Influential Theories on Aboriginal Migration
Since the 1950s several influential theories have been proposed to explain how Aboriginal people spread throughout Australia and how quickly (Flood 2004: 79-82).
Birdsell (1957) first speculated that people moved rapidly in all directions from their arrival point, but then populated the inland regions more quickly than the coasts. His reasoning was that because the drier inland regions could support fewer people than the well-watered coastal zones, the land’s carrying capacity would be reached sooner, and people would be forced to move on in search of a new foraging areas more frequently. His theory assumes that those people entering the continent had an adaptable economy that quickly utilised and adapted to the new continent’s resources and different environmental zones.
The theory also involves numerous assumptions about generation length, rate of reproduction and group size, all based on an estimated Australian Aboriginal population at time of European arrival of approximately 300,000. Using this information, he estimates it would have taken an initial colonising population of 25 individuals 2204 years to occupy and populate Australia and Tasmania.
Birdsell’s theory has been notably challenged on archaeological and environmental grounds. Analysing the known data from Australian archaeological research, Bowdler (1977: 105-246) proposed an alternative hypothesis in 1977 of a coastal colonisation of Australia before people then moved on to occupy the interior.
She theorises that the Aboriginal colonisers had an economy adapted to living on tropical coasts, and that the similarities between the edible tropical plants and coastal environments of the new continent and their departed homelands would have facilitated settlement. Their marine-based technology and economy – heavily reliant upon scale fish, small fish, and small animals – would not have had to change to exploit Australian coastal resources. As such the people could have gradually moved around the periphery of the continent and then expanded inland along major river and lake systems.
Bowdler suggests a slow pattern of settlement, with the dry heart of the continent occupied much later once a broadly based or terrestrial economy had developed. The people would have first had to develop techniques to hunt unfamiliar terrestrial animals such as large kangaroos and begun to use grindstones and exploit grass seeds as food. This would have occurred around 12,000 years ago.
A peripheral distribution of Pleistocene archaeological sites in Australia at the time seemed to support Bowdler’s theory. Known sites tended to be either on or near the coast or lie up major river valleys and the associated lake systems such as the Willandra Lakes in the Murray-Darling basin. However, only a small number of Pleistocene sites (15) had a known dated chronology at the time of the theory’s formulation; and little archaeological work had been done in the centre of the continent which might support or refute it.
Horton (1981: 22) has suggested Bowdler’s theory of coastal colonisation is limited by her definition of economy, especially the premise that the first arrivals had an exclusively coastal economy until c. 12,000 years ago. He also suggests that Bowdler, as with Birdsell, failed to take into account the changing climatic conditions of the greater Australian continent.
He argues that people with an adaptable all-purpose economy moved into Australia through the relatively wetter northern and eastern inland woodlands along riverine corridors and then the coast. By 25,000 years ago all but the arid core of the continent would have been penetrated. At this point Australia began to dry up and Horton believes that the megafauna became extinct, and the people retreated to the coastal regions, not moving back until the present climate was established about 12,000 years ago.
Norman Tindale (1981: 1763-97) also believed that initial migration penetrated southwards on both sides of the Great Dividing Range. Present archaeological evidence, however, supports neither this nor Horton’s theory.
Computer Modelling of ‘Super-highways’
Recent studies have reworked the various earlier theories to consider a range of biogeographical, ecological, and sociological determinants. Most notable is the 2021 computer modelling conducted by researchers at the Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage.
They argue that “human decision-making in new landscapes can lead to distinct patterns of movement that are detectable via advanced computational methods”. These methods account for the ways that geography and ecology provided constraints to, or opportunities for, movement; the demographics of the travellers; and the choices people made to explore open space.
As such, they incorporate how navigation would have been made based on prominent land features, the physiological capacity of people travelling on foot, how difficult the terrain was to traverse, and the distribution of available freshwater sources in a largely arid continent.
Putting all these different bits of information together into a mega-model, the researchers identified a network of more than 125 billion possible pathways across the continent. Each route represents the most efficient way to move from one location to another.
This was then whittled down to the most likely to have been used by first peoples. To do this, they compared all plausible pathways with the distribution of the earliest known archaeological sites on the Sahul continent. Weighted probabilities thus resulted for each path, scaling from the “most likely” to the “least likely” chosen paths.
Many of the billions of paths less likely to be chosen were discarded, allowing the researchers to focus on those that were the most probable. These most likely pathways have been called the ‘super-highways’ of Indigenous movement, while the next most likely routes have also been mapped (see video below).
Several of these super-highways correlate strongly with well-documented Aboriginal trade routes criss-crossing the country. This includes Cape York to South Australia via Birdsville in the trade of pituri native tobacco, and the trade of Kimberley baler-shell into central Australia. They also showed a striking similarity with the most common trading and stock routes used by early Europeans, which also followed the already well-known routes established by Aboriginal peoples.
The researchers have suggested such “strong similarities might suggest an extraordinary persistence of routes across the entire period of human occupation of Australia”.
In all, the results lend support to the hypothesis that movement in Sahul during this period was dispersed inland. The models do not indicate a preference for coastal environments, with people travelling along water sources and navigating by prominent landscape features.
The models suggest then that people settled in a wide range of environments and climatic zones, first in inland grasslands and rainforests, before spreading to savannas, deserts, and alpine regions. Only the most extreme arid environments of Sahul’s interior formed barriers to movement.
Another revealing insight provided by the modelling is the rapid rate that people could have spread across the entire continent of Sahul. It showed that this could have been biologically and ecologically feasible within as few as 150-200 generations (or 4370-5600 years). This is very fast by the standards of early human movement around the globe and is quite impressive considering the continent was around 11 million square kilometres at the time.
Future Implications of the Computer Modelling
The researchers are now using the modelling to look towards the future. The routes identified suggest potential target areas where archaeological evidence is likely to be found. The researchers “recommend that future archaeological prospection focus on where modern shores intersect major ancient corridors and along the identified superhighways transecting the continent”.
Many of the predicted site are not located underwater, in areas of Sahul which have since gone under the sea. This is an under-explored area of Australian archaeology, logistically challenging, although not impossible with the use of modern technologies.
The researchers’ conclusions could also have important implications on a global scale. Applying the same rules used in the modelling could shed light on the migrations of anatomically modern humans in the late Pleistocene. It could answer how these people moved out of Africa and proceeded to inhabit the rest of the planet.
The work might even have implications for humanity’s future, if large scale migrations are required due to climate change. According to the researchers, “Learning from those who have been present in Sahul from more than 60,000 years ago could help us anticipate migration patterns in the future”.
Tour of Aboriginal Australia
Travellers with an interest in learning more about the Aboriginal heritage of Australia may want to check out our various outback Australia tours.
These include visits to:
Every Odyssey guided tour is designed especially for mature and senior travellers, who want an authentic and informed experience of their destinations. Our tours aren’t the typical tourism Australia holiday – Blue Mountains, the Great Barrier Reef, and the penguin parade on Port Phillip Island. Instead, we pride ourselves on getting of the beaten path and making you think about Australia and New Zealand in new ways. We move in genuinely small groups – usually 6-12 per tour – and all tours are cost-inclusive, encompassing accommodation, attraction entries, and transport. For more information, click here, and head to this page to make a booking.
Articles about Australia published by Odyssey Traveller:
For all the articles Odyssey Traveller has published for mature aged and senior travellers, click through on this link.
External articles to assist you on your visit to Australia:
We acknowledge Aboriginal and Torres Strait Islander peoples as the First Australians and Traditional Custodians of the lands where we live, learn and work. We pay our respects to Elders past, present and emerging.