Flexibility of diet and habitat in Pleistocene South Asian mammals: Implications for the fate of the giant fossil ape Gigantopithecus Herv  e Bocherens a, b, * , Friedemann Schrenk c , Yaowalak Chaimanee d , Ottmar Kullmer c , Doris M € orike e , Diana Pushkina d , Jean-Jacques Jaeger d a Universit€ at Tübingen, Fachbereich Geowissenschaften, Biogeologie, H€ olderlinstrasse 12, D-72074 Tübingen, Germany b Senckenberg Center for Human Evolution and Palaeoenvironment (HEP), Universit€ at Tübingen, H€ olderlinstrasse 12, D-72074 Tübingen, Germany c Senckenberg Research Institute Frankfurt a. M., Department of Palaeoanthropology and Messel Research, Senckenberganlage 25, 60325 Frankfurt am Main, Germany d IPHEP: Institut de Pal eoprimatologie, Pal eontologie Humaine: Evolution et Pal eoenvironnements, CNRS UMR 7262, Universit e de Poitiers, 6 rue Michel Brunet, 86073 Poitiers Cedex 9, France e Staatliches Museum für Naturkunde Stuttgart, Sektion Mammalogie und Osteologie, D-70191 Stuttgart, Germany article info Article history: Available online 19 December 2015 Keywords: Enamel stable isotopes Extinction Gigantopithecus Palaeodiet Pongo abstract Determining the diet of fossil apes is essential to understand primate evolution. The giant form from Southeast Asia, Gigantopithecus blacki, may have been up to 270 kg and survived until about 100,000 years ago. It is known only from isolated teeth and a few lower jaws with reduced front teeth and enlarged molars and premolars. A large spectrum of diets has been suggested for Gigantopithecus, ranging from carnivorous or grass-feeding in open savannah to a vegetarian diet dominated by fruits or bamboo. To determine its habitat and to understand why it became extinct, we tried to evaluate its dietary niche. The carbon stable isotopic composition of tooth enamel of this taxon compared to coeval and extant mammals from Southeastern Asia show that Gigantopithecus was a forest-dweller with a generalist vegetarian diet and was not specialized on bamboos. In southern China, Gigantopithecus lived in a forested environment, as did the coeval fauna, while in Thailand, it occupied only the forested part of a mosaic landscape including significant parts of open savannah. The carbon isotopic compositions of Gigantopithecus were different from those of omnivorous and carnivorous taxa, but very similar to those of orang-utans and unlike those of the bamboo-specialist giant panda. Therefore, even when open savannah environments were present in the landscape, Gigantopithecus foraging was limited to forested habitats. The very large size of Gigantopithecus, combined with a relatively restricted dietary niche, may explain its demise during the drastic forest reduction that characterized the glacial periods in South East Asia. © 2015 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction South East Asia is still populated by a diverse assemblage of mega-mammal species, although most of them are now endan- gered, and several species became extinct recently in this region (e.g. Chaimanee, 2007; Louys et al., 2007; Stuart, 2015). The possible causes of these extinctions are debated, including climate change, human impact and eustatic changes in sea levels (e.g. Louys et al., 2007). One crucial information that is needed to elucidate the possible impact of these factors is the range of ecological flexibility of extinct species compared to those that survived, as it is predicted that climate change will have a stronger impact on species with limited ecological flexibility, whereas species with more flexibility would be more likely to retreat into other types of habitats (e.g. Bennett et al., 2005; Alberts and Altmann, 2006; Lorenzen et al., 2011; Bocherens et al., 2014). Among the large mammal species that suffered from dramatic reduction of their distribution area to the point of becoming en- dangered or even extinct are hominoid primates such as orang- utan Pongo and the giant ape Gigantopithecus (e.g. Tougard et al., 1996; Louys et al., 2007). Gigantopithecus is probably the largest ape that ever existed on Earth, with an estimated body mass of up to 270 kg (Simons and Ettel, 1970). This taxon was restricted to the Plio-Pleistocene of southern China and the northern part of South- East Asia and is a component of the so-called Stegodon-Ailuropoda * Corresponding author. Universit€ at Tübingen, Fachbereich Geowissenschaften, Biogeologie, H€ olderlinstrasse 12, D-72074 Tübingen, Germany. E-mail address: herve.bocherens@uni-tuebingen.de (H. Bocherens). Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint http://dx.doi.org/10.1016/j.quaint.2015.11.059 1040-6182/© 2015 Elsevier Ltd and INQUA. All rights reserved. Quaternary International 434 (2017) 148e155