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Early human settlement in Yemen presents us with problems that are difficult to resolve. The complexity of the issue is clearest when we consider the gap in the archaeological record when a previously settled Yemen was seemingly empty of inhabitants. What happened to the first settlers? If we know that they came from Africa during the Lower Paleolithic period and disappeared at some point during the Middle Paleolithic period, then we face the puzzling fact that in the Upper Paleolithic era, a new, more organized and widely dispersed population appeared. Researchers have turned this mystery into a special inquiry about the identity of these artist hunters, whose traces we find in the archeological record without any idea of who their immediate ancestors were. 
Imaginary image of two men trying to ignite fire. image courtesy of Abeer al-Baredah
Habitats and environments
Fieldwork shows that our recent ancestors’ settlements took the same form found in a wide variety of regions throughout the world at this time. Though Yemen was heavily forested during this period, our ancestors were not, as some have suggested, forest dwellers.  Throughout most of the Holocene period, they have preferred a nomadic lifestyle, in valleys and grasslands, at river mouths and along lakeshores, all areas that had similar flora and fauna to that found in East Africa. Humans were found in four types of dwelling: rock shelters, which were the basic form of shelter used by hominid groups; caves, used to protect children and store food, as well as to stage communal ritual gatherings ; tents, which functioned as temporary bases for hunters looking for food and as lookout posts for observing and tracking the movement of prey and hostile human groups, and which would usually be erected at a set distance from the primary shelter to ensure it was properly protected; and hides, which were used as temporary food silos or to ambush prey, before returning to the tent or primary shelter at the end of the hunting expedition. 
Throughout the Paleolithic era, our ancestors chose to construct permanent settlements in temperate, semi-equatorial habitats, where there was a steady supply of food. Hot or jungle-like environments were home to nomadic populations; in these regions food was either scarce or there was seasonal variation in its supply. 
Foragers and nomads
The first pioneers from Africa split up, with some moving inland onto the coastal plain and some groups making progress towards the mouths of valleys that descended from the rocky uplands, such as Rima, Mawr, Siham and Surdud, where there was fresh water and rich pasture and many animals that could be hunted, such as buffalo and wild donkeys. Here they foraged for fruit and hunted. We find the same thing in the uplands, where Yemen’s biggest rivers flow, as well as the areas around the Ramlat Al Sab’atayn desert, which was thick woodland at the time. They built their settlements in the uplands, as well as in the Eastern lowlands, where human habitation dating back to the Pleistocene period was discovered thanks to early efforts by the British archaeologist Gertrude Caton-Thompson (expeditions took place in 1938 and 1953). 
The population of the period was divided into two distinct societies.
Hunter-gatherer: A form of social organization practiced by the majority of humans at the time, it tended to be more settled and stable thanks to efficient strategies for the acquisition and storage of food. These groups relied on collecting nuts, seeds and fruit in the verdant valleys and hunting animals in the grasslands and forests. Occasionally they would incorporate riverine food sources into the diet. The lifestyle generally adopted by these hunter-gatherers was based on a collective of small groups, perhaps family-based, living in rock shelters and caves from which they set out on hunting expeditions, from which they might return with fruit and seeds or, if the other residents of their shelter were particularly lucky, the carcass of a buffalo. 
Itinerant hunters: These groups were more widely dispersed and less organized, and were perpetually on the move in search of food. Members of these groups would eat whatever they found through daily foraging, since they did not store food. The researcher Marie-Louise Inzan  believes that in the Ramlat Al Sab’atayn area, Paleolithic humans were essentially nomadic hunters. During the Lower and Middle Paleolithic eras, some groups appear to have practiced cannibalism. There have been a number of archaeological digs which have exposed human mass graves, left by hunters as they went off to occupy the European landmass. 
The Middle Paleolithic: Mass exodus or mass extinction?
Neolithic dwellings. Photograph by Marie-Louise Inzan
Around 38,000 BC, Yemen’s climate became much drier, an arid period that lasted until approximately 12,000 BC. Rainfall decreased, the lakes evaporated, green grasslands turned into dunes, rivers dried up at the source, woodlands disappeared from the mountains and rainforests from the plains. This harsh environment is taken as conclusive evidence by many specialists that Yemen cannot have hosted prehistoric human settlements. But the Yemeni climate of today is if anything even more arid, and despite this vast areas of the country’s uplands remain verdant and rainy and provide habitats for equatorial fauna, such as baboons and the Arabian leopard. The onset of this arid period during the Middle Paleolithic also coincides with the period during which there is no sign in the archaeological record of human presence in Yemen. Where did Yemen’s population go during this gap?
The Upper Paleolithic: Artists who tamed animals
With the advent of the Upper Paleolithic period, a wetter climate returned and new settlers appeared in Yemen, living in rock shelters near rivers and lakes. These settlers hunted and fished, domesticated animals and created rock art, and developed new technologies for sharpening stone implements, as can be seen in the production of three-sided arrowheads.
The hunter-gatherers of this period were more diverse and better organized than their forebears from the Lower Paleolithic period. They established pyramidal decision-making structures within their communities, and built up stores of surplus food, which they used to barter. They also traded goods over long distances, including luxury items made from stone, such as jewelry, whistles, statuettes and other carvings . In general, Yemeni settlements of the period were organized around hunting, as demonstrated by the animal remains found at the sites in question. These remains, as well as rock art depicting fauna such as gazelles, wild cattle, ostrich, lions and now extinct species such as pelerovis (buffalo) and bison are evidence of a wetter climate. It is worth mentioning that wild donkeys were hunted in increasing numbers, especially on the coastal plain, from around the 7th to the 6th millennium BC.
A hunter of the tropics community, imaginary image courtesy of Abeer al-Baredah
On the uplands, settlements have been found in rock shelters situated close to ancient water channels, thanks to the fieldwork and surveys carried out by Michel-Alain Garcia and Madiha Rashad . In Saada, the existence of at least two separate periods during which lakes were present has been confirmed, as well as the existence of an ancient lake on the outskirts of the Rida district, north of Sana’a, that existed around 5,400 BC. These discoveries confirm the presence of continuous habitation in the Yemeni highlands throughout the Holocene period.
In the lowlands, the discovery of ancient riverbeds and lakebeds in Jawf/Hadramawt has led to the unearthing of ancient human settlements in desert regions that were formerly low-lying grasslands fringed by the lakes of the Empty Quarter. Traces of ritually assembled rock piles have been found in Ramlat Al Sab’atayn by ancient lakebeds. Though the lakes in Ramlat Al Sab’atayn disappeared in the 7th millennium BC, the Jawf/Hadramawt River did not run completely dry, since its source was in the Yemeni highlands which remained extremely wet for the first 3,000 years following the onset of aridity in the region . The fact that the river continued to flow down into the desertic lowlands during this period explains the emergence of ancient polities (e.g. Ma’in, Saba, Qataban and Hadramawt) in these deserts around 3,000 BC.
On the Red Sea coast, 126 separate sites have been identified from the Upper Paleolithic period: settlements containing large deposits of stone tools and stonework, as well as the seashells of species that require completely different habitats compared with that offered by the present day climate. To summarize, fieldwork has shown that these settlements housed hunter-gatherer groups which settled the coast during the Holocene era, fishing the ocean and foraging for shellfish. The presence of large quantities of wild donkey bones at the sites points to an increased focus on this form of hunting. 
In terms of agricultural activity in Yemen, extant rock art provides no direct evidence of agriculture being practiced during the Upper Paleolithic era, but we can say that it must have been contemporaneous with the domestication of cattle and donkeys after 7,000 BC . In any case, the start of the Bronze Age saw the beginning of another arid period, which lasted through to the 2nd millennium BC: the human population responded, not by vanishing, but by developing complex societies. They issued laws, forged bronze statues and built the richly decorated temples and palaces that we see today, standing proud and alone amid the desert sands: these markers of civilization represent just one chapter in our ancestors’ battle against nature.
1. Madiha Rashad & Marie-Louise Inzan, The Art of Rock Paintings and Settlement of Yemen in Prehistoric Times, 2009, p.140
2. Lewis R. Binford et al. Willow Smoke and Dogs’ Tails: Hunter-Gatherer Settlement Systems and Archaeological Sites, The Society for American Archaeology, 2008, p.13
3. Jennifer Viegas, Music and Art Mixed in the Stone Age, ABC Science, 2008
4. Lewis R. Binford et al. Willow Smoke and Dogs’ Tails: Hunter-Gatherer Settlement Systems and Archaeological Sites, The Society for American Archaeology, 2008, pp.1-19
5. Lewis R. Binford et al. Willow Smoke and Dogs’ Tails: Hunter-Gatherer Settlement Systems and Archaeological Sites, The Society for American Archaeology, 2008, p.14
6. Rémy Crassard, The Middle Paleolithic of Arabia: The View from the Hadramawt Region, Yemen, 2010, p.152
7. Lewis R. Binford et al. Willow Smoke and Dogs’ Tails: Hunter-Gatherer Settlement Systems and Archaeological Sites, The Society for American Archaeology, 2008, pp.1-19
8. Madiha Rashad & Marie-Louise Inzan, The Art of Rock Paintings and Settlement of Yemen in Prehistoric Times, 2009, p.32
9. Lin Edwards, Evidence unearthed of possible mass cannibalism in Neolithic Europe, Phys.org Science News, 2009 (https://phys.org/news/2009-12-evidence-unearthed-mass-cannibalism-neolithic.html)
10. William K. Stevens, ‘Life in the Stone Age: New findings point to complex societies’, The New York Times, 1998
11. Rémy Crassard & Lamya Khalidi, De la pré-Histoire à la Préhistoire au Yémen, 2008, p.4
12. Anne-Marie Lézine et al. Centennial to millennial‑scale variability of the Indian monsoon during the early Holocene: A sediment, pollen and isotope record from the desert of Yemen, pp.235–249
13. Ibid, p.5
14. Madiha Rashad & Marie-Louise Inzan, The Art of Rock Paintings and Settlement of Yemen in Prehistoric Times, 2009, p.25