New insights into our origins

Research led by a global team including archaeologists from La Trobe University has shed new light on how humans evolved by adapting to changing environments.

Published today in Nature Communications, the research was carried out at the Panga ya Saidi cave in Kenya, a site dating back 78,000 years and the only known site in East Africa with such a long unbroken archaeological record of human habitation until 500 years ago.

Professor Andy Herries, Head of the Department of Archaeology and History at La Trobe University and an author on the paper, said that sophisticated miniaturised stone tools were found within the cave dating to around 67,000 years – significantly earlier than equivalent Late Stone Age tool technology found at other sites.

La Trobe Archaeology Honours student Richard Curtis used Australia’s only archaeomagnetism laboratory to conduct magnetic analysis of rock sediments found in the cave, to determine environmental conditions which might have affected this transition to early modern humans.

“What our analysis showed is that the shift from simpler to more sophisticated stone tools took place during one of the coldest phases of the last glacial cycle,” Mr Curtis said.

“The site documents the earliest evidence of this more sophisticated style of microlithic Later Stone Age technology and shows how early modern humans were able to adapt to a range of new environments at this time.”

Professor Herries added that while other populations at this time have been shown to have adapted to this cold phase in different ways, at Panga ya Saidi this style of microlithic technology endured until a few 100 years ago.

“Ultimately this style of technology was very successful and came to be used across Africa 44,000 years ago,” Professor Herries said.

“However, subsequent behavioural traits that we associate with modern humans, such as using crayons and shell beads, also found in the cave, developed over a much longer time period, suggesting there wasn’t a sudden ‘leap’ in modern human behavioural complexity as was previously thought.”

Richard Curtis said that once the climate stabilised itself around 60,000 years ago, a range of other adaptations including use of ochre crayons, shell beads and notched bone were gradually incorporated into the daily life of the cave’s inhabitants and there is evidence for increasing occupation of the site.

Lead author Dr Ceri Shipton, from the Australian National University (ANU), said both the sophisticated technologies and the cultural artefacts discovered in the cave are significant because of what they indicate about humans adapting to different environments.

“What is striking about this record is the innovations you see in technology and material culture, and the ability to exploit both forest and savannah environments. It is this kind of behavioural flexibility that allowed our species to populate the rest of the world outside of Africa.”

La Trobe’s Professor Andy Herries said the new findings show that rather than being caused by major global or continental cultural revolutions, human evolution is the story of populations adapting over time to new and changing environments.

“As a species we have survived due to our ability to adapt to almost every environment on the planet through our technological ingenuity,” Professor Herries said.

“This has, in turn, created a vast array of cultural complexity as we all compete for resources and space and in an effort to identify who we are as individuals and as a group.

“The question remaining is whether our behavioural and technological adaptability can survive the next great test, in an ever hostile world impacted by human-induced climate warming and instability.”

ENDS

The Nature Communications paper, 78,000-year-old record of Middle and Later stone age innovation in an East African tropical forest, was published on Wednesday 9 May 2018, 10:00 London time (BST) / 5:00am US Eastern time, 18:00 Japanese time / 21:00 Australian Eastern Time.

The project was led by the Max Planck Institute for the Science of Human History in Germany.

DOI: 10.1038/s41467-018-04057-3

Media Contact: Claire Bowers – c.bowers@latrobe.edu.au - 9479 2315 / 0437 279 903

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