<P> Dromedary camels and goats are the domesticated animals most commonly found in the Sahara . Because of its qualities of endurance and speed, the dromedary is the favourite animal used by nomads . </P> <P> Human activities are more likely to affect the habitat in areas of permanent water (oases) or where water comes close to the surface . Here, the local pressure on natural resources can be intense . The remaining populations of large mammals have been greatly reduced by hunting for food and recreation . In recent years development projects have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers . These schemes often lead to soil degradation and salinization . </P> <P> Researchers from Hacettepe University (Yücekutlu, N. et al., 2011) have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat . </P> <P> People lived on the edge of the desert thousands of years ago since the end of the last glacial period . The Sahara was then a much wetter place than it is today . Over 30,000 petroglyphs of river animals such as crocodiles survive, with half found in the Tassili n'Ajjer in southeast Algeria . Fossils of dinosaurs, including Afrovenator, Jobaria and Ouranosaurus, have also been found here . The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases, and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow . It was long believed that the region had been this way since about 1600 BCE, after shifts in the Earth's axis increased temperatures and decreased precipitation, which led to the abrupt desertification of North Africa about 5,400 years ago . However, this theory has recently been called into dispute, when samples taken from several 7 million year old sand deposits led scientists to reconsider the timeline for desertification . </P>

Where is sahara desert located on the world map