Ecophysiology of Australian arid-zone reptiles

Abstract

Australia’s reptilian fauna is much richer in number of species than that of other desert regions of the world but their ecophysiology has been little studied, and we only have speculations and hypotheses to account for their abundance and diversity. There appears to be no study to date of temperature regulation or osmoregulation of a desert snake, and only a single one of an arid-zone gecko, and most published work has focused on agamid and varanid lizards. A number of agamids have been found to be semelparous, dying after breeding in spring, and thereby avoiding the need for specific adaptations to survive the long, hot and dry summer period. Such specific adaptations have yet to be identified and the inherently low rates of water turnover and resource utilisation of Australian reptiles, coupled with ectothermy and wide thermal safety zones, appear to be the primary reason for their success in arid environments, although they may face future challenges from global warming.