Ancient human cousins may have buried their dead

An ancient human cousin may have buried its dead and carved symbols into cave walls, surprising findings for a creature with a small brain.

Fossil remains of the species — named Homo naledi — were uncovered in underground caves in South Africa a decade ago. Now, researchers say they’ve found evidence the species was capable of complex behaviour that so far has only been seen in those with bigger brains.

“We are facing a remarkable discovery here” for a species with brains one-third the size of humans, said anthropologist Lee Berger, who led the research funded by the National Geographic Society, where he now works.

Berger and colleagues describe their findings in studies posted online Monday. The research has not been peer-reviewed yet and some outside scientists think more evidence is needed to challenge what we know about how humans evolved their complex thinking.

“There’s still a lot to uncover,” said Rick Potts, director of the Smithsonian’s Human Origins Program who was not involved in the research.

H. naledi is a pretty new addition to the family tree of hominins, which includes our direct ancestors and other extinct relatives who walked on two legs. Berger and his team announced the species in 2015, after a tip from local spelunkers led them to the Rising Star cave system near Johannesburg where they uncovered fossils from at least 15 individuals who lived around 300,000 years ago.

These creatures had traits in common with modern humans, like legs made for walking upright and hands that could work with objects, said University of Wisconsin-Madison anthropologist John Hawks. But other features looked more ancient, including their small brains.

In recent years, team members have ventured back into the caves, a tricky descent through tight underground spaces. What’s down there shows the species in a new light, they reported.

One of the studies describes what researchers say were intentional burial sites. The team uncovered fossil remains of adults and children in shallow holes in the ground, their bodies in a fetal position.

All of this behaviour would be surprising for a creature whose brain was closer in size to an ape’s than a human’s, experts said.

Researchers say the species, whose brains were one-third the size of humans, was capable of complex behaviour that has only been seen in those with bigger brains