Access to stone as well as water governed where early humans lived

The Empty Quarter, the world's largest sand sea in the Arabian Peninsula, once boasted freshwater lakes and verdant oases. Yet, early humans seemed to shun these areas, according to recent research. Rather, they preferred settling near abundant supplies of stone for tool-making, rather than being near water sources. After a 1500-kilometer journey across the desert and employing computer simulations, scientists concluded that the presence of stone was the primary factor in early human habitation.

"People who live by stone tools never stray far from good stone," noted Jeffrey Rose, a researcher at the University of Algarve in Portugal. "You just really don't see Stone Age sites unless you're within a few kilometres of an outcrop." The study, conducted by Rudolf Dellmour of the University of Vienna and his team, involved examining 125 locations across the Empty Quarter for signs of ancient lakes, which were prevalent between 122,000 and 67,000 years ago.

Though evidence of ancient lakes was found at 55 of these sites, no stone tools or signs of human settlement were discovered. The researchers were perplexed by this disparity and turned to computer modeling to investigate the issue further. By mapping ancient water sources and the geology of the Arabian Peninsula, they discovered that 57% of the peninsula's water-accessible terrain lacked suitable stone for tool-making.

Moreover, prehistoric human settlements were predominantly found in areas offering both water and suitable stone. This suggests that the production of stone tools was excessively wasteful, requiring ample access to raw materials. "They weren't thinking about efficiency," Rose explained. "So, you'd have a pile of garbage produced for one spear point."