Three hundred thousand years ago, the genus Homo emerged from the lush forests of Africa. The Middle Paleolithic Era had begun. In this period, our ancestors evolved large brains that allowed them to control fire, develop complex social rituals, and create tools. They began migrating outside of Africa. Human culture emerged for the first time: members of the Homo genus built hearths, created art from animal horns, and buried their dead. Today, evolutionary anthropologists are on the hunt for more information about this era. When exactly did this major transition occur? Where? And what critical brain mass did our ancestors achieve to make these major advancements possible?
Ancient caverns scattered across Africa may hold the answers.
Seen Right: Paleoartist John Gurche reconstructed this image of Homo naledi based on skull fragments found in the Rising Star Cave system. Courtesy of Mark Theissen, National Geographic.
About 30 miles north of Johannesburg, South Africa lies a 47,000 hectare collection of limestone caves known to archaeologists as the Cradle of Humankind. In these caves, scientists have discovered the highest concentration of hominid fossils in the world — some of which may date back 3.5 million years. Almost a century of research in the caves has enabled paleoanthropologists to fill the evolutionary gap between the Great Apes and our ancient hominid ancestors. Former inhabitants of the Cradle range from the ape-like Australopithecus africanus and Paranthropus robustus to the more familiar Homo erectus. The caves have yielded countless discoveries — the latest of which is a unique hominid species that managed to tame the greatest beast of them all: fire.
The Ancient Greeks believed that fire was a gift given to humans by the Titan Prometheus, who had stolen it from the lightning bolt of Olympian King Zeus. For this crime, Prometheus received the punishment of captivity in the Mountains of Scythia, where a falcon flew each day to tear out and eat his immortal liver. Clearly, the Greeks saw fire as a powerful thing. It took mankind from blind, wandering animals to wise, rational beings. Fire was a gift from the Gods and elevated mankind to a small kind of Godhood. Indeed, the controlled use of fire enabled our ancient ancestors to make significant advancements: with it, they could protect themselves, see at night, and cook nutritious food. Lifespans and body masses increased as a result, and so did their time to socialize and develop culture. Later on, our ancestors would even use fire to create pottery and forge metal tools.
It’s not surprising that archaeologists have been on the hunt for the first signs of controlled fire since hominid fossils were first discovered. What is surprising is where they found it. In 2013, a team of archaeologists exploring the Rising Star Cave System in the Cradle discovered hominid fossils at the bottom of a hard-to-reach chamber. The archaeologists assembled a team of researchers, dubbed the Underground Astronauts, who made the difficult journey into the cavern, where they identified 1,500 bone and tooth fragments from at least 15 individuals dating to between 236,000 and 335,000 years ago. The fossils were determined to belong to a totally new species, which they named Homo naledi. Borrowing from Sotho, a Bantu language native to the region, the name translates to “people of the stars” in honor of the cave that was once their home.
Homo naledi was a small-brained hominid living in an age dominated by big brained neighbors. Based on their tiny cranial volume, scientists expected the H. naledi bones to date back over a million years, yet this species was able to survive and compete against bigger-brained hominid species roaming Africa well into the Middle Paleolithic Era.
Seen Left: Homo naledi bone and tooth fragments found in the Rising Star Cave, ranging from old, adult, young, and infantile individuals. Adult fragments are arranged into a composite skeleton view. Courtesy of Lee Berger et al., E. Life Sciences.
The species’ brain size wasn’t the only interesting thing about them: when the Underground Astronauts dropped into the cavern that H. naledi inhabited some 300,000 years ago, they found it covered in soot. Charcoal and ash littered the limestone rock. Dozens of hearths made of stones and burnt antelope horns covered the cave floor. It appeared that these small-brained cousins of ours had mastered fire at around the same time as ancient human and Neanderthal populations. This shocked scientists and challenged the notion that a large cranial volume was a rate-limiting step in hominid evolution.
Homo naledi surprised scientists in yet another way: their dwelling showed evidence of funerary practices. According to leading H. naledi paleoanthropologist Lee Berger, the remains found in the Rising Star Cave appeared to have been deliberately carried there and arranged in an ordered fashion. The bodies were deposited at several different times, suggesting that this chasm was more than a dumping ground: it was an ancient graveyard. To evolutionary anthropologists, this signifies a complex understanding of life and death and is a sign of the emergence of culture.
Berger and his colleagues are sure to deliver even more data about this fascinating new species in coming publications. So far, these groundbreaking findings from the Cradle of Humankind have shaken the field of paleoanthropology. H. naledi challenges presumptions that a large brain size was necessary for the control of fire and the development of complex social rituals. From the fire pits Homo naledi built to light up the night to the dignified burials they gave their loved ones, it appears that our small-brained cousins were not so unlike us after all.
Seen Above: A stone hearth found in the Rising Star Chamber, covered in soot. This and several other hearths, charcoal, soot, and ash throughout the cave floor served as evidence that Homo naledi had control of fire. Courtesy of Lee Berger, Bradshaw Foundation.
