Structures played an important role in maintaining social connections.
New research traces 7,000 years of history in South Arabia to reveal how ancient pastoralists adapted their monument-building practices in response to changing environmental and cultural conditions.
In a study published in PLOS One, an international team of archaeologists shows how these monuments evolved as the region shifted from a humid landscape to an arid desert.
Early monuments were constructed by large groups in a single effort. But as the climate became drier and people spread out, smaller groups took over the task, often building monuments gradually over multiple visits.
“The findings show that monuments are a flexible technology that reflect the resilience of desert pastoralists in the face of a changing climate,” said Joy McCorriston, lead author of the study and professor of anthropology at The Ohio State University.
But the key role that these monuments played in people’s lives remained a constant.
Monuments maintained a shared identity
“These monuments are touchstones for human social belonging,” McCorriston said.
“As these groups became smaller and more spread out in the desert, people’s interactions with the monuments consolidates a sense of being part of a larger society.”
The research team examined 371 archaeological monuments located in the arid Dhofar region of Oman. The oldest monuments date back to between 7500 and 6200 years Before Present (BP), during the Holocene Humid Period, a time when southern Arabia received more rainfall than it does today.
The most recent monuments analyzed were built between 1100 and 750 years BP, during Late Antiquity, when the region had already become a desert.
Although many of these monuments and sites had been previously studied and classified, that earlier research was typically limited to specific times and locations, according to McCorriston.
A unified model for social resilience
“What we’ve done is take a holistic look and show how all these individual monuments were part of a larger story of how the monuments changed as the lives of the people changed over thousands of years,” she said.
The researchers did this by looking at a standard set of observations for all the monuments and developing a model that could be used in other contexts and places around the world.
For example, the model may be applicable and adaptable to assess social resilience in regions such as the Saharan, Mongolian, or the high Andes.
Stone size reveals social shifts
One of the key measurements the researchers made was the volume and size of stones used in the construction of the monuments. The earliest-built monuments in the study were Neolithic platforms, which contained larger stones. They were the largest monuments studied and were built at one time.
“The significance of the larger stones is that it takes more people to lift them. We know that it took at least seven strong men to lift the largest stones,” McCorriston said.
“These large monuments that were built in one episode could only be built early on, before the region became arid. This is when large groups of people could still come together at one time.”
Some of these larger monuments could serve large gatherings of people, where they could converge with multiple herds of cattle, and have animal sacrifices and feasts.
Smaller groups, smaller monuments
As the region became more arid and could no longer support large numbers of people nor their coming together, small groups traveled widely, going to where they could find water and places for their animals to graze.
They still had to build monuments in one episode, such as for burials, but by this time, they tended to be smaller and use smaller stones, the researchers found.
Accretive triliths show changing practices
What became more common were what are called accretive monuments, which people built over time – sometimes many years – rather than in one episode, like the earlier platform monuments.
One example of such monuments is accretive triliths. The higher number of triliths, along with the smaller stone volumes with few heavy stones, are consistent with monuments built over time by smaller, dispersed groups in an era of hyper-aridity.
These accretive monuments functioned as touchstones, allowing pastoralists to maintain connections and social resilience even as their movements and populations became more dispersed.
Building memory and meaning
“In many cases, they were building a memory. They come to a monument and add their piece, which was a replicated element of the whole. It helped people maintain a community, even with those they may rarely see,” she said.
It is impossible to say what the precise messages the monuments were meant to convey, according to McCorriston. “What we can say is that the monuments conveyed readable meanings to others who shared the same cultural context.”
It is possible, though, that some monuments were built to ensure others in a social network access to important environmental information as they came by later.
“People would need to know, did it rain here last year? Did the goats eat all the grass? Pastoralists used this technology to help absorb the risk of being in an inherently variable and risky environment,” she said. And they would need to depend on social networks for livestock exchanges, marriage partners, and rare materials, like seashells, carnelian and agate, and metal.
“That is one of the key points of what we found. Our model highlights a reliance on monuments to preserve connections and adapt socially in a changing world.”
Reference: “South Arabia’s prehistoric monument landscape shows social resilience to climate change” by Joy McCorriston, Lawrence Ball, Michael J. Harrower, Ian M. Hamilton, Sarah J. Ivory, Matthew J. Senn, Tara Steimer-Herbet, Abigail F. Buffington, Ali Ahmad Al-Kathiri and Ali Musalam Al-Mahri, 28 May 2025, PLOS ONE.
DOI: 10.1371/journal.pone.0323544
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