A Neanderthal's specialised burning structure compatible with tar obtention

Here we present multiproxy evidence of a new type of Neanderthal hearth discovered in Vanguard Cave (VC) (Gibraltar), which is dated ∼ 65 kyr, and associated with Middle Paleolithic stone artefacts. The hearth structure coincides with predictions from theoretical studies which require the use of heating structures for obtaining birch tar, commonly used in hafting. We propose that the structure was used for heating rockroses (Cistaceae) under anoxic conditions by burning herbs and shrubs, over a guano mixed with sand layer. We tested this hypothesis experimentally with success. The presence of levoglucosan and retene in the structure's matrix points to combustion of higher resinous plant-derived material. Our results advance our understanding of Neanderthal behaviour, as the ability to organize activities related with the use of fire.