Humans Lived in Lava Tubes in Arabia
New evidence from Arabia provides new insights into regional human development and cultural change
I have always loved reading about the first and the earliest of things. Take, for example, the earliest evidence of art found at Blombos cave, the first humans to reach the Americas, and the earliest evidence of Australian Aboriginal pottery.
So, when I read about the first evidence of human occupation in ancient lava tube caves in Arabia, which are natural conduits that result after the lava has cooled, thus forming tunnels. After reading that, I had to know more.
Archaeological research in Arabia has primarily focused on the evolution and histories of local human populations and how their cultures changed and adapted to the environmental fluctuations of the past few thousand years. However, poor preservation in this arid environment hinders much archaeological research. Underground caves and lava tubes, which have been only limitedly explored in Arabia, offer promising opportunities for archaeological discovery because of their ability to shelter and preserve artifacts.
Recent archaeological excavations and surveys at and around the Umm Jirsan lava tube have revealed the first-ever evidence of human occupation of the site.
Open air vs Underground
The word ‘caveman’ is partially informed by the wrongful assumption that all our ancient ancestors were cave dwellers. This misunderstanding stems from the fact that artifacts, bodies, and generally most evidence of human life are preserved well in sheltered settings such as caves. Meanwhile, open-air sites typically preserve less well and comprise a smaller part of worldwide archaeological excavations. Since much of ancient human history is preserved in caves, it makes sense that some might think this meant our ancestors lived primarily in said caves.
However, caves were more like temporary shelters in most cases, and we have learned that much of our ancestor’s lives revolved around doing things outside of cavernous shelters.
In Saudi Arabia, most archaeological sites surveyed and excavated are open-air and thus must contend with wind erosion, temperature fluctuations, and heat exposure. These factors lead to fragmented and degraded organic artifacts (bones and plant remain). These environmental factors are even problematic within interred structures. The older the site and its artifacts, the more likely that poor preservation conditions will have degraded many, if not all, of the organic remains. Thus, inorganic artifacts, lithics, megalithic stone structures, and rock engravings remain mostly at these ancient areas.
Arabia and Human History
Humans have sporadically occupied northern Arabia as far back as the Pleistocene (2.5 million to 11,650 BP). The climate influenced this sporadic occupation; periods of hospitable climate led to human occupation, while unfavorable and harsh climates saw them disappear from the landscape again. In the later Holocene period, people could more consistently settle within the area, even during dry intervals.
Eventually, domestic livestock was introduced into the region, and later, water-harnessing technologies such as wells and dams were still in use. Eventually, oasis agriculture took hold in the Bronze Age (3000 to 1500 BC), when people in northern Arabia began sedentary lives, no longer nomadically tracking through the landscape following the herds and livestock.
In northern Arabia, anything before this sedentary agricultural period in the Bronze Age is called the pre-Neolithic (anything older than ca. 3000 BC). During this time, some of the few bits of human occupational evidence exist in rock engravings depicting hunting scenes and livestock herds, megalithic stone structures called ‘desert kites,’ and stone tools.
Despite studying the sites where these artifacts and structures occur, the timing and nature of northern Arabia's various occupational phases are poorly understood.
However, recent excavations may shed some new light on the unknown. Knowing that the numerous caves and lava tubes scattered around northern Arabia have much better preservation than open-air sites, researchers redirected their fieldwork investigations to caves and underground settings to find organic remains.
Umm Jirsan Lava Tube
The Umm Jirsan lava tube is located in the Harrat Khaybar volcanic area in NW Saudi Arabia. It is the most extended lava tube in Arabia, reaching an astounding 1481m (almost 9 miles) in length! Early work in the area reported various lithics, but more recent aerial and remote sensing work has documented hundreds of megalithic structures. Previous excavations (led by the same researchers) within the cave system uncovered bone assemblages resulting from hyenas denning in the cave. The remains are around 7000 cal BP old and include lizards, birds, gazelle, camel, cattle, wolf, hyenas, and humans. Elsewhere in the cave, more human cranial fragments were recovered.
Finding human remains means humans were in the area, but it does not indicate that humans lived in the cave. The remains were likely scavenged by hyenas who dug up nearby graves and dragged the bodies to the caves for consumption.
During the second excavation, more lithics and rock art were found alongside more bones, fragments of cloth, some round stone structures, and worked wood.
Hyenas may have brought human remains to the cave site, but only humans would and could have been the accumulator of the lithics, cloth, worked wood, and rock art. Thus providing concrete evidence that humans occupied the Arabian lava tubes.
Finds and Revelations within Umm Jirsan
Analysis of the human remains revealed that the individuals lived off a mostly protein-based diet (i.e., animal products) (74–80%), with more plants incorporated through time, likely due to the rise of oasis agriculture. The animals, specifically the livestock, seemed to have been largely dependent on the surrounding wild grasses instead of being fed with crops by humans. This remained largely the case until around the 15th to 17th centuries.
Meanwhile, the rock art analysis revealed it had quite a few similarities to Neolithic art found in northern Arabia but maybe even older in some cases, as suggested by the instances when the engravings overlap, such as in the case of panel 7, where a human figure is engraved over the pre-existing ibex. The art shows a variety of animals, including the domestic creatures the local human populations depended on for survival, like goats, sheep, and cattle; potentially, even the wild ibex could be depicted. It perhaps indicated the continued importance of the hunt for a while. Alternatively, the image is of a goat species that once existed that had a similarly characteristic pair of horns.
The human occupation of the lava tubes dates back at least 7000 years, but it may be even older up to 10,000 years. This would make the site the first documented archaeological cave with human occupation in the Arabian interior and one of the few dating back to the early-mid Holocene.
It is possible that the caves, and others like them, may have served as stop-off points for herders traveling between oases and hinterland pastures. The depictions of goats, sheep, and cattle and the abundant faunal remains of these species indicate that these herders visited the area if nothing else. The Umm Jirsan cave may have been the perfect place to rest, away from the scorching sun and screaming winds. The suggestion isn't too far-fetched because such caves are used by pastoralists even today as sheep pens. As I read these last few remarks made by the author, I could not help but imagine a human ancestor going about their day, watching the grazing herds and painting upon the lava tube cave walls; they could not have known just how fascinating their day was to day activities would one day be to their descendants.
The recent excavations and findings at Umm Jirsan provide evidence of human occupation within lava tubes. These tubes were not used as permanent residents but lay points on herding routes that provided shade and water to the passing herders and their herds. Before their use by herders, they may have served a similar purpose to traveling hunters.
The research at Umm Jirsan highlights the potential of various other caves and lava tubes in northern Arabia for archaeological endeavors. What discoveries will be made as more caves are investigated? What do you think these caves could contain? Do you have other theories on why these pastoralists and nomads sought the lava tubes?
Let me know, I would love to hear your thoughts!
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References
- Stewart, M., Andrieux, E., Blinkhorn, J., Guagnin, M., Fernandes, R., Vanwezer, N., Hatton, A., Alqahtani, M., Zalmout, I., Clark-Wilson, R. and Al-Mufarreh, Y.S., 2024. First evidence for human occupation of a lava tube in Arabia: The archaeology of Umm Jirsan Cave and its surroundings, northern Saudi Arabia. PLOS ONE, 19(4), p.e0299292.
- Stewart, M., Andrieux, E., Clark-Wilson, R., Vanwezer, N., Blinkhorn, J., Armitage, S.J., al Omari, A., Zahrani, B., Alqahtani, M., Al-Shanti, M. and Zalmout, I., 2021. Taphonomy of an excavated striped hyena (Hyaena hyaena) den in Arabia: implications for paleoecology and prehistory. Archaeological and Anthropological Sciences, 13, p.1–25.
