Hunter-Gatherers, Biogeographic Barriers and the Development of Human Settlement in Tierra del Fuego

Article excerpt

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Introduction

The archaeology of sea barriers comprises a variety of situations, many of which concern the colonisation of oceanic islands (Cherry 1981) or particularly difficult crossings like the Strait of Gibraltar (Derricourt 2005). In contrast, Tierra del Fuego (520-550S), located in southernmost South America, was intermittently joined to the Patagonian mainland until c. 8000 BP, when it became an island. The significance of Tierra del Fuego for global archaeology lies both in being the southern limit of human dispersal in the Americas, and in having been home to culturally distinct terrestrial and maritime hunter-gatherer groups that persisted until the twentieth century AD. In this paper we summarise extant knowledge about the earliest human occupation of the island and discuss existing and new evidence for long-distance interaction during its subsequent human occupation.

Island Tierra del Fuego

After the Last Glacial Maximum (c. 25 000-23 000 BP) glaciers re-advanced on two occasions, generating windows of opportunity for early people to migrate from Patagonia to Tierra del Fuego (McCulloch & Morello 2009). After c. 10 315 BP, Early Holocene warming led to the rapid retreat of the Patagonian ice fields but global sea levels continued to be approximately 20-60m below present-day sea levels, forming a land bridge across what today is an inter-oceanic passage, the Strait of Magellan. This situation persisted until the start of marine incursion, at c. 8300-7500 BP (McCulloch et al. 2005).

The main island of Tierra del Fuego, Isla Grande de Tierra del Fuego, today is over 250km long and 400km wide (Figure 1). The north-central zone is dominated by plains and rolling hills and the southern part is shaped by the Darwin Cordillera, an extension of the Andean range. A mean annual temperature of 5[degrees]C and rainfall of around 400mm per year reflect the influence of the Westerlies (Pisano 1977). Among the noteworthy Holocene fauna are guanaco (Lama guanicoe), fox (Dusicyon culpaeus) and rodents, in particular coruro (Ctenomys sp). The low density of terrestrial mammals is supplemented by permanent and seasonal marine and terrestrial birds, e.g. caiquen (Chloephagapicta), albatros (Diomedea melanophris) and penguin (Aptenodytes patagonicus, Spheniscus magellanicus), as well as by marine mammals such as sea lions (Otaria flavescens and Arctocephalus australis) and cetaceans, along with fish and mollusks. Broadly speaking, the northern half of the island is dominated by open vegetation while the southern half is characterised by southern beech forest.

The view from ethnography

Nomadic hunter-gatherers were observed inhabiting the region from the first European sighting of the Strait of Magellan in 1520. Ethnographic accounts record two distinct groups in Tierra del Fuego and mainland Patagonia: maritime hunter-gatherers (Alacalufe/ Kaweskar and Yamana/Yagan) were skilled navigators who relied on bark canoes but rarely ventured far inland (their archaeological record of shell middens first appears in the region around 6500 BP (Legoupil & Fontugne 1997). Terrestrial hunter-gatherers (Tehuelches/Aonikenk and Selk'nam/Ona in Tierra del Fuego) were averse to using vessels for water travel. Only the Aonikenk were recorded using makeshift rafts (made with tent sticks, branches and/or skins) to cross the Santa Cruz and Chico rivers (Fitzroy 1837:119; Moreno 1969 [1879]: 242; Burucua 1974: 54; Lista 1975: 42). Selk'nam escaping from the Salesian Mission on Dawson Island had to be helped by maritime hunter-gatherers to reach the main island of Tierra del Fuego by canoe (Chapman 2007).

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Early environment and arrival of humans

Palaeoecological evidence suggests that the late glacial environment was predominantly open steppe and that the climate was significantly colder and drier than present. …