The dominant vegetation: grasses, thorny shrubs and Acacia trees, can survive long drought periods of more than ten months every year.
The remarkable nests of the weaver birds in the camelthorn trees and in other acacias are a frequent sight in the Kalahari. These inconspicuous little birds, which resemble sparrows, live in huge communal nests with a diametre of up to two metres. At any given time, hundreds of lively little birds are breeding and feeding their youngsters in such a nesting colony.
The Kalahari desert is part of the huge sand basin that reaches from the Orange River up to Angola, in the west to Namibia and in the east to Zimbabwe. The sand masses were created by the erosion of soft stone formations. The wind shaped the sand ridges, which are so typical of the landscape in the Kalahari.
Only in recent geological history, 10 to 20,000 years ago, were the dunes stabilised through vegetation, so the area should actually be called a dry savannah. Unlike the dunes of the Namib Desert, those of the Kalahari are stable and not wandering.