Size and weight estimations of subfossil monitor lizards (Varanus sp. Merrem 1820) with an application to the Hoabinhian assemblage of Doi Pha Kan (Late Pleistocene, Lampang province, Thailand)

Abstract

Several Late Pleistocene and Holocene South-East Asian subfossil deposits are known to contain important osteological assemblages of Monitor lizards (Varanus sp.) possibly accumulated by past human populations. Indeed, thanks to their large sizes, Monitor lizards are supposed to have been an important source of meat intake for past hunter-gatherer groups. However, the taphonomic and zooarchaeological study of their bones currently suffers from strong limitations related to the lack of appropriate comparative frameworks concerning their osteology and osteometry. These limitations preclude having a good understanding of the biological characteristics of subfossil individuals but also of their accumulation process in the sites and their possible exploitation by past humans. In the present study, we try to solve these issues by producing size and weight estimation equations using bone measurements that are applicable to subfossil Southeast Asian Varanus. These equations are then applied to the study of an archaeological assemblage of Varanus from a Late Pleistocene Thai deposit, the Doi Pha Kan rock shelter. The obtained data help to demonstrate that these lizards were accumulated by Hoabinhian hunter-gatherers, and allow for the description of the hunting strategies of these human groups. We also demonstrate the interest to develop new methodological tools concerning taxa of tropical areas that present a rich biodiversity but remain understudied in zooarchaeology.