Homo naledi is said to have started fires in caves at least 236,000 years ago

An ancient hominid nicknamed Homo naledi may have started controlled fires in the dark chambers of an underground cave system, according to new findings.

Researchers have found remnants of small chimneys and soot stains on the walls and ceiling in passages and chambers throughout South Africa’s Rising Star cave complex, paleoanthropologist Lee Berger announced at a Dec. 1 conference hosted by the Carnegie Institution of Science in Washington, D.C.

“Signs of fire use are everywhere in this cave system,” said Berger, of the University of the Witwatersrand, Johannesburg.

H. naledi presumably started the flames in the caves since the remains of no other hominids appeared there, according to the team. But researchers have yet to date the age of the fire remains. And researchers outside of Berger’s group have yet to evaluate the new findings.

H. naledi the fossils date from between 335,000 and 236,000 years ago (SN: 5/9/17), around the period Homo sapiens native (SN: 6/7/17). Many researchers suspect that the regular use of fire by hominids for light, warmth and cooking started about 400,000 years ago (SN: 02/04/12).

Such behavior has not been attributed to H. naledi before, largely because of his small brain. But it is now clear that a brain about one-third the size of today’s human brain still allows H. naledi to control the fire, Berger argues.

Last August, Berger descended into a narrow shaft and examined two subterranean chambers where H. naledi fossils had been discovered. He noticed stalactites and thin slabs of rock that had partly grown on older ceiling surfaces. Those surfaces had blackened, burnt areas and were also dotted with what appeared to be soot particles, Berger said.

Meanwhile, Wits’ expedition co-leader and paleoanthropologist Keneiloe Molopyane led the excavation of a nearby cave chamber. There, the researchers discovered two small chimneys containing charred pieces of wood and burnt bones of antelopes and other animals. Remains of a fireplace and animal bones burned nearby were later discovered in a more distant cave where H. naledi fossils have been discovered.

Still, the main challenge for investigators will be to date the burnt wood and bones and other fire remains from the Rising Star chambers and to demonstrate that the chimneys come from the same sediment layers as H. naledi fossils, says paleoanthropologist W. Andrew Barr of George Washington University in Washington, DC, who was not involved in the work.

“This is an absolutely critical first step before it’s possible to speculate who may have started fires for what reason,” Barr said.