Naledi's no-brainer: bigger isn’t always better
Turns out Homo naledi's small brain was more sophisticated than we might have thought
The discovery of 15 skeletons at the Cradle of Humankind sparked a worldwide fossil frenzy in 2015, and overnight, Homo naledi became a global “rock star” in the world of paleontology.
Now, a new research paper has shed more light on the mystery of this strange creature’s brain which was much smaller than our own but which, it turns out, was more sophisticated than we might have thought.The 1,500 bones found deep inside a cave system at the Sterkfontein site have dumbfounded scientists who spent the last few years delving into the many mysteries surrounding the species, including its unusual combination of features and its orange-sized brain‚ the difficulty of dating the species‚ and the theory that it had buried its dead.After more research, it was dated at about 250‚000 years ago – which means it could have walked the earth at the same time as us.This young age was surprising to scientists because it displayed primitive features such as curved fingers and the small brain.“If there is one other species that shared the world with ‘modern humans’ in Africa, it’s very likely there are others. We just need to find them,” said Professor Lee Berger of the University of the Witwatersrand at the time.
This is a puzzle to scientists, who long held that there was only one species in Africa at this late time period – Homo sapiens.
How did this species exist alongside others with brains three times its size?
The new study suggests that naledi’s behaviour may have reflected the shape and structure of the brain more than its size.Its skull was only slightly larger than that of a chimp but looked surprisingly like our own and had a more developed frontal lobe than previously thought.
In other words, size doesn’t count.A humanlike brain organisation might mean that naledi shared some behaviours with humans despite having this much smaller brain size.
The University of the Witwatersrand released a statement saying that researchers pieced together traces of Homo naledi’s brain shape “from an extraordinary collection of skull fragments and partial crania, from at least five adult individuals”.One of these bore a very clear imprint of the convolutions on the surface of the brain’s left frontal lobe.
“This is the skull I’ve been waiting for my whole career,” said lead author Ralph Holloway, of Columbia University.Lee Berger, a co-author on the paper, suggests that the recognition of naledi’s small but complex brain will also have a significant impact on the study of African archaeology.
“Archaeologists have been too quick to assume that complex stone tool industries were made by modern humans. With naledi being found in southern Africa, at the same time and place that the Middle Stone Age industry emerged, maybe we’ve had the story wrong the whole time.”