The research team, led by Alan N. Williams of the University of New South Wales and Corey J. A. Bradshaw of Flinders University, brought together an unusually broad set of evidence streams. Rather than relying on any single line of inquiry, the authors compiled ethnographic observations recorded by explorers and colonial officials, archaeological reconstructions based on radiocarbon dates from thousands of occupation sites, and genetic estimates of effective population size drawn from ancient and contemporary Aboriginal mitogenomes and genomes. Each stream carries its own biases, but the strength of the study lies in where the independent lines of evidence converge.

Technically, the team modelled the continent’s human carrying capacity using climate and net primary productivity data. They drew on high-resolution palaeoclimate reconstructions, including statistics-based global terrestrial climate products covering the late Quaternary, and combined these with vegetation productivity estimates to predict how many hunter-gatherers Australia’s environments could plausibly support. These capacity models were calibrated against a global hunter-gatherer population density dataset, which constrains expected densities using factors such as seasonality, diet composition, productivity and pathogen load. The result was a spatially explicit map of plausible pre-colonial densities across the continent, from resource-rich coastal strips to the arid interior.

Crucially, the authors found that the modelled carrying-capacity estimates and the genetics-based reconstructions agreed closely with one another, while historical and ethnographic accounts tended to fall below them. Historical estimates were shaped by observers who saw a continent already disrupted by disease and displacement, and who systematically undercounted populations in regions they never visited. By contrast, the bootstrapped median of 2.22 million people emerged from the congruence of ecological modelling and genetic demography, with confidence intervals built by resampling the underlying estimates ten thousand times. The agreement between such independent methods is what gives the new figure its persuasive force.

The implications of a pre-colonial population of this size are profound. The researchers used a stochastic demographic model to work backwards from the earliest reliable census records, which recorded only around 92,000 to 134,000 Indigenous people by the beginning of the twentieth century. For the population to fall from a median of 2.22 million to those census levels, approximately 28,200 excess deaths per year would have had to occur through the late eighteenth and early nineteenth centuries, amounting to roughly 2.06 million excess deaths in total attributable to the consequences of colonial invasion.

Those excess deaths were driven by a combination of documented forces. Lethal introduced diseases, including at least three major smallpox outbreaks, swept through communities with no acquired immunity, and the study cites companion stochastic modelling indicating rapid smallpox spread and mass mortality following colonial exposure. Measles, influenza, tuberculosis and leprosy added further burdens. But disease alone does not explain the demographic collapse. Frontier violence, recorded in the Colonial Frontier Massacres database covering 1788 to 1930, and the structural violence of dispossession, forced removal and the deliberate destruction of food and water resources compounded the mortality. The paper is explicit that these findings are confronting, and it frames the work explicitly as an exercise in truth-telling.

The demographic modelling also identifies a symbolic and ecological nadir. According to the study’s trajectory, the non-Indigenous population first exceeded the Indigenous population around 1847, which was also the year the continent’s total population reached its lowest point since before the invasion, at roughly 1.07 million people. The authors note this may represent the smallest human population on the Australian landmass in more than fifty thousand years, a startling reversal given that Aboriginal people had sustainably occupied and managed the continent since arriving in Sahul tens of millennia ago, developing sophisticated fire management and ecosystem engineering practices that shaped the landscape itself.

What distinguishes this work from earlier attempts, such as the classic twentieth-century estimates by Radcliffe-Brown and Birdsell, is its transparency and reproducibility. All data and R code are openly available through Zenodo, allowing other researchers to interrogate the assumptions, rerun the bootstrapping procedures and test alternative demographic scenarios. The sensitivity analyses show how the estimated excess deaths vary across the plausible range of initial population sizes, from one million to five million, giving readers a clear picture of where the central estimate sits within the uncertainty envelope rather than presenting a single deceptively precise number.

The study was conducted with substantial Indigenous participation and oversight, approved by the Flinders University Human Research Ethics Committee, and authored by researchers including First Nations scholars from the Gujaga Foundation and institutions across the country. The team acknowledges the Traditional Owners of the lands where they work and frames the research within reconciliation efforts. Importantly, the paper does not end with the collapse. Recent census data show that the Indigenous population of Australia has recovered strongly, surpassing 800,000 people by 2021, a trajectory of survival and renewal that the authors present as the essential counterpoint to the mortality estimates.

For demographers, archaeologists and historians, the study provides a new quantitative baseline for understanding pre-colonial Australia as a densely occupied, intensively managed continent rather than an empty wilderness awaiting settlement. For the broader public, the number 2.22 million reframes the colonial period: a society of millions was reduced to a fraction of itself within a few generations. The authors hope that rigorous, evidence-based quantification of this demographic catastrophe can contribute to national truth-telling processes, giving the scale of loss a firm empirical footing while documenting the resilience of the descendants of those who survived.

Subject of Research: Estimating the pre-colonial population size of Indigenous Australians and the demographic impact of European colonial invasion

Article Title: Large estimated size of the Australian Indigenous population before its extensive decline following colonial invasion

Article References: Williams, A. N., Tobler, R., Griffiths, B., Ulm, S., Nitschke, M. C., Bird, M. I., Ingrey, S., Saltré, F., Beller, K., McNiven, I. J., Pitt, N., Russell, L., Paterson, A., Wilson, C., & Bradshaw, C. J. A. (2026). Large estimated size of the Australian Indigenous population before its extensive decline following colonial invasion. Nature Human Behaviour. https://doi.org/10.1038/s41562-026-02571-9

Image Credits: AI Generated

DOI: 10.1038/s41562-026-02571-9

Keywords: Indigenous Australians, pre-colonial population, colonial invasion, demography, carrying capacity, excess deaths, archaeology, population genetics, frontier violence, smallpox, truth-telling, Nature Human Behaviour

The crux of this revised narrative lies in a fossilized tibia bone of a colossal ‘sthenurine’ kangaroo species discovered over a century ago in Mammoth Cave, southwestern Australia. This particular bone became a cornerstone in earlier scientific discourse because of a distinctive incision on its surface, which was interpreted in a landmark 1980 study as proof that Indigenous Australians actively hunted and butchered megafaunal animals. This interpretation, led by renowned palaeontologist Professor Mike Archer, helped cement the hypothesis that human arrival and megafaunal extinction were causally linked approximately 65,000 years ago.

However, with advances in imaging and dating technology, the validity of this interpretation has come under fresh scrutiny. Utilizing modern micro-computed tomography (microCT) scanning and refined radiometric dating techniques, researchers re-examined the leg bone and its enigmatic cut. This non-destructive, high-resolution 3D imaging revealed that the incision was inflicted not on fresh bone but on a dry, fossilized specimen already exhibiting shrinkage cracks. Such findings strongly indicate that the cut occurred long after the animal’s death, thus negating previous claims that it was a mark of butchery inflicted by humans during hunting.

This reinterpretation has profound implications for understanding the complex dynamics between Australia’s First Peoples and megafaunal species. For decades, the Mammoth Cave bone served as a ‘smoking gun’ in the debate over whether Indigenous Australians contributed significantly to the extinction of these colossal animals. The overturning of this evidence reopens scientific dialogue, casting uncertainty on human culpability and accentuating the potential roles of other environmental factors.

Complementing this bone study, researchers also examined a fossil tooth pendant belonging to the extinct marsupial Zygomaturus trilobus, discovered in the Kimberley region of northwestern Australia. This precious object was gifted by a member of the Worora Nation in the 1960s, highlighting cultural connections to prehistoric animals. Intriguingly, comparative analyses showed the tooth’s morphology and mineral composition matched fossils from Mammoth Cave, several hundred kilometers distant, suggesting the pendant was transported—potentially traded or carried—across vast distances.

The presence of such an artifact signifies a sophisticated prehistoric practice of fossil collection by Indigenous groups, likely predating European scientific interest by thousands of years. This cultural engagement with fossils hints at early palaeontological curiosity, elevating these communities to the status of some of the world’s first natural historians. It indicates that megafaunal remains held symbolic or aesthetic significance beyond subsistence and that Indigenous relationships with these extinct species were multifaceted.

While this research does not entirely dismiss the possibility that First Peoples hunted megafauna, it stresses the absence of robust, direct evidence supporting this. If systematic human predation had triggered widespread extinction, paleontologists would expect abundant signs of butchering or hunted remains within the fossil record. The solitary bone—the initial ‘hard evidence’—now reinterpreted as post-mortem modification, underscores the current evidentiary gap.

Instead, the timing and patterns of megafaunal disappearance align more closely with episodes of dramatic climate change throughout the Pleistocene epoch. Researchers suggest that environmental fluctuations, coupled with complex ecological interactions, may have played more significant roles in megafaunal declines. It remains a scientific challenge to disentangle the relative impacts of human activity and shifting climates in prehistoric extinctions.

Professor Archer and his team emphasize the importance of continuing research at other pivotal sites, like Cuddie Springs in New South Wales, where contentious but tantalizing evidence suggests a prolonged coexistence between humans and megafauna. Notably, despite this coexistence extending over tens of thousands of years, clear signs of megafaunal hunting remain elusive, lending weight to the notion that these animals were not systematically targeted to extinction by humans.

Looking forward, multidisciplinary approaches employing emerging technologies — such as more precise radiometric dating and enhanced microscopic surface analyses — promise further insights into the age and context of key fossil remains. Additionally, interdisciplinary studies incorporating Indigenous knowledge and archaeological perspectives could illuminate the cultural dimensions of fossil collecting and usage in ancient Australia.

The ramifications of this shifting paradigm extend beyond palaeontology; they invite a broader reassessment of Indigenous histories and their interactions with Australia’s natural heritage. Far from being mere bystanders or opportunistic hunters, Australia’s First Peoples emerge as the continent’s earliest custodians of palaeontological heritage, recognizing and valuing fossils in ways previously unacknowledged by Western science.

Ultimately, this research reframes the narrative of Australia’s prehistoric epoch, challenging simplistic cause-and-effect models of extinction and human impact. Instead, it reveals a nuanced history characterized by deep ecological knowledge, cultural appreciation for ancient life, and evolving interpretative frameworks driven by continuous scientific innovation.

This groundbreaking study was recently published in the journal Royal Society Open Science on October 22, 2025, under the title “Australia’s First Peoples: hunters of extinct megafauna or Australia’s first fossil collectors.” The authors declare no competing interests, and the research exemplifies how technological advancements continue to reshape our understanding of the past.

Subject of Research: Animals
Article Title: Australia’s First Peoples: hunters of extinct megafauna or Australia’s first fossil collectors
News Publication Date: 22-Oct-2025
Web References:

• https://doi.org/10.1098/rsos.250078
• https://en.wikipedia.org/wiki/Pleistocene
• https://www.tandfonline.com/doi/abs/10.1080/03115518008619643
• https://www.sciencedirect.com/science/article/abs/pii/S1040618211002266?via%3Dihub

References:

• Original 1980 study on Mammoth Cave bone butchery evidence
• MicroCT imaging and radiometric dating analysis as detailed in Royal Society Open Science article

Keywords: Paleontology, Fossils, Megafauna, Indigenous peoples, Extinction, Australia, Hunting