Birch tar production does not prove Neanderthal behavioral complexity

Birch tar production by Neanderthals—used for hafting tools—has been interpreted as one of the earliest manifestations of modern cultural behavior. This is because birch tar production per se was assumed to require a cognitively demanding setup, in which birch bark is heated in anaerobic conditions,...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2019-09, Vol.116 (36), p.17707-17711
Main Authors: Schmidt, Patrick, Blessing, Matthias, Rageot, Maxime, Iovita, Radu, Pfleging, Johannes, Nickel, Klaus G., Righetti, Ludovic, Tennie, Claudio
Format: Article
Language:English
Subjects:
Aerobic conditions
Anaerobic conditions
Animals
Archaeology
Bark
Behavior, Animal - physiology
Betula
Burning
Chemical analysis
Cognition
Cognition - physiology
Complexity
Hominids
Lifesaving
Mechanical tests
Neanderthals - physiology
Organic chemistry
Procurement
Social Sciences
Tar
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Summary:Birch tar production by Neanderthals—used for hafting tools—has been interpreted as one of the earliest manifestations of modern cultural behavior. This is because birch tar production per se was assumed to require a cognitively demanding setup, in which birch bark is heated in anaerobic conditions, a setup whose inherent complexity was thought to require modern levels of cognition and cultural transmission. Here we demonstrate that recognizable amounts of birch tar were likely a relatively frequent byproduct of burning birch bark (a natural tinder) under common, i.e., aerobic, conditions. We show that when birch bark burns close to a vertical to subvertical hard surface, such as an adjacent stone, birch tar is naturally deposited and can be easily scraped off the surface. The burning of birch bark near suitable surfaces provides useable quantities of birch tar in a single work session (3 h; including birch bark procurement). Chemical analysis of the resulting tar showed typical markers present in archaeological tar. Mechanical tests verify the tar’s suitability for hafting and for hafted tools use. Given that similarly sized stones as in our experiment are frequently found in archaeological contexts associated with Neanderthals, the cognitively undemanding connection between burning birch bark and the production of birch tar would have been readily discoverable multiple times. Thus, the presence of birch tar alone cannot indicate the presence of modern cognition and/or cultural behaviors in Neanderthals.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1911137116