Resisting the Cold in Ice Age Tasmania: Thermal Environment and Settlement Strategies
Gilligan, Ian, Antiquity
Humans had reached Tasmania by 35 000 years bp and were in residence at the peak of the last ice age. Curiously, the settlements in the coldest period are concentrated in the highest and most southerly places, and the colder the weather became, the more sites were occupied. The author deduces that early people specially sought out the rock shelters of the highlands to combat wind chill.
Keywords: cave sites, cold adaptation, shelter, Tasmanian Aborigines
The presence of humans in the Tasmanian region during the Last Glacial Maximum (LGM) is attested by cave and rockshelter sites dating from 35 000 years ago (35ka). These are concentrated in the remote south-west highlands (Cosgrove 1999) together with sites on a few Bass Strait islands (Bowdler 1984; Sim 1991; Brown 1993). In contrast, the ethnographic and archaeological records suggest that this south-western region had only ephemeral use in the Holocene. This raises the question of how humans survived there during the ice age and, particularly, why sites should occur at higher inland elevations. The present study draws attention to local thermal environments and predictable human responses to them when conditions approach or exceed certain limits. An awareness of thermal physiology has yet to permeate an archaeological tradition that emphasises the impact of climatic change on comestible resources. It may appear that thermal factors are too 'simple' an explanation and that judgments about temperature tolerances should be made with caution, if at all' (Bowdler 1984: 130). The existence of sites in close proximity to ice sheets certainly 'challenges the idea that these areas were too cold for hunter/gatherers' (Pike-Tay & Cosgrove 2002: 138), as does evidence that sites were visited during winter (Cosgrove & Pike-Tay 2004: 329). The availability of natural shelter in the south-west has been cited as an advantage (e.g. Freslov 1993: 237), but patterns of site utilisation are said to suggest 'no necessary correlation between the intensity of glacial conditions and cave use' (Cosgrove et al. 1990: 66). Research has instead focused on food resource options, with small marsupials representing a high-value resource that could be reliably exploited in the south-west (Cosgrove 1999).
But alternatively, and perhaps counter-intuitively, the presence of sites at more elevated and southerly inland locations could reflect thermal needs, with access to shelter, not food, being the crucial issue. To explore this possibility, the physiology of cold tolerance is reviewed in the light of ethnography and findings from experimental research. This is followed by a palaeoenvironmental reconstruction of thermal conditions in Tasmania during the late Pleistocene and an analysis of relevant archaeological data with respect to thermal indices.
Resisting the cold: ethnographic and experimental data
Ethnographic accounts of Tasmanian Aborigines in the late Holocene document a different picture to that of the late Pleistocene. Most of the 50 or so bands were based in coastal areas (Figure 1), and seasonal movements favoured the coastal zones in winter months (Jones 1974). None remained inland all year, nor did they frequent the rugged ranges of the south-west (Plomley 1966: 128). The typical absence of clothing at the time of European contact demonstrates a remarkable degree of cold tolerance. But these peoples practised all three fundamental human behavioural responses to cold--fire, shelter and, at times, clothing in the form of short wallaby-skin cloaks. Artificial shelters included wind-breaks and temporary huts (e.g. La Billardiere 1800: 99-102; d'Entrecasteaux 2001 : 31). The use of huts was seasonal, with those on the exposed western coast of more substantial construction (Jorgensen 1829: 48-9).
Experimental findings relating to human responses to varying thermal conditions are well-documented (e.g. Jessen 2001; Parsons 2003: 293-325). …