Questions about Homo naledi rise to the surface
Professors at odds over how the species in world-famous cave discovery treated death
PROFESSOR Francis Thackeray wants to live to 100.
Only then might he have the proof he needs that Homo naledi — our celebrated ancestor discovered a year ago at the Rising Star cave system in Gauteng to much global fanfare — did not in fact bury their dead.
The maverick professor from the University of the Witwatersrand — who made headlines around the world when he painstakingly proved that Shakespeare was a stoner by analysing the contents of pipes found in his garden — has now laid out some bones in the
There is no debris from a collapse and zero evidence one occurred
Cradle of Mankind (very close to Rising Star) to prove his point.
The problem is, the results will only be available in 30 years’ time when Thackeray himself might be no more than a skeleton.
Last year, when Homo naledi was discovered and described in an astonishing research paper that involved more than 45 authors, Professor Lee Berger — also from Wits — and his team captured the imagination of the world.
They said Homo naledi must have buried their dead, given the nature of the complicated, dark and narrow route along which the bodies must have been taken to end up where they did: in the remote Dinaledi chamber about 30m below the surface.
The only other species to deliberately dispose of their dead is us, Homo sapiens.
A few months later, Thackeray claimed that black spots of manganese dioxide on the bones were caused by lichen, which requires light to grow.
If there was evidence of exposure to light, surely this meant there was another entrance?
And if there was another entrance, surely this proved that the 15 Homo naledi skeletons were not the buried dead. They had likely made their way there as living beings via another entrance.
Berger and his team of experts have now hit back, publishing a rebuttal in the South African Journal of Science in which they say Thackeray ignored vast amounts of evidence. THEM BONES: Above, Professor Lee Berger, who believes that Homo naledi, left — the fossils of which were discovered near Johannesburg — buried their dead. Below, Professor Francis Thackeray. Left, a Homo naledi skull
But Thackeray, too, is like a dog with a, well, bone.
“To study the growth and development of lichen, I have laid down a set of modern bones of animals extending from the entrance of a cave, down into semi-darkness, and then into total darkness at the back of the cave, which is situated in the Cradle of Humankind,” he said.
His plan is to monitor the growth of lichen on the modern bones for a 30-year period, beginning this year, to analyse the role light plays.
“I hope to be alive in 30 years’ time,” Thackeray said. “It should be remembered that in science, answers are not always obtained within short periods such as a year or two. I will be close to 100 so please ask me then about my responses!”
Berger is convinced Thackeray’s hypothesis “ignored evidence that was published, tested and readily available.” He said Thackeray simply homed in on the black spots.
From there, argued Berger, Thackeray said there was another entrance and built a case for a collapse rather than a deliberate disposal of the dead.
He said Thackeray’s hypothesis was full of holes.
Firstly, he said, “there are many ways in which manganese forms in the absence of light. In fact, Thackeray’s idea of lichen causing manganese formation is his own, and has never been scientifically tested.
“Lichen might cause the black spots, but his argument is based on an assumption that might be wrong.”
Also, said Berger, the black spots appeared on “all sides of the bones” yet Thackeray ignored this fact and failed to “explain how lichen would grow on the underside of bones” if it was caused by light.
Then there is the issue of the disastrous “collapse” that led to Homo naledi being buried.
“There is no debris from a collapse and simply zero evidence one ever occurred,” and also, “the bodies did not all come in at once”, which means a mass death did not occur.
He added that Thackeray’s argument that the presence of invertebrates such as snails also proved there was light is “simply ignorant of the vast scientific literature of snails and other invertebrates living and thriving in complete darkness”.
It might take 30 years for the bones laid out in the Cradle of Mankind to give some answers, but during that time, there is certain to be more intellectual sparring between these two titans from the halls of academia.
I will be close to 100 so please ask me then about my responses!