Ever since a child, I have been mesmerised by Botswana’s Okavango Delta. Yet it’s only in my adult years that I’ve truly begun to appreciate the delicate details of this mesmerising ecosystem. The Delta is a place that is incredibly complex, held together by an intricate web of fragile elements that are seasonal and in constant fluctuation. From the wide snaking panhandle born in the heights of Angola’s highlands, to the oasis of meandering canals, yawning lagoons and surrounding grasslands – the fact that this wildlife haven even exists, within the hostile thirstland of the Kalahari, makes the Delta every bit a miracle.
The Okavango’s rich eco-system is sustained by a variety of ecological engineers, (one of these being hippos) each playing a vital role in keeping the Okavango alive. But before we chat about these incredible herbivores, you need to know a little more about the structural history of this amazing area…
Geological evidence suggests that the Okavango is the last remnant of what was once an enormous lake (Lake Makgadikgadi) that covered most of the Kalahari, incorporating the Makgadikgadi Pans. The Okavango, Chobe, Kwando and upper Zambezi waterways once flowed together as one massive river, joining the Limpopo and flowing into the Indian Ocean. But shifting tectonic plates created a rift (a continuation of the Great Rift Valley in East Africa), which led to a damming back of the giant river and created vast swamps that dried up more and more over the years, aided by climate change. This caused sand and sediment to be deposited in the Kalahari and accounts for the salty nature of the Magadigadi Pans today. Nowadays 95% of the Okavango’s water evaporates, stretching out like fingers and disappearing into the Kalahari’s sea of sand, never reaching the ocean.
Hippos (‘Kubu’ in Setswana) are incredibly important to the Okavango although not much recent research has been done to determine their present population. In 1993, C.A. Spinage concluded (from arial photographs) that hippo were declining in northern Botswana at an alarming rate of 33% per annum. Historically hippos have been hunted for their meat, teeth and hides by the Bayei who stalked them from mekoros (traditional dugouts), harpooning them like old whale hunters. When European hunters arrived they shot hippos in the name of “sport” and also used them as bait for crocodile hunting. Luckily they are now protected by reserves and a strict hunting ban that was implemented in 2014.
Hippos have a sun-sensitive skin that requires them to spend their days submerged in lagoons or permanent swamplands. Come twilight, these bulky herbivores leave to find grazing grounds, usually on nearby islands. Because of the gentle undulating topography of the swamps, islands are generally situated some distance from the hippos daytime living space and as they adventure into the night, ballet-galloping along the white sandy bottom of the Delta, they plough passages and trails. These ‘hippo highways’ keep the channels and tributaries open which prevents papyrus from clogging them up and allows nutrients and sediment to circulate and sustain the vegetation and wildlife. Hippos also spray their energy-rich dung in or near the water, which is feasted on by fish, invertebrates and other important members of the food chain.
More about the Okavango…
The Okavango can be seen from space and is the biggest wetland in Southern Africa covering an area of about 192,500 square kilometres. Before reaching Botswana, its river system flows through two other countries: Angola and Namibia and with Botswana is home to about 600,000 people of varying origins and languages. In June 2014, the Okavango became a RAMSAR world heritage site. It was about time!
This Blog Post was sponsored by Africa Odyssey with all words my own. Africa Odyssey are African travel experts who represent many of my favourite lodges in Botswana including Mombo, Jao and Vumbura Plains.