Insights into early Holocene hunter-gatherer mobility on the Peruvian Southern Coast from mollusk gathering seasonality

Quebrada de los Burros (QLB) is an early Archaic coastal archaeological site in southern Peru (∼18.1°S) and the most extensively studied in the area for this period. It was occupied from 10 to 6.5 ka by fishermen also practicing hunting and mollusk gathering. Shell growth lines in 116 individuals of the surf clam Mesodesma donacium were studied to determine the month of their death (±2 months). Our results show that, for the whole occupation period, mollusk gathering was a seasonal activity mainly practiced during austral spring and summer. A change occurred between the early and the middle Holocene: the mollusk gathering season in the middle Holocene occurred ∼3 months earlier in the year than in the older levels. This behavior change could have a cultural origin, rather than dictated by the environment for it is associated with changes in the lithic industry. QLB occupants also hunted herbivores in the nearby lomas ecosystems. These plant communities only grow during the fog season from June to December, suggesting that the site was occupied during this season. A comparison of the span of the mollusk gathering season and the lomas season suggests that, at least during the early Holocene, QLB was occupied all the year round. A permanent freshwater source and the proximity of the sea, the lomas, and raw lithic materials, provided ideal conditions for a permanent occupation. This result reveals a strategy based on a seasonal alternation between marine and terrestrial resources exploitation.