Colonising Sahul

Abstract

A vague notion of 'wanderlust' seems to be the driving force in many narratives about hominin migration (e.g. Dennell and Roebroeks 2005), but, true to the zeitgeist, O'Connell and Allen have shown us that wanderlust is all about food. The strength of behavioural ecology is the explicit nature of the underlying assumptions and the clear connection between forager theory, predictive statements and archaeological evidence. Summarising several optimal foraging models, O'Connell and Allen conclude that optimising hominins are pulled from patch to patch by the serial depletion of highest ranked resources. The logic of their scenario is straightforward: the archaeological record shows that humans colonised Wallacea and Sahul, and the theoretical model stipulates that forager movement is linked to exploitation of highest ranked prey, therefore colonisation was driven by the pursuit of highest ranked prey. One might question whether certain assumptions of optimal foraging models - for example, that foragers have perfect resource knowledge and the perfect ability to exploit it - would apply to the first wave of colonists to cross the Wallace Line, but the successful colonisation itself might be de facto evidence that the costs of imperfect knowledge were not prohibitively high. O'Connell and Allen posit that, after colonisation, movement between patches in pursuit of highest ranked prey became the norm as foragers made nearly-continuous readjustment to unstable climatic conditions.