The Pans in a Nutshell
The Sowa (Sua), Nxai and Ntwetwe Pans together make up the 12,000-sq-km Makgadikgadi Pans. While Salar de Unyuni in Bolivia is the biggest single pan in the world, the Makgadikgadi network of parched, white dry lakes is larger. Ancient lakeshore terraces reveal that the pans were once part of a ‘super lake’ of more than 60,000 sq km that reached the Okavango and Chobe Rivers to the far north. However, around 10,000 years ago, climatic changes caused the huge lake to evaporate, leaving only salt behind.
Africa's Unknown Migration
Less known than the vast congregations of wildebeest in the Serengeti, Botswana's epic zebra migration is one of Africa's grandest and most underrated spectacles.
For much of the dry season, particularly from May or June to October, the more-than-25,000 zebras that inhabit the Makgadikgadi and Nxai Pans National Park gather together close to the only permanent water sources in the region, in the far west of the salt-pan network. In recent years that has meant along the Boteti River, which marks the western boundary of the Makgadikgadi Pans section of the park.
When the rains begin to fall in Botswana in November or December, the zebras, accompanied by smaller numbers of wildebeest, migrate east across the pans – with water now plentiful across the pans, the herds are no longer trapped in the west and can roam more freely. The rains are also usually when zebra mothers give birth – zebra foals can walk within an hour of birth, a necessary adaptation given the fact that lions, hyenas and other predators stalk the herds.
By April and into May, the herds have largely returned to the Boteti River, although some remain in the east into June.
The Lions of Makgadikgadi
No one knows quite how many lions inhabit the Makgadikgadi and Nxai Pans National Park – the closest that scientists come to knowing is a lower estimate of 50 and an upper limit of no more than 200. In the dry season (roughly April to October) these lions are concentrated in greatest numbers at the western limit of their range, close to the massed herds of herbivores along the Boteti River. When the rains come and the herds disperse, the lions follow suit. Thus it is that, having adapted to the meagre resources of the northern Kalahari, the Makgadikgadi lions cover far greater distances than lions elsewhere where prey is plentiful. They also live in smaller, more mobile social groups.
But perhaps their greatest adaptation is one that suggests that Makgadikgadi's lions are, it seems, rather clever. Between 1993 and 2008, the Boteti River all but dried up, prompting wildlife to cross the riverbed and enter the human-dominated world of villages and cattle posts. When the lions attacked domesticated livestock, conflict was inevitable. In response, the lions studied by one scientific project adopted a remarkably sophisticated set of strategies for avoiding human beings and their retaliation.
For a start, lions rarely moved any closer than 3km to cattle posts and whenever they killed a cow or goat, it was, on average, 4.5km from the nearest cattle post. More than that, lions avoided human-inhabited areas between 6am and 8pm – the time of the day when human beings were most likely to be out and about. Most surprising of all, the study found that lions passing through human-dominated areas moved at a normal lion speed until they reached an uncannily accurate distance of 6km from the nearest human settlement. At this point, the lions accelerated. Once past the danger, they slowed down again and continued on their way.