A large arid region in the central part of southern Africa. The heart of the desert is in western and southern Botswana, but it extends into the eastern part of South West Africa and the northern part of Cape Province in the Republic of South Africa. In 1849 native guides took Dr. David Livingstone and William C. Oswell from the Orange River up the Molopo River valley and across the desert to Lake Ngami. They are believed to have been the first white men to cross it.
The desert has no exact boundaries, because the amount of rainfall decreases gradually, not abruptly, and consequently there is a wide transition zone between the semiarid and arid regions. Futhermore, the amount of rainfall fluctuates from year to year, so that in some years the desert is much larger than in others. The size of the Kalahari also changes with the seasons, increasing during the dry winter (June, July, and August), and decreasing during the summer (December, January, and February), when 5 to 10 inches (125-250 mm) of rain may fall. Generally speaking, however, the desert may be said to extend from 200 to 280 south latitude. The eastern edge is at approximately 260 east longitude and the western boundary merges with the dry region of Namaland and Damaraland in South West Africa. The Central Pla¬teau of South West Africa may be taken as the western boundary, but actually the dry region extends to the Atlantic Ocean, where it is known as the Namib Desert. The amount of rainfall decreases from east to west; in southeast¬ern Botswana it is about 20 to 25 inches (500-635 mm) a year, while in central and western Botswana there is about 10 inches (250 mm).
Most of the Kalahari Desert is a plateau between 2,000 and 5,000 feet (600-1,500 meters) above sea level. Much of its surface is of rock or covered by sand dunes, but vast areas have short grass and desert scrub, and there are tuberous and bulbous flowering plants that blossom after the rains. Rivers such as the Molopo in the south and the Omara in the north are ephemeral streams which dry up in the win¬ter. At the northern edge of the desert is the large Lake Ngami, 2,930 feet (893 meters) above sea level.
The desert is sparsely populated. Hunting, grazing, and subsistence farming in the wetter areas give a livelihood to
the Hottentots, Kalahari, and Bushmen who inhabit them.
Watermelons, cucumbers, pumpkins, beans, and corn may be grown.