Human subsistence before and after the 8.2 ka cal BP event in Northern Iberia: archaeozoology and proteomic data from the macromammal assemblage of El Mazo Rock Shelter

Abstract

El Mazo rock shelter (Asturias, Spain) contains a long and well-dated Mesolithic sequence that shows an extended human presence between 9 and 7.4 ka cal BP, including the climatic 8.2 ka cal BP event, characterized by abrupt temperature drops and drastic environmental changes. Human activities were evidenced by abundant lithic tools, fireplaces, marine and terrestrial specimens, and plant macroremains. This climatic event continues to trigger debates about the causes of changes in human behavior and subsistence strategies. Therefore, the El Mazo long sequence allows for identifying and comparing human subsistence patterns before, during, and after the 8.2 ka cal BP event. The archaeozoological and taphonomic analysis of the macromammal assemblage indicates red deer as the primary prey, followed by wild boar and roe deer, with a high representation of adults but also juveniles. Cut and percussion marks are associated with disarticulation and skinning activities on the carcasses. At the same time, burnt bones were abundant in the sequence. Despite the significant representation of axial bones, including ribs and vertebrae, and fetal/newborn elements, their high fragmentation drove those bones to be identifiable primarily to mammal size, which prevented more detailed information about hunting strategies, prey transport, and site seasonality. To tackle this morphological limitation, we applied Zooarchaeology by Mass Spectrometry (ZooMS) in this study to determine the whole spectrum of axial and newborn elements. Proteomics results indicate that adult and infant remains correspond mainly to red deer and wild boar. Besides, it shows a broader herbivore and carnivore spectrum than archaeozoology showed, including humans, bovines, small carnivores, or undetected species such as the Eurasian beaver. Finally, the mammal assemblage reveals how the sudden temperature decrease during the 8.2 ka cal BP significantly impacted terrestrial animal exploitation. After the 8.2 ka cal BP event, intensification indices show that the consumption of herbivores and marine resources increased significantly.