Up to 4000 years BCE, the region benefited from a climate very different from the one it knows today and probably close to the Mediterranean climate. The water resources were numerous with lakes in Gobaad, lakes Assal and Abbé larger and resembling real bodies of water. The humans therefore lived by gathering, fishing and hunting. The region was populated by a very rich fauna: felines, buffaloes, elephants, rhinos, etc., as evidenced, for example, by the bestiary of cave paintings at Balho. In the 3rd and 2nd millennia BCE, few nomads settled around the lakes and practiced fishing and cattle breeding. The burial of an 18-year-old woman, dating from this period, as well as the bones of hunted animals, bone tools and small jewels have been unearthed. By about 1500 BCE, the climate was already beginning to change, with sources of fresh water becoming more scarce. Engravings show dromedaries (animal of arid zones), some of which are ridden by armed warriors. The sedentary people now returned to a |nomadic life. Stone tumuli of various shapes and sheltering graves dating from this period have been unearthed all over the territory.