Diet and habitat of late Miocene herbivore mammals from Nurpur, District Kangra, Himachal Pradesh, India

Abstract

We present the stable carbon (δ13C) and oxygen (δ18O) isotopic composition of 75 serial samples (tooth enamels) from five mammalian fossil groups, which include giraffids, equids, bovids, tragulids, and suids, to reconstruct their diet and habitat. These mammalian faunas were recovered from a late Miocene Middle Siwalik succession exposed in Nurpur, Himachal Pradesh, India (8.14–5.26 Ma). The average δ13C data of the studied mammals, that is, −13.30 ± 0.71 (giraffids), −11.29 ± 0.63 (equids), −12.68 ± 0.49‰ (bovids), −12.97 ± 1.11 (tragulids), and −12.01 ± 0.47 (suids) indicates a mainly C3 diet with a minor component of C4 grass (up to 17%) and a habitat dominant by forest/woodland. The average δ18O value of giraffids (−5.83 ± 0.85) is slightly enriched as compared to other herbivore mammals, such as equids (−8.85 ± 1.71), bovids (−7.86 ± 0.62‰), tragulids (−8.26 ± 1.92), and suids (−10.65 ± 0.23). It suggests that the browsing giraffids could likely intake water from enriched 18O sources, whereas the other browsing mammals consume water from depleted 18O sources in the local ecosystem. However, the δ18O values indicate the existence of a warm, humid climate and more precipitation in the Siwalik during the late Miocene.