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| Engravings on a wall in the Rising Star cave in South Africa. Researchers claim a small-brained relative of humans created the marks, Homo naledi, more than 240,000 years ago. Berger et al. (2023b) |
In 2015, scientists discovered more than 1,500 fossils of an ancient hominin species called Homo naledi, which had never been seen before. After years of analysing the surfaces and sediments of the elaborate underground cave, the same team makes another splashy announcement: Homo naledi buried their dead in graves and lit fires to illuminate their way down the cave. Lee Berger, a paleoanthropologist at the University of Witwatersrand in Johannesburg, said that the discovery that a small-brained hominin did such humanlike things was profound, as it suggests that big brains are not essential for sophisticated kinds of thinking, such as making symbols, and cooperating on dangerous expeditions or even recognising death. This is the ‘Star Trek’ moment, he said, as you go out, you meet a species it’s not human, but it’s equally complex to humans. The Homo naledi remains were discovered in 2013 by two South African spelunkers exploring the Rising Star cave, which extends for miles underground.
Dr Berger organised an expedition into the complex system of chambers and tunnels, which extends for miles underground, and the journal eLife will release three papers detailing the evidence. Dr Berger will describe the findings at a scientific meeting on Monday, and the journal eLife will release three doc-articles detailing the proof. The Homo naledi remains were discovered in 2013 by two South African spelunkers exploring the Rising Star cave, which extends for miles underground. Dr Berger will describe the findings at a scientific meeting on Monday, and the journal eLife will release three papers detailing the evidence. The Homo naledi remains were discovered in 2013 by two South African spelunkers exploring the Rising Star cave, which extends for miles underground.
The researchers found a wealth of bones from at least 27 individuals in a cave. They suggested that Homo naledi brought the bodies there deliberately but left them on the cave floor rather than burying them, act archaeologists call “funerary caching.” However, as they dug up more sediment in 2018, they observed that two fairly complete skeletons rested inside oval depressions. This finding, as well as other lines of evidence, have led Dr Makhubela and his colleagues to conclude now that the remains had been buried. Homo naledi lived much earlier than humans, and their fossils are at least 240,000 years old and may be as much as 500,000 years old. They also found bits of charcoal, burned bones of turtles and rabbits, and soot on the cave walls near the fossils.
This suggests that Homo naledi used glowing coals to light their way into the caves and brought wood or other fuel to burn fires. Dr Berger decided to look for himself at one of the chambers, known as Dinaledi, that contained a purported grave. He had to lose 55 pounds before he could fit through the passageway. As he made his way out, he noticed a set of hashtag-like grooves etched into the hard surface. Two members of the team, Agustin Fuentes of Princeton University and John Hawks of the University of Wisconsin, were waiting for him in the adjoining chamber.
Dr Berger showed them photos of the grooves he had taken, and they immediately pulled up the same image from a cave in Gibraltar made by Neanderthals. Based on the growing number of fossils scientists are finding in Rising Star, it looks as if Homo naledi may have visited the cave for hundreds of generations, moving together into the dark depths to bury their dead and mark the place with art. However, Mara Martinón-Torres, the director of Spain’s National Research Center on Human Evolution, said that such speculations are premature based on the evidence presented so far. Michael Petraglia, the director of the Australian Research Center for Human Evolution, is optimistic that the ovals are burials, but the jury is still out. Paul Pettitt, an archaeologist at Durham University in England, said it was possible that Homo naledi did not bring the bodies in, either for caching or burying. Joo Zilho, an archaeologist at the University of Barcelona, said the whole thing is unconvincing.
To test these possibilities, samples from the engravings, charcoal and soot must be collected to estimate their age. Dr Hawks said these experiments could take years due to the number of models to test. The team decided to present their data now and start a conversation with other scientists about how to proceed. If the researchers are correct, the findings will challenge some of the most critical assumptions about human evolution. Humans and Neanderthals have giant brains compared to earlier hominins, and paleoanthropologists have long assumed that the bigger size brought significant benefits.
However, there would have to be some upside to outweigh the problems, evolutionarily speaking, of having big brains. One benefit of a giant brain might be complex thinking, as Neanderthals have left behind an impressive record of cooperative hunting, tool use and other skills. Modern humans make symbols, use language and perform other feats of brainpower. If a hominin like Homo naledi could make engravings and dig graves, it would mean brain size was not essential to complex thought. The interesting question moving forward is what exactly big brains are needed for.
This article is initially published by nytimes.com by Carl Zimmer
