A photo of art that shows an animals that was common in the Sahara when it was wet. The photo was found at Tassili in the central Sahara

The Sahara Pump Theory attempts to explain how plants and animals from Africa moved into the Middle East and then Europe and Asia.

At the time, Africa was rainier than it is today, and the Sahara was wetter, with bigger lakes and more rivers.

African rainy periods are associated with a "wet Sahara" phase, during which larger lakes and more rivers exist. This causes changes in the type of animals found in the area.