a "complex cultural signal," according to CNN.
The bigger question now: where are the males? Senior author Dr. Enrico Cappellini asked it directly — "If the H. naledi individuals are all females, then where are the males?" Researchers are now looking at nearby chambers in the Rising Star system, including the Lesedi Chamber, for signs of a corresponding male assemblage. The answer could reshape how scientists think about social structure in our ancient relatives. Live Science called it "a weird result from an already weird hominin."
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