The Kalahari occupies much more than Botswana. Its northern most borders are to be found in Angola. It stretches west into Namibia, and south into South Africa.
In Botswana, the Kalahari is divided into northern Kalahari and central Kalahari. The north is made up of a number of major salt pans – Makgadikgadi, Nxai, Ntwetwe and Sua – as well as half a dozen smaller pans. Makgadikgadi and Nxai are national parks, while Sua’s north-eastern tip is Nata Sanctuary.
The Central Kalahari is contiguous with northern Kalahari, and the best of it - the Central Kalahari Game Reserve (CKGR) – lies west and south-west of the main pans. It is the world’s second largest reserve, and covers 52,800 km2.
Given the fact of its levels of rainfall, the Kalahari is not a desert in the truest sense of the word. It has a wet season and a dry season, with the rains in the north beginning in December and finishing in March. The fauna ranges from sweet grasslands to acacia scrub, with a band of riverine woodlands exploiting the river Boteti’s water-table to the west. During and immediately after the rains – March and April - the pans’ waterholes are full, the grasslands green. However, apart from the Okavango, there is no permanent source of standing water in the Kalahari, and rainfall levels are erratic, and decrease the further south one goes. As a rule of thumb, and until recently (see below), the pans receive in the region of 450mm of rain a year, while the central Kalahari gets around 250 – 300 mm of rain a year. These levels can drop to 170 mm per annum in bad years, and are general to areas south of the CKGR, where the wet season is much shorter. Temperatures during the wet season range from 20 - 45°C, making the nights warm, the day’s uncomfortable.
Winter sets in around May. Temperatures drop considerably, the nights are very cold (occasionally below freezing), the days averaging out at around 23 to 25°C. There is virtually no rain between May and October, though temperatures begin to rise again in September.
Despite the rains, the cover during the Kalahari’s wet season is negligible, and so – contrary to most other wildlife habitats - game viewing is invariably good. Everything, however, is decided by the quality of rain, and also by that of the terrain. Depending on their soil type and salt levels, the pans are either sterile, or able to support grasses, acacia and umbrella thorn. Makgadikgadi pan itself, therefore, is good only for birds, with flamingo, white and Abdim’s stork, raptors and smaller birds adding to resident populations, while Nxai is excellent for for both birds and animals. However, the grasses and scrub surrounding the Makgadikgadi pans get progressively good the further one gets from them, and both national parks are seasonally flooded with zebra, wildebeest, impala, springbok, gemsbok, kudu, eland and hartebeest, attracting black maned lion, cheetah, striped and brown hyena and even wild dog. The Boteti’s woodlands and seasonal water sources are good for zebra, wildebeest, leopard and lion, and is stacked with game at the height of winter. Further south, great herds of springbok and gemsbok arrive in the CKGR, their numbers further bolstered by hartebeest, giraffe, ostrich and eland, all of which attract the attentions of lion, hyena and cheetah.
During the winter months, all but desert specialists travel west and north in search of water. The largest residential game is the remaining springbok, gemsbok, leopard, brown hyena, black maned lion, cheetah and even leopard. These animals occur in low densities and are difficult to sight. Lions operate solo, or in pairs, springbok and gemsbok disperse across the area in small clumps. Such behaviour chimes well with a hostile habitat, and the animals’ dry season behaviour is at odds with the norm because their environment demands it. At this time, travellers to the salt pans or to the CKGR will not be going there for the game, but rather for the experience.
This said, the Kalahari appears to have entered – along with northern Botswana - a new wet cycle.The Boteti River is once again in flood - for the first time since 1991. In September 2010 it reached the borders of Makgadikgadi, and by March this year (2011) it had reached Sukwane. In previous years, the Boteti flowed into the Makgadikgadi, and looks set to do so again. If the rising rainfall and flood levels continue, the Boteti will area attract greater numbers of migrating herds, including elephant, which currently occurs sporadically in the Kalahari.