Rising Star Cave (Af. Du Sud): Did Homo naledi bury dead ?

PART.2

However, many anthropologists expressed doubt at these claims.

Professor Francis Thackery, an evolutionary biologist also at the University of Witwatersran, told Talk Radio 702 that his research suggests there may have been another entrance to the cave.

He believes the bones may have been placed closer to this entrance and then became sealed in by a roof collapse or perhaps even living individuals became trapped by the rock fall.

He said: 'To carry these 15 carcasses in complete darkness through a very narrow route in complete darkness raises questions. 

'I think in the past there could have been a second entrance.

'Dolermite rock that is quite soluble in geological time. 

'There could have been a second opening and there was a collapse and these 15 individuals had been trapped.'

He added he had studied the bones themselves and found black spots on them that he believes are marks of manganese dioxide left by lichen that grew on them in the past.

This, he believes, suggests the bones may have been in a part of the cave that was closer to an entrance where there was light as lichen needs sunlight to grow.

However, speaking to MailOnline, Professor Berger said that regardless of whether there was another entrance to the cave, it still would have been difficult for the remains to get in there.

He said there are no other remains of animals in the cave, which means the Homo naledi were using it almost exclusively. He added the evidence for lichen growth was also still speculative.

He said: 'Whatever the entrance was, it would have to conform to the same restrictive criteria - only allowing one species of animal in, over time, while not allowing externally derived sediments into the cave and restricting access to predators and scavengers.

'So if there were another entrance, it would have to be nearly if not equally as restrictive as the one we use now.

'I can understand the discomfort - we have spent more than a hundred years of this field seeing the unique behaviours of humans as being due to a big brai.

'Its not going to be easy to convince everyone that complexity is not driven by a single organs size alone - despite the evidence.'