Kalahari Desert

The Kalahari is a very big, dry land in Africa.

It is covered in sand, and lots of the sand is red. Grass and thorny trees grow on it. Days can be very hot, and winter nights can be freezing.

The Kalahari is a huge, gently rolling plain of sand in southern Africa. Britannica says it covers almost all of Botswana, the eastern third of Namibia and the northern tip of South Africa's Northern Cape province. It is about 1,600 kilometers from north to south and is estimated at some 930,000 square kilometers.

The Kalahari is high up: all of it lies at least 900 meters above sea level. Much of the sand is red, because each grain has a thin coat of iron oxide, a kind of rust. To the southwest, the Kalahari meets the Namib, the desert along Namibia's coast.

Britannica describes the Kalahari as a large basin-like plain of the interior plateau of southern Africa, occupying almost all of Botswana, the eastern third of Namibia and the northernmost Northern Cape in South Africa; its greatest north-south extent is roughly 1,600 km, its greatest east-west extent about 600 miles (970 km), and its area some 930,000 km². In the southwest it merges with the Namib. Natural Earth's outline of the region also reaches into southern Angola.

It is a featureless, gently undulating sand plain, everywhere at 900 m or more above sea level. Bedrock appears only in kopjes, low but vertical-walled hills. Whether the Kalahari counts as a desert depends on where you stand: Britannica explains that the southwestern half receives under 250 mm of rain a year, and its potential evaporation is twice its precipitation, but the northeast receives more than 500 mm and climatically is not a desert at all, though it lacks surface water.

In the north of the Kalahari there is lots of water!

A river flows in from far away. It spreads out into a giant swamp called the Okavango Delta. Elephants, zebras and many birds come to drink.

Here is a surprise: in the dry Kalahari there is a huge wetland. Every summer, heavy rains fall far to the northwest, in the hills of Angola. The water runs into the Okavango River, which flows southeast into the northern Kalahari and spreads out into many channels, swamps and floodplains in Botswana: the Okavango Delta.

UNESCO explains that the delta's water never reaches the sea. It drains into the Kalahari's sands instead. The flood arrives during the dry season, so plants and animals time their lives to it, and large herds of elephants, buffalo and zebras gather there. After very wet years, the extra water can even flow on to Lake Ngami and the Makgadikgadi Pans.

Britannica calls the northern Kalahari's drainage extraordinary: summer rains on the uplands of central Angola feed the south-flowing streams that form the Okavango and Cuando rivers. The Okavango breaks into distributary channels in northern Botswana and feeds a vast swamp; after abnormally wet seasons, overflow fills Lake Ngami and runs east along the Boteti River to Lake Xau and the Makgadikgadi Pans, creating, in Britannica's words, an area with an excess of water in a region chronically short of it.

UNESCO's World Heritage listing (2014) describes the Okavango Delta as a low-gradient alluvial fan of about 600,000 ha of permanent swamp and up to 1.2 million ha of seasonally flooded grassland, one of very few large endorheic deltas, draining into the sands of the Kalahari Basin. Because the flood peaks in the dry winter (June and July), its biota synchronize breeding and growth with the floodwater. The delta lies within the African rift system, whose geology captured the Okavango River.

Many animals live in the Kalahari.

Gemsbok and springbok are antelopes that can live where there is little water. Giraffes and zebras live in the north. Lions, cheetahs and ostriches live there too.

The Kalahari is greener in the north and drier in the south, and so are its animals. Britannica says the dry southwest has only scattered tough shrubs and short grass, the center has scattered acacia trees, and the north has open woodlands, palm trees, thorn bushes and big baobab trees.

Even in the dry south, many animals stay for much of the year without any pools to drink from: springbok, wildebeest and hartebeest, sometimes in great herds, and gemsbok, a kind of oryx, eland, kudu and the little steenbok. The north is home to giraffes, zebras, elephants, buffalo, lions, cheetahs, leopards, African wild dogs, hyenas, warthogs and lots of birds.

Deep sand shapes the vegetation, Britannica explains: shallow-rooted perennials cannot survive, but fast-growing annuals set seed after good rains, and trees whose roots reach permanently moist sand do well. The southwest has scattered xerophytic shrubs and short grasses; the centre, scattered acacias; the north, open woodland, palms among thorn brush and forests up to about 15 m tall, including the baobab. Kgalagadi Transfrontier Park, which Britannica describes as largely reddish dunes with acacias in the riverbeds, has quick grass, gemsbok cucumber, driedoring and raisinbush as forage.

In the south, springbok, wildebeest and hartebeest (occasionally in great herds), gemsbok, eland, kudu, steenbok and duiker persist for long periods without surface water. The north supports giraffe, zebra, elephant, buffalo, roan, sable, tsessebe and impala, with lions, cheetahs, leopards, wild dogs, jackals, hyenas, warthogs, baboons and ant bears. UNESCO adds that Botswana holds the world's largest elephant population, about 130,000, with the Okavango Delta at its core.

Many families live in villages in the Kalahari.

They keep cattle and goats and grow corn and pumpkins. Some San families once lived by gathering wild plants and hunting. At Tsodilo Hills, people painted animals on the rocks long ago.

People live across the Kalahari in many different ways. Britannica explains that in remote areas many families live in villages of 200 to 5,000 people, often in huts with mud walls and thatched roofs. Villages are built near wells or boreholes, because water is scarce. Cattle are very important, and goats give milk and meat. Most households grow corn, sorghum and pumpkins.

The San, called Basarwa in much of the region, are one of the Kalahari's peoples; Britannica calls the Bantu-speaking groups relative newcomers who arrived from the late 1700s. Some San groups lived as hunter-gatherers until the 1970s, gathering wild plants and hunting antelope, and moving camp every few weeks. Today few still live that way. At the Tsodilo Hills, UNESCO counts more than 4,500 rock paintings, and people have used the hills for over 100,000 years. In 1971 a big diamond mine opened at Orapa, in Botswana, and mining and tourism now bring jobs.

Britannica describes a population chiefly of Bantu speakers (the Tswana, Kgalagadi and Herero, who arrived from the late 18th century onward, the Herero as refugees from the German-Herero conflict of 1904 to 1907) and Khoisan-speaking San, with a small number of Europeans. Settlement is limited to wells and boreholes; cattle are the basis of the economy, and Britannica warns that poorly managed grazing causes pasture loss and desertification. Diamond mining began at Orapa in 1971.

Among San groups that lived as autonomous foragers until the 1970s, the G/wi of the Central Kalahari were intensively studied: bands of 5 to 16 households held territories of 300 to 400 square miles, relied mainly on eight staple food plants, moved camp every three or four weeks and split into households during the lean winter. Few San now live by foraging, and Britannica notes that many were resettled, often against their will, by Botswana's government from the Central Kalahari Game Reserve to villages outside it. At the Tsodilo Hills in northwest Botswana, a World Heritage Site since 2001, UNESCO records more than 4,500 rock paintings in only 10 km² and human use of the hills for over 100,000 years.