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

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 event. This is evident from fireplaces, abundant lithic tools, and a wide human diet, proved by the presence of marine and terrestrial specimens and several plant macroremains (charcoal, seeds, and fruits). This event continues to spark debates about the causes of changes in human behavior and subsistence strategies. Therefore, the El Mazo long sequence allows for identifying human subsistence patterns before, during, and after the 8.2 ka event. Regarding the use of terrestrial mammals, archeozoological and taphonomic analysis indicates the red deer as the primary prey, followed by wild boar and roe deer, with a high representation of adults and juveniles. Cut and percussion marks are associated with disarticulation and skinning on those prey. At the same time, thermoalteration is abundant along the sequence and was the most common alteration observed in the macromammal assemblage. The high representation of fragmented axial bones, including ribs and vertebrae, and fetal/newborn elements prevented more detailed information about human subsistence and prey transport, which drove those bones to be identifiable primarily to mammal size. As a result, these bones are often classified as indeterminate or identified only as size class. To tackle this morphological limitation, in this study, we applied ZooArchaeology by Mass Spectrometry (ZooMS) to determine the whole spectrum of axial elements. Proteomics results indicate those remains correspond mainly to adult and infant red deer and wild boar. Besides, it shows a broader herbivore and carnivore spectrum than archaeozoology showed, including humans, bovines, small carnivores, canids, 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 event significantly impacted human subsistence and population decline. After the 8.2 ka event, intensification indices show that herbivore consumption increased significantly, overexploiting all available resources, while marine resources intensified.