The Sahara was not always a desert. Through the ages, arid and humid periods have alternated in this now scorched and desolate land. Between about 5000 and 2500 B.C., for example, the western stretches of the Sahara were savanna country, roamed by such animals as the giraffes, elephants and rhinoceroses that archaeologists have found depicted in neolithic rock drawings in Western Sahara and Mauritania but which have long since vanished from this part of Africa.
