The following is an extract from an article first published in Agora magazine (HTAV).

According to the Australian Curriculum: History, the Ancient World falls neatly into a bracket of time that began approximately 60,000 years ago and ended 650 years ago. The Ancient World, and in particular Ancient Australia, is not as straightforward as this timeframe suggests. It has deep and complex roots that stretch back even further.

About 100,000 BP [1], when modern humans migrated out of Africa and moved into regions throughout the Middle East, the global climate was quite different to what it is today. Arid zones were more extensive, with desert regions advancing and pushing people out of previously habitable areas. Some people may have moved east into Asia, some north into Europe, and others into Sub-Saharan Africa, to escape the dry and windswept terrain [2]. Huge amounts of water became trapped in the polar ice caps and in large glaciers, causing the oceans to recede and the climate to cool down. Vast tracts of land that are underwater today were exposed during these cooler phases, making it easier for humans to spread out, a journey of exploration that averaged an advancement of one to four kilometres per year.

As humans travelled into Southeast Asia, more than 60,000 years ago, and Europe, more than 40,000 years ago, they also came face to face with another species, Homo neanderthalensis, or Neanderthals. Modern humans interbred with Neanderthals and, by doing so, appear to have inherited a helpful gene from them that boosts the immune system [3]. Geneticists have suggested that people with European descent may have around 2 to 4% Neanderthal DNA [4]. People from other parts of the world, such as Sub-Saharan Africa, do not usually have any Neanderthal DNA.

Tests conducted using genetic signatures found in skeletal remains have revealed other intriguing links. While working in a Siberian cave in 2010, archaeologists discovered a new species closely related to humans. The evidence for this new species initially relied on a tiny fragment of finger bone no larger than a fingernail. Later, a toe bone and two teeth were also found. The archaeologists named these people Denisovans after Denisova Cave, where the skeletal remains were uncovered. Archaeologists also found evidence that Neanderthals, Denisovans and modern humans had all occupied the site about 40,000 BP.

Geneticists have already found evidence that some modern humans interbred with Denisovans, just like they did with Neanderthals, and people with Denisovan ancestry share 5 to 7% DNA with this human cousin [5].

When people travelled from Asia to Australia about 50,000 BP, the sea levels were 80 metres lower than what they are today [6]. Even so, the journey would have been at least 100 kilometres, suggesting that it was either a terrible accident of misdirection, or else a deliberate attempt to reach unknown shores. Perhaps a small fishing group was swept out to sea and marooned on strange and unfamiliar shores. Or else people saw smoke on the horizon, a result of lightning strike bushfires, and decided to investigate.

Endnotes

[1] BP = years before present

[2] The Australian Museum provides a summary of migration patterns out of Africa and into Australia, as well as a comprehensive overview of Ancient Australian ancestry, technology, lifestyle and chronology: http://australianmuseum.net.au/The-spread-of-people-to-Australia/

[3] The inherited Neanderthal gene and its effects are explained in greater detail here: http://www.sciencedaily.com/releases/2013/11/131122084405.htm

[4] However, the idea that Neanderthal DNA gave some humans lighter skin and hair is a myth. Skin pigmentation was determined by latitude. For more information, see: http://mbe.oxfordjournals.org/content/30/1/24

[5] National Geographic has a useful article about the discovery of the Denisovans: http://ngm.nationalgeographic.com/2013/07/125-missing-human-ancestor/shreeve-text

[6] This interactive map of Sahul demonstrates what the coastline would have looked like at various points in the past: http://sahultime.monash.edu.au/explore.html