Decadal-Scale Climate Cycles Preserved in Elephas maximus Dental Tissues from Bangka Island

Julien Louys1*, Justyna J. Miszkiewicz2,3, Penny Higgins4, Mathieu Duval5, Yahdi Zaim6, Mika R. Puspaningrum7, Yan Rizal7, Aswan7, Joshua M. Rowe1, Pauline Basilia8, Loïc Martin9, Sebastian Breitenbach10, and Gilbert Price2

Faunal remains provide a proximal and plentiful source of palaeoenvironmental information in Southeast Asia, with megaherbivores an important but underused resource of sub-annual to centennial environmental dynamics. Here, we present directly dated, serially sampled enamel stable carbon and oxygen isotope ratios from specimens of the Asian elephant from the island of Bangka, southeast of Sumatra. These remains are assigned to the early Holocene based on combined U-series and ESR analysis. Carbon and oxygen isotope records demonstrate the animal lived in wet, C3-dominated ecosystems. An analysis of periodicity in the stable isotope time series are consistent with the impact of 11-year sunspot cycles, the first time this has been reported in animal tissues. While the preservation and interpretation of climatic data from animal tissues is unlikely to be straightforward or unambiguous, we provide plausible models explaining how δ18O and δ13C in elephant teeth enamel may be influenced by insolation changes via the Sun’s impact on monsoon intensity and associated hydrological and vegetation changes, respectively. This finding suggests a potential new source of high resolution palaeoclimate data where other traditional records are not available. The presented specimens indicate that a modern monsoonal system, whereby a negative Indian Ocean Dipole coupled with the La Niña phase of the El Niño-Southern Oscillation produces higher regional precipitation, was in place by the early Holocene in Island Southeast Asia.