They Buried Their Dead 100K Years Before Homo Sapiens

Just two hominin species are thought to have intentionally buried their dead: Neanderthals and modern humans. That idea has been floundering over the last decade, however, with the discovery of Homo naledi, an archaic human species that appears to have buried its dead deep inside South Africa's Rising Star cave system at least 100,000 years before the earliest evidence of modern humans doing the same, per National Geographic. Now, in three studies, researchers lay out the best evidence yet that Homo naledi engaged in this and other complex behaviors between 335,000 and 241,000 years ago, despite having a brain roughly a third of the size of modern humans. Indeed, they argue the species shows brain structure to be far more important to cognitive complexity than brain size.

Skeptics have long suggested that water, animals, or modern humans moved the bodies of Homo naledi—a smaller, shorter, and thinner species than Homo sapiens—into the cave system through tiny tunnels. But researchers say they've found no evidence of those scenarios, or of Homo sapiens using the cave system at all. And in the first new study, they describe finding curled bodies of Homo naledi in pits that look to have been dug into the cave floor and refilled with soil, per Nat Geo. Some skeptics still believe water washed the bones into natural depressions, per the New York Times. But lead paleoanthropologist Dr. Lee Berger dismisses that suggestion, describing "a whole body that was covered in dirt and then decayed within the grave itself," per CNN.

Researchers say one grave contains a tool-shaped rock, which might've been used to make geometric carvings on dolomite walls in another cave section under the light of controlled fires, evidence of which is found throughout the chambers. Though the engravings, described in the second study, haven't been precisely dated, researchers conclude Homo naledi are responsible. In the third study, researchers argue the discoveries upend traditional thinking about complex behaviors and the brain. Essentially, "we need to rethink the timing of fire use, of meaning-making, and of the burial of the dead in hominin history," says study author Agustin Fuentes, per CNN. The studies, released as preprints, will undergo peer review before publication in the journal eLife, per the Times. (More discoveries stories.)