An international team of archaeologists and paleoanthropologists has discovered a large collection of 2-million-year-old stone tools, fossilized bones and plant materials at the site of Ewass Oldupa in the western portion of the ancient basin of Olduvai Gorge (now Oldupai) in northern Tanzania. The discovery reveals that the earliest Olduvai hominins used diverse, rapidly changing environments that ranged from fern meadows to woodland mosaics, naturally burned landscapes, to lakeside woodland/palm groves as well as steppes.
The newly-discovered stone tools belong to the Oldowan, the oldest-known stone tool industry.
Dating as far back as 2.6 million years ago, the Oldowan tools were likely manufactured by Homo habilis, and are a major milestone in human evolutionary history.
“Our research sheds further light on our distant origins and evolutionary history,” said co-author Professor Tristan Carter, a researcher in the Department of Anthropology at McMaster University.
“The exposed canyon wall reveals 2 million years of geological history and ancient sediments have preserved the stone artifacts remarkably, as well as human and faunal remains.”
The concentration of stone tools and animal fossils (wild cattle, pigs, hippos, panthers, lions, hyena, primates, reptiles, and birds) at the Ewass Oldupa site are evidence that both human and animal life centered around water sources.
“Our research reveals that the geological, sedimentary and plant landscapes around Ewass Oldupa changed a lot, and quickly,” the researchers said.
“Yet humans kept coming back here to use local resources for over 200,000 years.”
“They used a great diversity of habitats: fern meadows, woodland mosaics, naturally burned landscapes, lakeside palm groves, steppes.”
“These habitats were regularly blanketed by ash or reworked by mass flows associated with volcanic eruptions.”
“The occupation of varied and unstable environments, including after volcanic activity, is one of the earliest examples of adaptation to major ecological transformations,” said co-author Dr. Pastory Bushozi, a researcher at Dar es Salaam University.
The scientists also compared the chemical composition of the Ewass Oldupa tools and determined the majority of rocks used to make them had been obtained 12 km (7.5 miles) away from the site.
“This indicates planned behavior at an early stage in human evolution,” said co-author Julien Favreau, a Ph.D. candidate in the Department of Anthropology at McMaster University.
“The artifacts are truly spectacular in terms of their age, but what they really show is that through time, human ancestors were occupying vastly different environments with only one tool kit. It really speaks to their behavioral flexibility and ecological adaptability.”
“Geological, sedimentary and plant landscapes were changing dramatically and quickly at the time,” said lead author Dr. Julio Mercader, a researcher in the Department of Anthropology and Archaeology at the University of Calgary.
Thanks to past and ongoing radiometric work, the team was able to date the artifacts to a period known as the Early Pleistocene, 2 million years ago.
What’s not clear is which hominin species made the tools.
“We did not recover hominin fossils, but the remains of Homo habilis have been found in the younger sediments from another site just 350 m (1,148 feet) away,” the authors said.
“It’s likely that either Homo habilis or a member of the genus Paranthropus — remains of which have also been found at Olduvai Gorge previously — was the tool maker. More research will be needed to be sure.”
The findings were published in the journal Nature Communications.
J. Mercader et al. 2021. Earliest Olduvai hominins exploited unstable environments ~ 2 million years ago. Nat Commun 12, 3; doi: 10.1038/s41467-020-20176-2
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