New Isotopic Evidence from Callao and Dalan Serkot Caves, Peñablanca, Cagayan Province, Philippines

Isotopic analysis of tooth enamel has proved an effective means to understand differential patterns of human foraging from remains recovered from secure prehistoric contexts. In this study, tooth enamel samples recovered from two prehistoric caves from northern Philippines, Callao Cave and Dalan Serkot Cave, with preserved Holocene contexts were analyzed for light isotope analysis of carbon and oxygen and radiogenic isotopes of strontium and potentially lead (data forthcoming). Tooth enamel samples from three human molars from each cave context in addition to one pig tooth and one deer tooth from each site were analyzed. For the light isotope human results, tooth enamel carbon ratios for the individual molars from Callao Cave (n=3) averaged -5.2 (+/- 0.73) for carbon and -5.7 (+/- 0.59) per mil for oxygen. Human results from Dalan Serkot Cave (n=3) averaged per mil -7.9 (+/- 0.68) per mil for carbon and -5.8 (+/- 0.35) per mil for oxygen. With respect to carbon isotope ratios of the fauna assayed, the pig samples were broadly similar in value, with -13.2 per mil from Dalan Serkot Cave and -13.4 per mil from Callao Cave (n=1). In contrast, the deer from Dalan Serkot Cave was significantly 13C enriched, with a carbon value of -2.0 per mil compared to the deer from Callao Cave that yielded a value of -13.0 per mil. These data are discussed with respect to comparative data available elsewhere in The Philippines and the broader region of Southeast Asia. Preliminary assessment for the human data suggests a significant portion of their diet included C4 plants and animals that foraged on C4 grasses. These data are presented in comparative context with other sites in the region.