tag:theconversation.com,2011:/us/topics/aboriginal-migration-40744/articlesAboriginal migration – The Conversation2019-12-03T18:36:08Ztag:theconversation.com,2011:article/1278032019-12-03T18:36:08Z2019-12-03T18:36:08ZDid people or climate kill off the megafauna? Actually, it was both<figure><img src="https://images.theconversation.com/files/304383/original/file-20191129-45248-1sspxz7.jpg?ixlib=rb-1.1.0&rect=4%2C9%2C1497%2C1116&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When freshwater dried up, so did many megafauna species.</span> <span class="attribution"><a class="source" href="https://epicaustralia.org.au">Centre of Excellence for Australian Biodiversity and Heritage</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Earth is now firmly in the grips of its sixth “mass extinction event”, and it’s mainly <a href="https://theconversation.com/radical-overhaul-needed-to-halt-earths-sixth-great-extinction-event-68221">our fault</a>. But the modern era is definitely not the first time humans have been implicated in the extinction of a wide range of species.</p>
<p>In fact, starting about 60,000 years ago, many of the world’s largest animals disappeared forever. These “<a href="https://australianmuseum.net.au/learn/australia-over-time/megafauna/">megafauna</a>” were first lost in <a href="http://sahultime.monash.edu.au/explore.html">Sahul</a>, the supercontinent formed by Australia and New Guinea during periods of low sea level. </p>
<p>The causes of these extinctions have been debated for decades. Possible culprits include <a href="https://theconversation.com/climate-change-wiped-out-australias-megafauna-13966">climate change</a>, <a href="https://theconversation.com/new-analysis-finds-no-evidence-that-climate-wiped-out-australias-megafauna-53821">hunting or habitat modification by the ancestors of Aboriginal people</a>, or a <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2015.2399">combination of the two</a>.</p>
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<a href="https://theconversation.com/what-is-a-mass-extinction-and-are-we-in-one-now-122535">What is a 'mass extinction' and are we in one now?</a>
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<p>The main way to investigate this question is to build timelines of major events: when species went extinct, when people arrived, and when the climate changed. This approach relies on using <a href="https://theconversation.com/new-analysis-finds-no-evidence-that-climate-wiped-out-australias-megafauna-53821">dated fossils from extinct species</a> to estimate when they went extinct, and archaeological evidence to determine <a href="https://theconversation.com/an-incredible-journey-the-first-people-to-arrive-in-australia-came-in-large-numbers-and-on-purpose-114074">when people arrived</a>. </p>
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Read more:
<a href="https://theconversation.com/an-incredible-journey-the-first-people-to-arrive-in-australia-came-in-large-numbers-and-on-purpose-114074">An incredible journey: the first people to arrive in Australia came in large numbers, and on purpose</a>
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<p>Comparing these timelines allows us to deduce the likely windows of coexistence between megafauna and people.</p>
<p>We can also compare this window of coexistence to long-term models of climate variation, to see whether the extinctions coincided with or shortly followed abrupt climate shifts.</p>
<h2>Data drought</h2>
<p>One problem with this approach is the scarcity of reliable data due to the extreme rarity of a dead animal being fossilised, and the low probability of archaeological evidence being preserved in Australia’s harsh conditions.</p>
<p>This means many studies are restricted to making conclusions regarding drivers of extinction at the scale of single palaeontological sites or of specific archaeological sites. </p>
<p>Alternatively, timelines can be constructed by including evidence across large spatial scales, such as over the <a href="https://theconversation.com/new-analysis-finds-no-evidence-that-climate-wiped-out-australias-megafauna-53821">entire continent of Australia</a>. </p>
<p>Unfortunately, this “lumping” of the available evidence across many different sites disregards the variation in the relative contribution of different extinction drivers across the landscape.</p>
<h2>Mapping extinction</h2>
<p>In our <a href="https://www.nature.com/articles/s41467-019-13277-0">research published in Nature Communications</a>, we developed advanced mathematical tools to map the regional patterns of the timing of megafauna disappearances and the arrival of Aboriginal ancestors across south-eastern Australia. </p>
<p>Based on these new maps, we can now work out where humans and megafauna coexisted, and where they did not. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=653&fit=crop&dpr=1 600w, https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=653&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=653&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=821&fit=crop&dpr=1 754w, https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=821&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/304225/original/file-20191128-178078-mo80fk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=821&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Areas of coexistence and non-coexistence between humans and megafauna.</span>
<span class="attribution"><span class="source">F. Saltré</span></span>
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<p>It turns out humans coexisted with the megafauna over about 80% of south-eastern Sahul for up to 15,000 years, depending on the region in question. </p>
<p>In other regions such as Tasmania, there was no such coexistence. This rules out humans as a likely driver of megafauna extinction in those areas. </p>
<p>We then aligned these windows of coexistence and non-coexistence in each part of the landscape with several environmental measures derived from climate simulations over the past 120,000 years. This gave us an idea about which factors best explained the timing of megafauna extinction in each part of the landscape. </p>
<p>Despite a major effect on extinctions in areas where megafauna and people did not coexist, there was nothing at all to explain the timing of megafauna extinctions in places where megafauna and people coexisted. </p>
<p>This surprising result suggested that we had missed something important in our analyses.</p>
<h2>Connecting the dots</h2>
<p>The major flaw in our approach was to analyse each location independently of its surroundings. Our initial model had failed to take account of the fact that an extinction in one place can affect an extinction in another location nearby. </p>
<p>Once we changed our model to incorporate these effects, the real picture finally emerged. We found that megafauna extinctions in areas were they coexisted with humans were most likely caused by a combination of human pressure and access to water.</p>
<p>In the other 20% of the landscape, where humans and megafauna did not coexist, we found that extinctions likely occurred because of a lack of plants, driven by increasingly dry conditions. This doomed many plant-eating megafauna species to extinction. </p>
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<a href="https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/304380/original/file-20191129-45296-yb8dhl.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Relative importance (in %) of variables best describing the timing (first row) and the directional gradient (second row) of megafauna extinction in areas of non-coexistence (first column) and coexistence (second column) of people and megafauna.</span>
<span class="attribution"><span class="source">F. Saltré</span></span>
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<h2>Space is key</h2>
<p>This is the first evidence that tens of thousands of years ago, the combination of humans and climate change was already making species more likely to disappear. Yet this pattern was invisible if we ignored the interconnectedness of the various regions involved. </p>
<p>This might be just the beginning we need for a new, more nuanced treatment of environmental change in the deep past in other regions of the world.</p>
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Read more:
<a href="https://theconversation.com/11-000-scientists-warn-climate-change-isnt-just-about-temperature-126261">11,000 scientists warn: climate change isn't just about temperature</a>
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<p>More importantly, our results reinforce <a href="https://theconversation.com/11-000-scientists-warn-climate-change-isnt-just-about-temperature-126261">scientists’ stark warning</a> about the immediate future of our planet’s plants and wildlife. Given rising human pressures on the natural world, coupled with an unprecedented pace of global warming, modern species are facing similar ravages.</p><img src="https://counter.theconversation.com/content/127803/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Corey J. A. Bradshaw receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Frédérik Saltré and Katharina J. Peters do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A drying climate and the arrival of people together finished off Australia’s megafauna.Frédérik Saltré, Research Fellow in Ecology & Associate Investigator for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityCorey J. A. Bradshaw, Matthew Flinders Fellow in Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityKatharina J. Peters, Postdoctoral Fellow, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/961182018-05-20T19:48:57Z2018-05-20T19:48:57ZHow to get to Australia … more than 50,000 years ago<figure><img src="https://images.theconversation.com/files/218337/original/file-20180509-34038-18ofom4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sunset looking across Port Warrender to the Mitchell Plateau on the Kimberley coast. It is in Wunambal Gaambera country.</span> <span class="attribution"><a class="source" href="http://www.markjonesfilms.com.au">Mark Jones Films (with permission)</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Over just the past few years, new archaeological findings have revealed the lives of early Aboriginal Australians in the Northern Territory’s Kakadu potentially as early as <a href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">65,000 years ago</a>, from the Kimberley and Pilbara regions of Western Australia by about <a href="https://theconversation.com/cave-dig-shows-the-earliest-australians-enjoyed-a-coastal-lifestyle-77326">50,000 years ago</a>, and the Flinders Ranges of South Australia by around <a href="https://theconversation.com/the-evidence-of-early-human-life-in-australias-arid-interior-67933">49,000 years ago</a>.</p>
<p>But how was it even possible for people to get to Australia in the first place? And how many people must have made it to Australia to explain the diversity of Aboriginal people today?</p>
<p>In a study published in <a href="https://doi.org/10.1016/j.quascirev.2018.04.027">Quaternary Science Reviews</a> this week, we use new environmental reconstructions, voyage simulations, and genetic population estimates to show for the first time that colonisation of Australia by 50,000 years ago was achieved by a globally significant phase of purposeful and coordinated marine voyaging.</p>
<h2>Past environments</h2>
<p>Australia has never been connected by dry land to Southeast Asia. But at the time that people first arrived in Australia, <a href="https://theconversation.com/australias-coastal-living-is-at-risk-from-sea-level-rise-but-its-happened-before-87686">sea levels were much lower</a>, joining the Australian mainland to both Tasmania and New Guinea.</p>
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Read more:
<a href="https://theconversation.com/australias-coastal-living-is-at-risk-from-sea-level-rise-but-its-happened-before-87686">Australia's coastal living is at risk from sea level rise, but it's happened before</a>
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<p>Our analysis using new high-resolution mapping of the seafloor shows that when sea levels were 75m or lower than present, a string of more than 100 habitable, resource-rich islands were present off the coast of northwest Australia.</p>
<p>These islands were <a href="https://theconversation.com/island-hopping-study-shows-the-most-likely-route-the-first-people-took-to-australia-93120">directly visible</a> from high points on the islands of Timor and Roti and as close as 87km.</p>
<p>This chain of now mostly submerged islands - the Sahul Banks - was almost 700km long. They represented a very large target for either accidental or purposeful arrival.</p>
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<a href="https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218026/original/file-20180508-46353-ts06zx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Northwest Australia showing a now submerged string of islands between Australia and Timor/Roti. The present coastline is shown as a black line. The coastline with sea level 75m lower than present is shown as a grey line.</span>
<span class="attribution"><span class="source">Robin Beaman</span></span>
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<h2>How difficult was it to get to Australia?</h2>
<p>Combining modelled winds and ocean currents with particle trajectory modelling, we simulated voyages from three sites on the islands of Timor and Roti. This is similar to the approach used to model the movements of wreckage from the missing <a href="https://blogs.csiro.au/ecos/mh370/">Malaysia Airlines flight MH370</a>.</p>
<p>In our model, we simulated the “launch” of 100 vessels from each site on February 1 each year for 15 years. The date was chosen to correspond to the main summer monsoon period when winds are generally blowing to the east-southeast, thereby maximising the chance of successful crossings.</p>
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<a href="https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218024/original/file-20180508-46347-73zqus.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Model results for vessel launches from Timor and Roti, showing ‘accidental’ drift voyaging where only wind and currents affect movement. Yellow dots show the islands closest to Timor/Roti.</span>
<span class="attribution"><span class="source">Scott Condie/Robin Beaman</span></span>
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<a href="https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/218025/original/file-20180508-46328-hfnjgo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Model results for vessel launches from Timor and Roti, showing ‘purposeful’ voyaging simulated by paddling. Yellow dots show the islands closest to Timor/Roti.</span>
<span class="attribution"><span class="source">Scott Condie/Robin Beaman</span></span>
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<p>The results clearly indicate that accidental arrival by drifting alone is very unlikely at any time. But the addition of even modest paddling towards the Sahul Banks islands results in a high proportion of successful arrivals over four to seven days. The highest probability of a successful landfall is associated with launching points on western Timor and Roti.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/_3wrBK7rMIo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Vessel colour begins to fade after six days of voyaging, indicating likely diminishing success rates. The present coastline is shown in dark grey. The coastline with sea level 75m lower than present is shown in light grey (Animation by Rebecca Gorton, CSIRO).</span></figcaption>
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<h2>How many people did it take to colonise Australia?</h2>
<p>Researchers have long speculated about how many people originally colonised Australia. Some have <a href="https://books.google.com.au/books?id=Fp-l8IEAFHQC&pg=PA409&lpg=PA409">argued</a> that Australia must have been colonised by accident, perhaps by just a few people. </p>
<p>Others have suggested a steady trickle of colonists. Estimates of the founding population have ranged from <a href="https://theconversation.com/australias-colonisation-was-no-accident-say-the-numbers-13730">1,000 to 3,000</a>.</p>
<p>The <a href="https://theconversation.com/dna-reveals-aboriginal-people-had-a-long-and-settled-connection-to-country-73958">genetic evidence</a> shows that Australia was colonised in a single phase, perhaps at multiple locations, but with very limited gene flow after initial colonisation.</p>
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Read more:
<a href="https://theconversation.com/dna-reveals-aboriginal-people-had-a-long-and-settled-connection-to-country-73958">DNA reveals Aboriginal people had a long and settled connection to country</a>
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<p>The diversity of mitochondrial DNA lineages found in Aboriginal populations allows us to estimate the minimum size of the original colonising population. Mitochondrial DNA is only inherited from mothers.</p>
<p>Aboriginal mitochondrial DNA diversity alone represents at least nine to ten separate lineages. </p>
<p>Assuming that every mitochondrial lineage was represented in the founding population by four to five females (such as a family group containing a mother and her sister, and two daughters) the currently known nine to ten lineages would equate to around 36-50 females.</p>
<p>This is a conservative estimate, as founding populations of fewer than ten females per lineage have a low chance of long-term survival due to variations in reproductive success.</p>
<p>If an overall, again conservative, female to male ratio of 1:1 is assumed for the colonising party, the inferred founding population would be around 72-100 people. It was likely much larger (perhaps 200-300) because of the strong potential for related family groups to share similar mitochondrial lineages, which would be underestimated as a single founding lineage.</p>
<p>Clearly, a population of even the minimum estimated size is unlikely to have arrived accidentally on Sahul.</p>
<h2>What does it all mean?</h2>
<p>A lot of <a href="https://books.google.com.au/books?id=Fp-l8IEAFHQC&pg=PA409&lpg=PA409">earlier thinking</a> about how people arrived in Australia was based on the assumption that the first modern humans to sweep out of Africa and colonise the distant lands of Australia and New Guinea were somehow more limited in their cognitive and technological capacities than later humans (that is, all of “us”). </p>
<p>Therefore, models routinely assumed that people island-hopped short distances rather than making long journeys, probably ending up in Australia by accident.</p>
<p>Our results show that colonisation of Australia and New Guinea was no accident. Colonisation of Australia was more likely achieved by purposeful and coordinated marine voyaging, undertaken in the knowledge that land existed to the south of Timor/Roti.</p>
<p>The crossing to Australia was two to three times longer than the multiple previous shorter crossings required to reach the islands of Timor and Roti. This last voyage to reach Australia would have required watercraft construction, sailing and navigation technology, planning ability, information sharing and provisions to sustain an open ocean voyage over four to seven days.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/island-hopping-study-shows-the-most-likely-route-the-first-people-took-to-australia-93120">Island-hopping study shows the most likely route the first people took to Australia</a>
</strong>
</em>
</p>
<hr>
<p>Purposeful voyaging on this scale clearly required advanced cognitive, linguistic, symbolic and technological capabilities. Critically, this finding places a unique global time-stamp on the <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1834-4453.1992.tb00297.x">cognitive abilities of our ancestors</a>.</p>
<p>In the same way that we have <a href="https://www.newscientist.com/article/mg15721250-500-ancient-mariners-early-humans-were-much-smarter-than-we-suspected/">underestimated the abilities of our human ancestors</a>, we have <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1834-4453.1992.tb00297.x">underestimated the ability of early modern humans</a> to plan, coordinate and undertake large-scale coordinated maritime voyaging across open water to reach Australia. The settling of Australia represents the earliest known maritime diaspora in the world.</p>
<p>This emerging picture of modern humans with advanced maritime capabilities deliberately settling the driest continent on the planet reminds us we still have much to learn about the complexity and adaptability of the First Australians.</p><img src="https://counter.theconversation.com/content/96118/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sean Ulm receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Alan Cooper receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Michael Bird receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Peter Veth receives funding from the Australian Research Council and the Kimberley Foundation Australia. </span></em></p><p class="fine-print"><em><span>Robin Beaman receives funding from Geoscience Australia and the Qld Dept of Environment and Science. </span></em></p><p class="fine-print"><em><span>Scott Condie receives funding from a wide range of government organisations, foundations and industry. </span></em></p>The first people to make it to Australia could have navigated their way by sea crossing, reaching the north-west coastline of the island continent more than 50,000 years ago.Sean Ulm, Deputy Director, ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook UniversityAlan Cooper, Director, Australian Centre for Ancient DNA, University of AdelaideMichael Bird, ARC Laureate Fellow, JCU Distinguished Professor and Landscapes Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook UniversityPeter Veth, Kimberley Foundation Ian Potter Chair in Rock Art and Professor of Australian Archaeology, Centre for Rock Art Research and Management, The University of Western AustraliaRobin Beaman, Research Fellow, College of Science and Engineering, James Cook UniversityScott Condie, Senior Principal Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/810212017-07-19T17:01:59Z2017-07-19T17:01:59ZBuried tools and pigments tell a new history of humans in Australia for 65,000 years<figure><img src="https://images.theconversation.com/files/178587/original/file-20170718-22034-tf7mvl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Madjedbebe excavation in the Northern Territory.</span> <span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The question of when people first arrived in Australia has been the subject of lively debate among archaeologists, and one with important consequences for the global story of human evolution. Australia is the end point of early modern human migration out of Africa and sets the minimum age for the global dispersal of humans. </p>
<p>This event was remarkable on many fronts, as it represented the largest maritime migration yet undertaken and the settlement of the driest continent on Earth, and required adaptation to vastly different flora and fauna. </p>
<p>Although it is well known that anatomically modern humans were in <a href="https://www.nature.com/nature/journal/v546/n7657/full/546212a.html">Africa before 200,000 years ago</a> and <a href="http://www.nature.com/news/teeth-from-china-reveal-early-human-trek-out-of-africa-1.18566">China around 80,000 years ago</a>, many archaeologists believe that Australia was not occupied until <a href="http://dx.doi.org/10.1080/03122417.2014.11682025">47,000 years ago</a>.</p>
<p>But our research, <a href="https://www.nature.com/articles/doi:10.1038/nature22968">published today in Nature</a>, pushes back the timing of this event to at least 65,000 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178742/original/file-20170719-30196-zz9f3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists Dr Elspeth Hayes (left) with Mark Djandjomerr (centre) and May Nango (right) at the dig site.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A difficult age</h2>
<p>Together with the Mirrar Aboriginal people, our team excavated the Madjedbebe rockshelter in Kakadu, near Jabiru in Australia’s Northern Territory. <a href="http://www.nature.com/articles/345153a0">A small excavation in 1989</a> at this site had proposed evidence for human activity in Australia 60,000-50,000 years ago. </p>
<p>But some archaeologists have been reluctant to accept this age. Some pointed to the sandy deposit at the site and argued that the artefacts may have been easily moved down into older layers by trampling or burrowing animals. </p>
<p>Others said the measured ages for the archaeological sediments were not precise enough to support a date of 50,000 years, rather than <a href="http://www.tandfonline.com/doi/abs/10.1080/03122417.2014.11682025">45,000 years ago</a>.</p>
<p>Since those excavations in the 1980s, the debate has intensified. <a href="http://science.sciencemag.org/content/early/2011/09/21/science.1211177">Analysis of DNA</a> from the hair of an Aboriginal man who lived 100 years ago suggests that Aboriginal Australians separated from early Asian populations some time between 62,000 and 75,000 years ago.</p>
<p>On the other hand, <a href="https://www.nature.com/articles/ncomms14142">climate records</a> have implicated humans in megafaunal population collapse at 45,000 to 43,100 years ago, a time frame that had been presumed to correlate with humans’ arrival in Australia.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178743/original/file-20170719-20055-tk30ky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chris Clarkson and May Nango.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To make new research possible, a landmark agreement was reached between the University of Queensland (and associated researchers) and the Gundjeihmi Aboriginal Corporation representing the Mirarr traditional owners of the site. </p>
<p>The agreement gave ultimate control over the excavation to the Mirarr senior custodians, who had oversight of the excavation and curation of the material. The Mirarr were interested to support new research into the age of the site and to know more about the early evidence of technologies thought to be present there.</p>
<h2>New digs, new dates</h2>
<p>In 2012 and 2015 our team excavated an area of 20 square metres at Madjedbebe. We found artefacts in three distinct layers of occupation. </p>
<p>Among the artefacts in the lowest levels we found many pieces used for seed grinding and ochre “crayons” that were used to make pigments. Our large excavation area allowed us to pick up very rare items, such as the world’s oldest known edge-ground hatchets and world’s oldest known use of reflective pigment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=906&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=906&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=906&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1138&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1138&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178747/original/file-20170719-30196-141fkak.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1138&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Axes and grinding stones from the Pleistocene found in the excavations.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>During the excavations we recorded the three-dimensional co-ordinates of more than 10,000 stone artefacts using a laser total station. This device sits on a tripod and uses a laser and prism to record the location of artefacts and other features at millimetre accuracy. This gives a very precise record of artefact position and layering. </p>
<p>We analysed these co-ordinates to test previous criticisms that artefacts might have moved a lot in the sand. We found some broken artefacts that we could fit back together, and by measuring the distance between these pieces we can understand how far artefacts have moved. </p>
<p>We also conducted <a href="https://doi.org/10.1016/j.jas.2017.01.008">an experiment</a> to observe the movement of artefacts on the ground when people walked over them. These results allow us to respond to the earlier critics with data that point to a relatively small amount of movement, not enough to mix artefacts between the three distinct layers of occupation that we found in our excavations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178744/original/file-20170719-24356-1r4j4ld.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Excavations through many layers at the site.</span>
<span class="attribution"><a class="source" href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">Dominic O Brien/Gundjeihmi Aboriginal Corporation</a></span>
</figcaption>
</figure>
<p>During the excavation we collected many kinds of samples for specialised analyses, including more than 100 samples for dating. We used both <a href="https://theconversation.com/explainer-what-is-radiocarbon-dating-and-how-does-it-work-9690">radiocarbon dating</a> and optically stimulated luminescence (<a href="https://www.thoughtco.com/luminescence-dating-cosmic-method-171538">OSL</a>) methods to date the artefacts. Because radiocarbon dating is limited to samples younger than 50,000 years ago, we relied on OSL to help us find the ages of the lower part of the site.</p>
<p>OSL methods estimate the time elapsed since sand grains were last exposed to sunlight. Australian archaeologists have been wary of OSL methods because often in the past OSL involved sand grains measured together in a little group, resulting in ages that were not very accurate. </p>
<p>To get more precise ages, we measured thousands of sand grains individually, rather than in a group. We also had <a href="http://theconversation.com/heres-the-three-pronged-approach-were-using-in-our-own-research-to-tackle-the-reproducibility-issue-80997">another lab analyse some samples</a> to make sure our results were reliable. The result is that we have a convincing age for the settlement of Madjedbebe, and Australia, of 65,000 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178750/original/file-20170719-24356-upl3sn.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ben Marwick explaining the dig site to visitors.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>The global story of human evolution</h2>
<p>These new dates throw light on a few puzzles in the overall picture of human evolution.</p>
<p>Our ages suggest that modern humans and <a href="https://www.nature.com/nature/journal/v532/n7599/abs/nature17179.html"><em>Homo floresiensis</em> in eastern Indonesia</a> may have co-existed for 15,000 years. This means that the arrival of modern humans did not necessarily cause other ancient human-like species to become extinct. </p>
<p>If it’s the case that people have lived in Australia since 65,000 years ago, it may also be true that humans and megafauna co-existed for 20,000 years before megafauna went <a href="http://www.nature.com/articles/ncomms10511">extinct</a> across the continent. </p>
<p>Until now we knew very little about the technology and lifestyles of the first Aboriginal people. The oldest artefacts from Madjedbebe help to tell this story. They indicate that the earliest Aboriginal inhabitants of Australia were innovative people who – like humans everywhere on Earth – developed solutions to new problems and engaged in symbolic and artistic expression. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178751/original/file-20170719-10341-1es85sl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chris Clarkson (left), Richard Fullagar (centre) and Ebbe Hayes (right) inspecting Pleistocene grinding stones found at the site.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We found evidence for the mixing of ochre with reflective powders made from ground mica to make a vibrant paint. Currently, the oldest known rock art in the world is dated to <a href="https://www.nature.com/nature/journal/v514/n7521/full/nature13422.html">40,000 years ago</a> in Sulawesi (a possible stepping stone to Australia). But the abundant ground ochre and use of mica indicates that artistic expression took place in the region much earlier. </p>
<p>We also found new forms of stone tools such as edge-ground hatchet heads (and even the grinding stones used to sharpen them). These were useful in cutting bark and wood, shaping wooden tools and extracting difficult-to-obtain foods from trees. </p>
<p>The grinding stones from the site indicate a range of fruits, seeds, animals and other plants were ground up for food. These are the oldest known examples of seed-grinding stones found in Australia, if not the world. </p>
<p>In ancient fireplaces from the site we also recovered pieces of burnt pandanus nuts, fruit seeds and yams, which give us clues to the earliest plant foods consumed at the site. Some of these foods continue to be eaten today by Mirarr and other Aboriginal people in the Top End.</p>
<p>Our new ages suggest that Australia was settled well before modern humans entered Europe about <a href="https://www.nature.com/nature/journal/v479/n7374/full/nature10484.html">45,000 years ago</a>. This means that the earliest art and symbolism in Europe is of limited relevance to understanding modern technology and symbolic expression in South and Southeast Asia and Oceania. </p>
<p>Our results help to show the unique place of the eastern hemisphere, and Australia in particular, in understanding how and where modern humans appeared.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178752/original/file-20170719-10334-glpsww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chris Clarkson and Aboriginal Park Rangers at the dig site.</span>
<span class="attribution"><span class="source">Dominic O Brien/Gundjeihmi Aboriginal Corporation</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/81021/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Clarkson receives funding from the Australian Research Council, the University of Queensland and the Australian Nuclear Science and Technology Organisation.</span></em></p><p class="fine-print"><em><span>Ben Marwick receives funding from the Australian Research Council, the University of Wollongong, and the University of Washington. This work was supported in part by the University of Washington eScience Institute.</span></em></p><p class="fine-print"><em><span>Lynley Wallis receives funding from the Australia Research Council. She is affiliated with the Australian Association of Consulting Archaeologists Inc.</span></em></p><p class="fine-print"><em><span>Richard Fullagar receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Zenobia Jacobs receives funding from the Australian Research Council. </span></em></p>A new study pushes back the first known evidence of human activity in Australia – to 65,000 years ago.Chris Clarkson, Associate Professor in Archaeology, The University of QueenslandBen Marwick, Associate Professor of Archaeology, University of WashingtonLynley Wallis, Senior research fellow, University of Notre Dame AustraliaRichard Law Kelsham Fullagar, Professorial Research Fellow, University of WollongongZenobia Jacobs, Professor, University of WollongongLicensed as Creative Commons – attribution, no derivatives.