Beware of Netflix documentaries

Craig Shearer - 20 November 2023

I’ve recently become aware of a controversy surrounding the discovery of Homo naledi, which was the subject of a Netflix documentary film: Unknown: Cave of Bones

The documentary film is about the discovery of the early human relative in a system of caves, known as the Rising Star caves in South Africa, in a site known as the Cradle of Humankind. A recreational caver discovered a pair of chambers in the cave system back in 2013, after following a narrow 12 metre long chute. The floor of the chamber was littered with fossil bones.

In late 2013, Lee Berger, who is a scientist at the University of Witwatersrand, in South Africa, and also affiliated with the National Geographic Society, began a scientific exploration of the system.

This led to the discovery of Homo naledi, an extinct hominin species, dating to the Middle Pleistocene - being between 236 and 335 thousand years ago. Many bone fragments were found, amounting to at least 15 different individuals.

There are many interesting questions about the find, one of which is that the brain sizes of the individuals have been estimated to be only around a maximum of 600 cc, compared to modern humans (Homo sapiens) having an average capacity of 1350 cc.

What’s interesting about all of this is that it’s thought that burying the dead is something that is related to intelligence, and whether a species with such a small brain size could have done this. There’s also claimed evidence of fire, and of cave art, and the implication that it was H.naledi doing it.

Additionally, access to the cave system is extremely difficult - so how could all these bodies have arrived there. The implication is that they were placed there by grieving relatives. Though perhaps in times past there was a different way to access the chambers that has now become closed off.

Anyway, there is a lot of scientific controversy around this and how it’s been publicised in the media and on social media. As I understand it, the initial publication went into a journal without being peer-reviewed first, and there’s a lot of potentially dodgy stuff around this.

It makes me feel that the Netflix documentary has given this topic an air of authenticity that is perhaps, at this stage, undeserved. It certainly makes claims for completely rewriting the textbooks on human evolution. (And, my feeling is that it probably plays well with creationists.)

Anyway, for a deeper dive on this, there’s a pretty good YouTube video

More detail about the cave and the issues with the claims

I guess it is a good warning that information presented in a highly polished documentary doesn’t make it scientifically true or above skeptical suspicion. There are plenty of documentaries on streaming platforms, and I wonder whether some of them might be going down the path of The History Channel, which infamously now promotes various pseudoscience content such as ancient aliens and UFOs.