Pursuant to his major research interest in the cultural ecology of hunter-gatherers, Birdsell collected an unparalleled body of phenotypic data on Aboriginal Australians during the mid twentieth century. Birdsell did not explicitly relate the geographic patterning in his data to Australia's climatic variation, instead arguing that the observable differences between groups reflect multiple origins of Australian Aborigines. In this article, bivariate correlation and multivariate analyses demonstrate statistically significant associations between climatic variables and the body build of Australians that are consistent with the theoretical expectations of Bergmann's and Allen's rules. While Australian Aborigines in comparison to Eurasian and New World populations can be generally described as long-headed, linear in build, and characterized by elongated distal limbs, the variation in this morphological pattern across the continent evidently reflects biological adaptation to local Holocene climates. These results add to a growing body of evidence for the role of environmental selection in the development of modern human variation.