May 9 (UPI) -- Archaeologists have recovered evidence of early cultural innovations dating to 67,000 years ago from a cave near the coast of East Africa.
Until now, little was known about human history in East Africa over the last 78,000 years, with most archaeological research focused on the Rift Valley and in South Africa.
In addition to evidence of human occupation, researchers recovered plant and animal remains, helping them to recreate a timeline of the area's ecological history. Their findings suggest the area's climate and ecosystem -- a forest-grassland ecotone, a transition between forest and grassland ecosystems -- has remained stable over the last 78,000 years.
The ecological record confirms humans' ability to adapt to a range of habitats.
"The East African coastal hinterland and its forests and have been long considered to be marginal to human evolution so the discovery of Panga ya Saidi cave will certainly change archaeologists' views and perceptions," Nicole Boivin, archaeologist at the Max Planck Institute for the Science of Human History, said in a news release.
Researchers recovered stone toolkits dating back to 78,000 years ago. The stone artifacts revealed a technological shift around the Later Stone Age, around 67,000 years ago. Archaeologists believe the adoptions of miniaturized stones may reflect a shift in hunting strategies.
The artifacts -- detailed this week in the journal Nature Communications -- suggest the cave was continuously occupied by early humans, offering additional proof that human populations in the region were able to survive the climatic effects of the Toba volcanic super-eruption 74,000 years ago.
In addition to stone toolkits, researchers recovered incised bones, ostrich eggshell beads, marine shell beads and artifacts adorned with ochre -- evidence of cultural innovations. Some of the beads were dated 65,000 years old, making them the oldest found in Kenya.
Though the beads prove the cave's occupants regularly visited the coast, there are no signs the population harvested marine resources for subsistence.
Together, the artifacts found at Panga ya Saidi suggest human populations living in the region were healthy, stable and growing -- in both size and cultural complexity -- over thousands of years.
"The finds at Panga ya Saidi undermine hypotheses about the use of coasts as a kind of 'superhighway' that channeled migrating humans out of Africa, and around the Indian Ocean rim," said pofessor Michael Petraglia.