Primitive Hominins Coped With Environmental Change Too

The UNESCO World Heritage Site Olduvai Gorge (now Oldupai Gorge) in northern Tanzania, known as the "cradle of mankind", achieved worldwide fame, in particular through Louis and Mary Leakey. As reported in Nature Communications , new interdisciplinary field research has now led to the discovery of the oldest archaeological site to date in the Oldupai Gorge and shows that early humans used diverse habitats amid ecological changes over a period of 200,000 years.

With a multitude of archaeological findings of extinct human species, the age of which extends over a period of several million years, the East African Trench is particularly suitable for researching the origins of mankind. However, despite more than a century of archaeological and paleontological research, the ecological context in which these early humans lived remained elusive. In particular, the lack of ecological studies directly related to cultural remains made it difficult to study the environmental conditions of the time.

For the new study published in Nature Communications was published, researchers from the Max Planck Institute for the History of Human History, the University of Calgary (Canada) and the University of Dar es Salaam (Tanzania) worked together to uncover the "Ewass Oldupa" excavation site. Ewass Oldupa means "on the way to the gorge" in the local Maa language and the archaeological site is on both sides of the path that leads from the edge of the gorge down to its bottom. The excavations unearthed Oldowan stone tools around two million years old - the oldest ever found in the Oldupai Gorge. Excavations in long sequences of layered sediments and dated volcanic horizons indicate the presence of hominins from about 2 to 1.8 million years ago in Ewass Oldupai.

Examination of the fossils of mammals (wild cattle and pigs, hippos, panthers, lions, hyenas and primates), reptiles and birds, along with a number of other multidisciplinary studies, revealed several changes in the habitat of the river and lake systems over these 200,000 years , including fern meadows, woodland mosaics, naturally burnt-down landscapes, palm groves on lake shores and dry steppe landscapes. The data show periodic and repeated use of some habitats, interrupted by periods when there was no human activity.

"The colonization of different and unstable environments, even after volcanic activity, is one of the earliest examples of adaptations to radical ecological transformations," explains Dr. Pastory Bushozi from Dar es Salaam University, Tanzania.

The colonization of changing and disturbed environments by hominini is unique for this early period and demonstrates complex behavioral adaptations in early human groups. Despite the changing habitats, early humans did not fundamentally change their tool sets, but rather their technology remained stable over time. Typical of their versatility are the typical Oldowan stone tools, which consist of pebble and cobblestone cores as well as sharp-edged flakes and polyhedral cobblestones and were also used when the habitats changed. This suggests that two million years ago early humans were able to continuously and regularly.

No human fossils have been discovered in Ewass Oldupa, but Homo habilis fossils have been found in 1.82 million year old deposits just 350 meters away . It is difficult to prove whether Homo habilis actually stayed in Ewass Oldupa, but Prof. Julio Mercader from the University of Calgary emphasizes "that these early humans most likely roamed the landscape over a large area and along the shores of old lakes". Mercader also notes that this does not rule out the possibility that other groups of hominini, such as the Australopithecina , also made and used stone tools in Ewass Oldupa. For example, it is known that the genus Paranthropuswas present in the Oldupai Gorge at the time.

The evidence gained in the Oldupai Gorge and East Africa suggests that early human mobility in and outside Africa was possible two million years ago because the hominini had the ability to expand into novel ecosystems. “This behavioral flexibility emerged with the beginning of the evolution of our own species, Homo , and paved the way for a later, invasive spread of Homo sapiens,” explains Prof. Michael Petraglia from the Max Planck Institute for the History of Human Beings.

Reference
Mercader J, Akuku P, Boivin N, et al. Earliest Olduvai hominins exploited unstable environments ~ 2 million years ago. Nature Communications. 2021;12(1):3. doi:10.1038/s41467-020-20176-2

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