Scars for survival: high cost male initiation rites are strongly associated with desert habitat in Pama-Nyungan Australia

Costly ritual behaviours have frequently been of interest to evolutionary researchers seeking to understand whether they have an adaptive benefit. Here we examine the costliness of initiation rituals across a large group of hunter-gather societies in Pama-Nyungan Australia and compare these with a range of possible adaptive benefits, including warfare, food sharing, demography, and mate competition. We find that in Australia, desert habitat was mostly strongly associated with these rites. Such rites may support the collective action, such as food sharing, necessary for survival in such a precarious environment.