Bacho Kiro Cave Yields Key Insights into the Technological and Behavioral Evolution of the Pioneers Homo sapiens in Europe

Recent excavations at Bacho Kiro Cave in north Bulgaria, carried out from 2015 to 2021, have shed new light on the technological and behavioral shifts of Homo sapiens during the Initial Upper Palaeolithic (IUP) period. The site's lithic assemblages, dated between 45,040 and 43,280 cal BP, include over two thousand artifacts attributed to early Homo sapiens.

The lithic implements, primarily originating from Layer I, are found alongside diverse faunal remains, human fossils, and other decorative items such as pierced animal teeth pendants. This study offers insights into the technological aspects of these lithic implements, including raw material origins, production techniques, on-site knapping activities, and the use-life of the tools. These findings significantly enhance our understanding of early Homo sapiens innovation and adaptation.

Key findings:

The analysis of the raw materials indicates that early Homo sapiens in Bacho Kiro Cave (Central North Bulgaria) were supplied with Lower Cretaceous flint from the Ludogorie area in Northeastern Bulgaria and Upper Cretaceous flints from the vicinity of Nikopol, situated on the southern bank of the Danube River. This highlights their extensive mobility, transport of finished products (blades) and logistic networks, spanning distances of up to 190 km.

The techno-economic and typological analysis of the lithic assemblages demonstrate the use of both unidirectional and bidirectional non-Levallois laminar technology, likely employing volumetric concept. Systematic bipolar knapping and tool segmentation reflect complex on-site tool curation and multifaceted lithic economy likely resulting from the remote sources of good quality flint.

Concerning cultural and behavioral evolution, evidence of on-site tool curation is associated with increased butchering activities and the crafting of bone tools, personal ornaments as pendants. These findings demonstrate advanced cultural practices and an adaptive response to environmental challenges, highlighting the behavioral plasticity of early Homo sapiens at the onset of the Upper Palaeolithic.

Bacho Kiro Cave is pivotal in understanding the technological and behavioral evolution of early Homo sapiens in Western Eurasia. The site's well-dated contexts and diverse assemblages provide a detailed picture of the Initial Upper Palaeolithic, highlighting significant behavioral variability and adaptation. Future research aims to further explore these dynamics through detailed spatial analysis and raw material economy.

"Bacho Kiro Cave offers an exceptional opportunity to understand the technologies and organization of livelihood of early Upper Paleolithic Homo sapiens," says Tsenka Tsanova, the lead researcher of this study and coordinator of the interdisciplinary research. "Our findings highlight the complexity and adaptability of these ancient Homo sapiens who settled between the Danube and the Balkan Mountains (Stara Planina)."

"In a clear departure from previous Neanderthal behaviors, the analysis of raw material origins at Bacho Kiro Cave reveals how the first European Homo sapiens planned their material needs well in advance of their arrival at the site," reports Vincent Delvigne, the petrology specialist responsible for studying the lithic collection from Bacho Kiro Cave. "This observation foreshadows the movements of modern humans over the next 30 millennia, as groups developed mobility systems between camps, sometimes located hundreds of kilometers apart."

"The innovations, adaptations, and behavioral changes observed in Bacho Kiro Cave among the early Homo sapiens in Europe were neither isolated, temporary, nor random. For instance, their systematic procurement of high-quality flint and flint blades from distant sources foreshadows an even greater entrepreneurial spirit and increased mobility in the evolution of this population. This led to their movement far to the east, with brief—and likely rarely long-term—settlements across Central, Eastern, and Northeastern Asia, ultimately culminating in their significant role in the colonization of the New World," concludes Nikolay Sirakov, the Field Director of the past excavation.

For further information and high-resolution images, please contact tsenka.tsanova@unibo.it

High-Resolution Images Available Upon Request:

Image 1. Part of the excavation team of the Bulgarian-German cooperation in 2021, in front of the entry of Bacho Kiro Cave. Back row from the left to the right: B. Milusheva, L. Vitanov, S. Simeonov, Sh.McPherron, N. Sirakov, I. Stanev(ⴕ), front row from the left to the right: V. Ivanova, Y. Dimitrova, E. Nacheva, Ts. Tsanova, J.-J. Hublin, E. Anastasova, Picture V. Simeonov.

Image 2 (title image). Excavations at Bacho Kiro Cave of the 2021 season are unearthing new artifacts from the Middle Palaeolithic Neanderthal occupations. The Initial Upper Palaeolithic Layer I can be seen as a dark band in the sediment profile. Excavators are wearing masks and gloves to minimize contamination of samples that are regularly taken for molecular analyses, picture © MPI-EVA/ Tsenka Tsanova.

Image 3. Selection of relevant stone and bone findings from the Initial Upper Paleolithic layers (I and J) from in Bacho Kiro Cave. 1-5 Pointed lithic implements, 6-7 Stone beat from psammite, 8 Ivory beat, 9 Bone polisher, 10 Pendentive- pierced animal tooth, 11 Homo sapiens molar tooth, Drawings: I. Krumov; Pictures: Ts. Tsanova (1, 2, 3, 4, 6), N. Martisius (7, 8, 10), Sh. McPherron (11).

Image 4. Analyzing three aspects of the stone collections from Bacho Kiro Cave at the National History Museum in Sofia in 2022: on the right, J. Marriros studies the use-wear; in the middle, V. Delvigne identifies the raw material; and on the left, Ts. Tsanova enters data on the technology, Picture by E. Endarova

Image 5. Part of the research team of the Bulgarian-German project and other participants in front of the monument to Bacho Kiro in the Platex guest house, in Dryanovo, October 2019. From left to right, back row: N. Martisius, M. Haidinjak, I. Krumov, S. Sirakova, D. Filcheva and V. Fish, E. Anastasova (above), E. Endarova; Foreground from left to right: V. Lafchiyski, N. Sirakov, N. Zahariev, R. Spasov, Ts. Tsanova, P. Horta and S. Pääbo, Picture P. Petrunov.