When did modern humans get to Australia?

The viewpoints about the origins of these peoples was once entangled with the wider debate regarding the origins of all modern humans. During the 1980s and 1990s, the two main viewpoints were the ‘Out of Africa’ and ‘Multiregional’ models. However, new fossils and improved DNA research have resulted in these models becoming obsolete. The broad consensus now is that all modern humans are descended from an African population of Homo sapiens that migrated around the world but bred with local archaic populations as they did so.

There is some debate about the role that this interbreeding had in modern human origins. The ‘Recent African Origin’ model states that modern human traits merged in Africa and while interbreeding occurred during migrations around the world, these had only minimal impacts on genetic traits of modern humans. The ‘Assimilation’ model places greater emphasis on inter breeding, claiming that some Homo sapiens traits evolved in Africa, but many new traits evolved through interbreeding with other archaic populations outside of Africa.

Old models

‘Out of Africa’ stated that the first humans to arrive in Australia came from a recent migration of Homo sapiens through South-east Asia. These people belonged to a single genetic lineage and were the descendants of a population that originated in Africa. The fossil evidence for the earliest Indigenous Australians does show a range of physical variation that would be expected in a single, geographically widespread population.

‘Multiregional’ proponents interpreted the variation found in the fossil record of early Indigenous Australians as evidence that Australia was first settled by two separate genetic lineages of modern humans. One lineage was believed to have been the evolutionary descendants of Indonesian Homo erectus while the other lineage had evolved from Chinese Homo erectus. Modern Aboriginal people are the result of the assimilation of these two genetic lineages.

The Asian Connection

Modern humans had reached Asia by 70,000 years ago before moving down through South-east Asia and into Australia. However, Homo sapiens were not the first people to inhabit this region. Homo erectus had already been in Asia for at least 1.5 million years. It is possible that these two species may have coexisted, as some dates for Indonesian Homo erectus suggest they may have survived there until as recently as 50,000 years ago. Homo erectus remains have never been found in Australia.

A second species, the Denisovans, was also know to inhabit this region and evidence shows they interbred with modern humans. Melanesians and Aboriginal Australians carry about 3-5 % of Denisovan DNA. This is explained by interbreeding of eastern Eurasian Denisovans with the modern human ancestors of these populations as they migrated towards Australia and Papua New Guinea.

Key fossil finds from Asia include

• ‘Solo Man’ - Homo erectus discovered in Ngangdong, Indonesia. ‘Solo Man’ shares similarities with earlier Homo erectus specimens from Sangiran and is considered to be a late Homo erectus. Its age is uncertain and, because its exact original location is unknown, published dates have ranged from 50,000 to 500,000 years old. If the younger age is correct, then it is possible that Homo erectus may have shared this region with Homo sapiens.
• ‘Wadjak’ - Homo sapiens discovered in 1889, Java, Indonesia. The age is between 8000 - 20,000 years old.
  Originally, this skull was thought to be about 50,000 years old and attempts were made to link this skull with the arrival of the first Australians. However, dating methods have been unable to determine exactly how old it is. It is now thought to be probably less than 20,000 years old.
• Zhoukoudian Upper Cave 101 - Homo sapiens discovered in 1933 in Zhoukoudian, China. Age is 10,000 - 25,000 years old.

Gateways into a new continent

There has always been an ocean separating Asia and Australia. At times this distance was reduced but the earliest travellers still had to navigate across large stretches of water.

For much of its history Australia was joined to New Guinea, forming a landmass called Sahul. These countries were finally separated by rising sea levels about 8,000 years ago. Genetic evidence supports the close ties between these two countries – the Indigenous peoples from these regions are more closely related to each other than to anyone else in the world, suggesting a recent common ancestry.

There are a number of likely paths of migration across Asia and into Sahul. These are based on the shortest possible route and take into consideration the land bridges that would appear during times of low sea levels. However, travel may have also occurred when sea levels were high. High sea levels would have reduced the amount of usable land and increased the population pressure. During these times it may have been necessary to expand into new areas.

Changing sea levels

Changing sea levels have significantly affected the geography of South-east Asia and Australia and the migration patterns of prehistoric peoples. During times of low sea levels the travelling distance between Timor and Sahul would have been reduced to about 90 kilometres.

Present sea levels are higher than they have been for most of the last million years. When water is locked up in the polar ice caps (known as an Ice Age) the sea level drops. When the climate becomes warmer, the ice melts and the sea level rises again.

The original seafarers

The settlement of Australia is the first unequivocal evidence of a major sea crossing and rates as one of the greatest achievements of early humans. However the motive and circumstances regarding the arrival of the first Australians is a matter for conjecture. It may have been a deliberate attempt to settle a new territory or an accident after being caught in monsoon winds.

The lack of preservation of any ancient boat means archaeologists will probably never know what kind of craft was used for the journey. None of the boats used by Aboriginal people in ancient times are suitable for major voyages. The most likely suggestion has been rafts made of bamboo, a material common in Asia.

The early occupation of Australia

The earliest dates for human occupation of Australia come from sites in the Northern Territory. The Madjedbebe (previously called Malakunanja II) rock shelter in Arnhem Land has a widely accepted date of about 50,000 years old. Reports of a date close to around 65,000 years old (Nature, 2017), which was contentious at the time, have been rebutted by Allen & O'Connell in 2020. Molecular clock estimates, genetic studies and archaeological data all suggest the initial settlement of Sahul and Australia by modern humans occurred around 48,000–50,000 years ago.

Over the last few decades, a significant number of archaeological sites dated at more than 30,000 years old have been discovered. By this time all of Australia, including the arid centre and Tasmania, was occupied. The drowning of many coastal sites by rising sea levels has destroyed what would have been the earliest occupation sites.

Recently published dates of 120,000 years ago for the site of Moyjil in Warrnambool, Victoria, offer intriguing, but unlikely, possibilities of much earlier occupation (Proceedings of the Royal Society of Victoria, 2018). The site contains remains of shellfish, crabs and fish in what may be a ‘midden’, but definitive proof of human occupation is lacking and investigations are ongoing.

The First Australians

Much of our knowledge about the earliest people in Australia comes from archaeology. The physical remains of human activity that have survived in the archaeological record are largely stone tools, rock art and ochre, shell middens and charcoal deposits and human skeletal remains. These all provide information on the tremendous length and complexity of Aboriginal Australian culture.

Human Remains

The oldest human fossil remains found in Australia date to around 40,000 years ago – 20,000 years after the earliest archaeological evidence of human occupation. Nothing is known about the physical appearance of the first humans that entered the continent about 50,000 years ago. What is clear is that Aboriginal people living in Australia between 40,000 and 10,000 years ago had much larger bodies and more robust skeletons than they do today and showed a wide range of physical variation.

Stone tools

Stone tools in Australia, as in other parts of the world, changed and developed through time. Some early types, such as wasted blades, core tools, large flake scrapers and split pebble choppers continue to be made and used right up to today.

About 6000 years ago, new and specialised tools such as points, backed blades and thumbnail scrapers became common. Significant variation between the tool kits of different regions also appeared. Prototypes for this technology appeared earlier in Asia, suggesting this innovation was introduced into Australia.

The ground stone technique produces tools with a more durable and even edge, although not as sharp as a chipped tool. The oldest ground stone tools appear in Australia about 10,000 years before they appear in Europe, suggesting that early Australians were more technologically advanced in some of their tool manufacturing techniques than was traditionally thought.

Rock art

Rock art, including painted and carved forms, plays a significant role in Aboriginal culture and has survived in the archaeological record for over 30,000 years. In age and abundance Australian Aboriginal rock art is comparable to world-renowned European cave sites such as those at Lascaux in France and Altamira in Spain.

It is probable that rock art was part of the culture of the first Australians. Its exact purpose is unknown but it is likely that from the earliest times rock art would have formed part of religious ritual activity, as is common in modern hunter-gatherer societies.

Ochre and mineral pigments

Mineral pigments, such as ochre, provide the oldest evidence for human arrival in Australia. Used pigments have been found in the earliest occupation levels of many sites, with some pieces dated at about 50,000 years old. This suggests that art was practised from the beginning of the first settlement. Natural pigments were probably used for a range of purposes including burials, cave painting, decoration of objects and body art. Such usage still occurs today.

Ochre is an iron oxide found in a range of colours from yellow to red and brown. Red ochre is particularly important in many desert cultures due to the belief that it represents the blood of ancestral beings and can provide protection and strength. Ochre is used by grinding it into a powder and mixing it with a fluid, such as water, blood or saliva.

Living sites

Archaeological evidence for living sites of Ancient Aboriginal peoples comes in a variety of forms including fishing traps and weirs, stone-base huts, possible fireplaces and remains of meals and cooking activities. The evidence indicates that lifestyle practices varied across the continent and differed depending on climate, environment and natural resources.

Shell middens are the most obvious remains of meals and are useful because they provide insight into ancient Aboriginal diets and past environments and can also be radiocarbon dated to establish the age of a site.

Important Sites

Coobool Creek

The Coobool Creek collection consists of the remains of 126 individuals excavated from a sand ridge at Coobool Crossing, New South Wales, in 1950. After their excavation, they became part of the University of Melbourne collection until they were returned to the Aboriginal community for reburial in 1985.

The remains date from 9000 to 13,000 years old and are significant because of their large size when compared with Aboriginal people who appeared within the last 6000 years. They are physically similar to Kow Swamp people with whom they shared the cultural practice of artificial cranial deformation.

Kow Swamp

This ancient burial site in northern Victoria was excavated between 1968 and 1972. The human skeletons discovered here were extremely significant because they were accurately dated between 9500 to 14,000 years ago and demonstrated substantial differences between ancient and more recent Aboriginal people.

The remains of over forty individuals have been found at Kow Swamp and include those of men, women and children. This burial site is one of the largest from this time period anywhere in the world. Many of the skeletons have a greater skeletal mass, more robust jaw structures and larger areas of muscle attachment than in contemporary Aboriginal men. The female skeletons from this region also show similar differences when compared with modern Aboriginal women.

Key remains:

• ‘Kow Swamp 1’. Human skull rediscovered in 1967 in the National Museum of Victoria by Alan Thorne and Phillip Macumber. It is dated at 10,000 years old. The skull’s original burial location was traced through police reports, and excavations at Kow Swamp began soon after.
• 'Kow Swamp 5’. This 13,000-year-old skull is one of the better-preserved examples from Kow Swamp. It has a greater skeletal mass, a more robust jaw structure and larger areas of muscle attachment than in contemporary Aboriginal men.
• ‘Kow Swamp 14’. These remains were of a male skeleton with knees were drawn up under the chest with the hands in front of the face. In other Kow Swamp burials the skeleton was fully extended. It is not known why different burial positions were used.
  

Lake Mungo

The oldest human remains in Australia were found at Lake Mungo in south-west New South Wales, part of the Willandra Lakes system. This site has been occupied by Aboriginal people from at least 47,000 years ago to the present. This age range is supported by numerous geochronological ageing techniques including Radiocarbon (C14) determinations, Optically Stimulated Thermoluminesence (OSL) and Thermoluminesence (TL). Lake Mungo has been devoid of water for the last 18,000 years and is now a dry lakebed. In the past, lower evaporation and higher runoff from the Great Dividing Range allowed the lakes to fill, supporting plentiful freshwater resources such as fish and shellfish, and making the lakes a valuable source of food for the people that occupied the area.

Key remains:

• Mungo Woman, also referred to as ‘Lake Mungo 1’ (WLH 1), was discovered in 1968. At 42,000 years old, this is the most securely dated human burial in Australia and the earliest ritually cremated remains found anywhere in the world. The cremation process shrinks bone and has made the skeleton of this originally small-bodied woman even smaller. Dr Alan Thorne reconstructed the skull from over 300 fragments.
• Mungo Man, also known as 'Lake Mungo 3’ or (WLH 3) was discovered in 1974. Unlike Mungo Woman’s cremation, Mungo Man was laid out on his back for burial and covered in red ochre before being buried in the beach sands that bordered the lake. There has been some debate over the age of this burial and while dates ranging from 26,000 to 60,000 years old have been obtained, an age closer to 42,000 years old is widely accepted.

Mungo DNA
In 2001, Australian scientists claimed that they had extracted mitochondrial DNA from ‘Mungo Man’ and nine other ancient Australians. They concluded that the genes of the modern-looking ‘Mungo Man’ were different from modern humans, proving that not all Homo sapiens have the same recent ancestor as stated in the ‘Out of Africa’ theory. These claims are controversial and could not be replicated in further studies in 2016 (PNAS 2016), and the only DNA that could be recovered from Mungo Man was European and certainly a contaminant.

Ancient DNA is easily contaminated and rarely survives for 30,000 years in conditions like those found in Australia. A complete mitochondrial genome from WLH 4, found several kilometres from Mungo Man, has been reconstructed. This individual was probably buried after the lakes had dried up in the Holocene (less than 10,000 years ago) and contains DNA that falls within the modern human range.

Cohuna

A skull was found in 1925 at Cohuna, north-west Kow Swamp, Victoria, and is undated. However, the similarity between this skull and the Kow Swamp people suggests they are both from a similar time period. This skull’s long, high, flat forehead reflects the characteristics of cranial deformation and its teeth and palate are larger than the current Australian average.

Keilor

Evidence of human activity at Keilor dates back nearly 40,000 years. Stone flakes and charcoal deposits have been found in the lowest archaeological levels.

One of the key remains from this site was that of a 12,000 year old skull discovered in 1940. It is one of the earlier prehistoric Aboriginal remains found in Australia.

Talgai

A cranium was discovered in 1884 on the Darling Downs, Queensland. It was the first Pleistocene human skull to be found in Australia. It is dated to between 9000 and 11,000 years old.

When it was found, the skull was covered in calcium carbonate, which gave the skull a deformed appearance. After cleaning, it was discovered that this skull belonged to a boy of about 15 years of age, who had died as a result of a blow to the side of the head. Features of the skull, such as the teeth and jaws, are remarkably large, but do fit within the range of variation of the Australian Aboriginal population.

One of many cultural practices that can alter the appearance of human skeletons is skull deformation. There is evidence that some Aboriginal groups did practise skull deformation in ancient times. Australian scientist Dr Peter Brown proposed that the ‘robust’ features seen in skulls such as ‘Cohuna’ and those from Kow Swamp and Coobool Creek are the result of such practices in the past. Prolonged pressing and binding of the head can produce characteristics such as long receding foreheads, flat frontal and occipital bones and lengthening of the skull.

References

Adcock, G. J., et al. (2001). "Mitochondrial DNA sequences in ancient Australians: Implications for modern human origins." Proceedings of the National Academy of Science 98(2): 537-542.

Bowler, J. M., et al. (2003). "New ages for human occupation and climatic change at Lake Mungo, Australia." Nature 421: 837-840.

Durband, A. C. R., Daniel R.; Westaway, Michael (2009). "A new test of the sex of the Lake Mungo 3 skeleton." Archaeology in Oceania 44(2): 77-83.

Heupink, T. H. S., et. al. (2016). "Ancient mtDNA sequences from the First Australians revisited." Proceedings of the National Academy of Sciences 113(25): 6892-6897.

Allen, O’Connell et al. (2020). "A different paradigm for the colonisation of Sahul", Archaeology in Oceania, Vol.55 (2020): 182–191