A Cave Full of Strangers, and Not One of Them Is Male

Deep in the Rising Star cave system in South Africa, researchers have been pulling Homo naledi fossils out of the dark for over a decade. Twenty individuals. Hundreds of bone fragments. One conspicuous absence: not a single male among them.

The cave system has yielded more than 1,500 fossils and 150 hominin teeth, excavated beginning in 2013 by an all-female team of "underground astronauts." A study now published in Cell reports that scientists found no signs of any biological males within the group of Homo naledi remains tested.

The method is worth understanding. Tooth enamel contains a protein called amelogenin, and the X and Y chromosomes produce different versions of it; scientists can test for biological sex based on which version is present in a fossil. Out of 20 individuals, the Y chromosome marker was definitively absent in 19 samples and likely absent in the one outlier. That held even for a fossil previously classified as male — it also tested negative for the Y-linked marker.

The unusual skew may mean that only certain individuals ended up in this part of the cave, or that Homo naledi lacked the gene that produces the male marker altogether. But the leading interpretation is more culturally arresting. The study's lead researcher has said "the most likely explanation for the observed absence of an Amelogenin-Y marker in these individuals is that we are seeing a sex-bias in mortuary practice, a practice until now only observed in contemporary human cultures."

Outside researchers remain cautious. Drawing cultural conclusions from biological data is difficult, especially with limited or unique context. One outside researcher observed that the species sits precisely at the intersection where biology and cultural interpretation become impossible to separate.

Homo naledi lived between 335,000 and 241,000 years ago, with a brain roughly one-third the size of ours. The cave, apparently, knew something we did not.

Read the full story at National Geographic, June 24, 2026

Hot Take: The species had a brain the size of an orange and may have been sorting its dead by sex before Homo sapiens had gotten around to inventing the concept of a funeral. The question of what counts as "culture" just got considerably harder to answer, and the people who thought they had that answer are going to need a moment.