Kalahari Desert C. Mitchell

Map of the Desert.

Kahalie Desert Sunset.

Stretching around 360,000 square miles across Botswana, Namibia and South Africa, the Kalahari Desert is not a desert in the strictest sense of the word. It receives too much rainfall - between 5 and 10 inches annually. Only its vast expanses of sand, through which precipitation filters rapidly, leaving nothing on the surface, have made the Kalahari into the "thirstland" that early European settlers described.

The desert is part of the 970,000-square-mile Kalahari Basin, which includes the Okavango River Delta and other wetter areas. The basin encompasses virtually all of Botswana and more than half of Namibia. The Kalahari sand dunes, some of which stretch west to the Namib Desert, compose the largest continuous expanse of sand on earth. That is because although the Sahara Desert is larger overall, sand dunes make up only about 15% of its area.

These dunes are covered with a relative abundance of vegetation, including grass tussocks, shrubs, and deciduous trees that have evolved to make use of the area's infrequent precipitation and wild swings in temperature. In summer, the heat can top 45 degrees Celsius (115 degrees Fahrenheit); on winter nights, lows can drop to -15 degrees Celsius (seven degrees Fahrenheit).

In the wetter north and east, open woodlands exist, made up mainly of a type of acacia known as the camelthorn tree. Endemic to the Kalahari, the camelthorn is a crucial part of the desert ecosystem, manufacturing nutrients that encourage other plants to grow around its base and providing shade for animals.

The Kalahari's endemic wildlife species have adapted either to survive many days without water, or to obtain water from plants. Many reptiles also live in the Kalahari, including Cape cobras, puff adders, and rock monitors. Numerous other birds and mammals utilize the desert, but most are migratory, venturing into the Kalahari only when adequate water is present. In addition to the Hoodia cactus, other edible plants - used by both animals and humans - include creeping tsamma melons, gemsbok cucumbers, and wild cucumbers.

Cape Cobra

Fox

Hoodia cactus