A(nother) Long Overdue Update!

Kia ora,

Those of you that have previously visited this blog have likely noticed a repeated theme - human origins - a long held interest of mine.

You possibly also have noticed that it has been a while since I last posted. In the last couple of years there have been some major changes in my life. I decided to finally take the step to pursue my interest in human origins further by moving to Melbourne, Australia to undertake a PhD at La Trobe University. The focus of my PhD research, now into its second year, is on the early archaeological record of the southern Arabian Peninsula (specifically, the modern Sultanate of Oman) and is being undertaken as part of the DISPERSE project - an international and interdisciplinary collaboration investigating the wider Arabian Peninsula’s role in the story of human evolution and early 'Out-of-Africa' dispersals. This project is co-directed by my principal PhD supervisor at La Trobe University, Dr Matthew Meredith-Williams, and is currently being funded by a Discovery Project grant from the Australian Research Council.

To be completely honest with you, Arabia was not the first place I imagined my PhD research would focus on when I started looking into what options were out there. And I am not alone in overlooking this location. Historically, the role of Arabia in the story of human evolution and global dispersals during the Pleistocene epoch (ca. 2.6 million years - ca. 11,700 years ago) has been under-appreciated and under-studied. In fact, most of the relevant archaeological work that has been carried out across wider Southwest Asia (incorporating the Arabian Peninsula and neighbouring regions to the north and northeast, such as Anatolia, the Levant, Mesopotamia and Iran) has been restricted largely to a small-ish area of less than 2000 sq. km of the East Mediterranean Levant (compared to the ca. 3,000,000 sq. km of the Arabian Peninsula).

The image above shows the general distribution of published sites across Africa and western Eurasia with evidence for human (or hominin) occupation between ca. 2,000,000 and 30,000 years ago. These sites have been drawn from the ROOCEH Out of Africa Database (ROAD). This distribution likely reflects differential research focus rather than where our ancestors actually lived. From the image it is clear that there are some areas that have historically been much more of a focus for this type of research than other areas. 

For the purposes of the present discussion, I have focused in on the area of Southwest Asia in the image below. Note the dense clustering of red markers (sites) along the eastern edge of the Mediterranean (focused on modern Israel/Palestine). By comparison, markers across the much greater expanse of the Arabian Peninsula to the southeast are much, much sparser. And the vast majority of these are only known from work that has been published since 2011! 

Today most of the Arabian Peninsula is classified as arid desert and forms part of the Saharo-Arabian desert belt that stretches from the Sahara Desert in northern Africa eastwards to the Thar Desert in India, forming one of the largest biogeographical barriers on Earth.

This is probably one of the primary reasons for the historic lack of work on the Pleistocene archaeological record of Arabia - it was accordingly assumed that there was not a lot going on in this region archaeologically this long ago because the region was not capable of supporting long term human settlement – at least until the relatively recent establishment of pastoralism (or herding) as a way of life within the last 10,000 years, during the Holocene epoch (the present interglacial, which began ca. 11,700 years ago).

The study of the earliest archaeological record of Arabia may have lagged behind that of other regions due to a prevalent assumption that the region was too arid to support sustained settlement by Homo sapiens (above right) prior to the domestication of species such as Camelus dromedarius (above left) and the establishment of pastoralism as a way of life. Photo: Riley Flood.

However, as a result of increasingly sophisticated and detailed records of the past climate we now know that much of this arid desert would have been periodically transformed by the incursion of monsoonal rainfall during the Pleistocene, which appears to have activated now inactive former river and lake systems. This would have made the biogeographical barrier formed by the Saharo-Arabian desert belt today periodically "greener" and permeable to large water-dependent African fauna, including hominins. In fact – the bones of species such as Hippopotamus have been found in association with Pleistocene archaeological sites in the Saudi Arabian Nefud Desert! (Groucutt et al., 2021).

A hippopotamus. At times in the distant past the Arabian desert was wet enough that these semi-aquatic animals lived there, alongside people. Photo by Muhammad Mahdi Karim. CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=121282994 

Some hypothesised human dispersal routes 'Out-of-Africa' along now inactive river systems in Arabia that were likely active during wetter phases in the distant past. Source of image: Petraglia et al., 2019. 

These changes have been attributed to the intensification and expansion of two of the main weather systems that affect the Arabian Peninsula today - the African Summer Monsoon and Indian Ocean Summer Monsoon. Today, these weather systems can bring heavy summer rains to the southern and southwestern peripheries of Arabia, where we can see a possible analogy for what other parts of Arabia that are now arid desert might have looked like at times in the distant past.

View of the Dhofar Mountains (southern Oman) during the summer wet season. Source of image: Rose, 2022.

Above: Photos taken during fieldwork in Dhofar (southern Oman) in October 2024. I'll bet that these are not the first images that would spring to mind when most people are asked to visualise an "Arabian landscape". Photos taken by author.

More about my PhD research to come soon ...

Thanks for reading,

Nick

References cited in-text:

Groucutt, H.S., White, T.S., Scerri, E.M.L., Andrieux, E., Clark-Wilson, R., Breeze, P.S., Armitage, S.J., Stewart, M., Drake, N., Louys, J., Price, G.J., Duval, M., Parton, A., Candy, I., Carleton, W.C., Shipton, C., Jennings, R.P., Zahir, M., Blinkhorn, J., Blockley, S., Al-Omari, A., Alsharekh, A.M., Petraglia, M.D., 2021. Multiple hominin dispersals into Southwest Asia over the past 400,000 years. Nature 597, pp. 376–380. https://doi.org/10.1038/s41586-021-03863-y

Petraglia, M.D., Breeze, P.S., Groucutt, H.S., 2019. Blue Arabia, Green Arabia: Examining Human Colonisation and Dispersal Models. In: Rasul, N., Stewart, I. (eds) Geological Setting, Palaeoenvironment and Archaeology of the Red Sea, pp. 675-683. Springer, Cham. https://doi.org/10.1007/978-3-319-99408-6_30

Rose, J. I. 2022. An Introduction to Human Prehistory in Arabia: The Lost World of the Southern Crescent. Springer, Cham. https://doi.org/10.1007/978-3-030-95667-7​

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