This Key Biodiversity Area is one of the last bastions of the wild
By Devin Murphy on October 31, 2021
The Okavango Delta is a wetland and marshy oasis in Botswana in southern Africa that seems almost mythical. Unlike nearly all deltas around the world, which are generally places where rivers and other bodies of water empty into an ocean or sea, the Okavango is an inland delta. About 2.5 trillion gallons of water carried by Okavango River, and other permanent and ephemeral rivers, empty into a dusty plain hundreds of miles from the nearest coast. The delta transforms an otherwise bone-dry landscape into a lush, busy and bustling hub of activity.
“It’s a big inland basin and swamp, and it’s hugely dynamic,” explains Chris Brown, ecologist, environmentalist and CEO of the Namibia Chamber of the Environment. “It’s changing every year depending on how the river floods. It has drier and wetter areas. It has this huge concentration of wildlife with a whole bunch of different ecotones coming together; the savanna systems, the Kalahari systems, the wetland systems, permanent water, temporary water. Permanent water wetlands are far less dynamic than partially flooded and temporarily flooded components.”
The nearly 5 million acres (2 million hectares) of permanent swamp and seasonally flooded grasslands of the delta are still largely wild and untouched by humans. Its pristine ecology attracts tourists from around the world and earned the Okavango Delta status as a UNESCO World Heritage Site. The larger Okavango River Basin, which feeds the delta, is similarly important for wildlife and people.
“It’s one of the cleanest freshwater systems,” says Brown. “The whole Okavango, apart from the extreme headwaters, runs across Kalahari sand. It’s one huge filtering system. The water is crystal clear.”
Although the crystal clear waters of the Okavango River Basin is a refuge for plants, animals and fungi, its future is less clear. ReconAfrica, a Canada-based oil company, is exploring for oil in Kavango East and West in neighboring Namibia, which is included in the Okavango River Basin.
Hundreds of wildlife species depend on the freshwater rivers that feed and the floodplains that make up the Okavango Delta. Many have timed their migrations and breeding seasons to coincide with the bounty that the floodplains bring during the winter dry season. More than 500 bird species live in the delta, as well as other groups of animals.
“You’ve got huge numbers of mammals,” says Brown. “You’ve got all the frogs, an array of different fishes and aquatic insects. You’ve got the vultures flying overhead, the big predators, the lions, the cheetah, wild dogs and so on.”
Many of those species are leading an otherwise precarious existence, with the delta being one of their last strongholds.
About 130,000 African Savanna Elephants depend on the water in the Kavango region and Okavango Delta. They move between the two areas and through several national parks within Namibia and Botswana seasonally. It’s the largest population of Savanna Elephants remaining in Africa. As elephants move across the dry Kavango landscape, they create habitat for other species, digging watering holes and pools with their tusks. The behavior has earned them the designation of a keystone species by conservationists. And these matriarchal herds use their sensitive feet, capable of detecting vibrations in the ground to communicate with each other and navigate to water sources. In 2021, the International Union for Conservation of Nature classified the African Savanna Elephant as Endangered largely due to poaching and climate change.
These monogamous cranes are named after the halo of feathers that sit atop their heads, giving them their regal appearance. Territorial pairs breed and raise chicks on the edges of flooded plains and wetlands. They mainly search for plants, insects and small amphibians and reptiles to eat. In the Okavango Delta they will follow larger herbivores, like elephants and hippos, to slurp up any animals they disturb as they trudge through the wetlands. The five-foot-tall-birds are classified as Endangered on the IUCN Red List.
Vultures are essential members of nature’s cleanup crew. They are scavengers, feeding on carrion, or the carcasses of deceased animals, in the Okavango Delta and Kavango region. They rely on their incredibly acute eyesight and sense of smell to locate prey, sometimes as far as nearly four miles away. This region's vultures include the Lappet-faced Vulture, which is Endangered, and the White-backed Vulture and White Headed-Vulture, which are all Critically Endangered.
So are Hooded Vultures, which can be found soaring over the skies of countries in southern and central Africa, including Namibia and Botswana. They are smaller than other vulture species that live across southern Africa, but they can be easily recognized by their grayish pink faces, ring of blue around their eyes and downy white feathers that cover the backs of their heads and necks. Hooded Vultures often depend on scraps left by larger animals and other species of vultures. And though they live in savannas, grasslands and forests, they often choose to live near humans. Like other vultures, they are often the victims of efforts to poison other animals, or collisions with power lines.
Less common is the Cape Vulture, which can travel as far as 60 miles away from their roosting sites, which are usually on cliff faces, in search for carrion. Although they provide a critically important function in the ecosystem, the cream-colored vultures with black-tipped flight feathers are often accidentally killed when they eat carcasses laced with poison intended for larger predators left out by farmers trying to protect their livestock. The vultures also depend on larger predators, like lions, to crunch up bones, which young vultures eat. The calcium helps keep their own skeletons healthy.
Black Rhinoceros live in the grasslands, wetlands and deserts of Namibia, including in an area where Canada-based company ReconAfrica is exploring for oil and gas. These Critically Endangered pachyderms once numbered only 2,500 in the wild, but as the result of anti-poaching efforts there are now more than 5,600 living in southern Africa. Their two horns that sit atop their snouts are made of keratin, the same substance as human fingernails. As they lumber across the savanna and wetlands of the Kavango and Okavango Delta, Black Rhinos use their hooked upper lips to grasp and hold leaves growing on trees and bushes. They also make use of mud pits in the Okavango River Basin, wallowing in mud and using it as sunscreen to protect their skin. Although they have poor eyesight, they have acute hearing and sense of smell, which they rely on to protect themselves from predators and other threats.
Temmnick’s Pangolins live in the Kalahari desert region of the Kavango in Namibia and Okavango in Botswana. They take advantage of, and live in, burrows abandoned by other species like Aardvarks. They hunt for ants and termites, slurping them up with their long tongues, in their savanna and desert homes. Pangolins are one of the most threatened groups of mammals in the world. All four species across Africa, including Temmnick’s Pangolin, are poached for their scales and meat. Their scales are used in traditional Asian medicine, though they have no medicinal value. And their meat is considered a delicacy in Asia. The demand for the animals is quickly driving their numbers down and even causing them to go functionally extinct in some areas.
Hippopotamuses live in 30 countries across sub-Saharan Africa. These stout herbivores can weigh up to 5 tons (10,000 pounds), giving them the title of the third largest land animal in the world. Though it might seem unusual for a land animal that primarily eats grass, these behemoths depend on water-logged areas, like the Okavango River Basin, for their survival. They spend much of the day swimming in rivers and swamps, shielding their delicate skin from the sun, emerging at night to eat nearly 90 pounds of grass.
Hippos are extremely adept swimmers, helped by their webbed feet and their thick blubber, which makes them buoyant. They can swim and even propel themselves through the water by using their short legs to push off the river bottom. And although they spend much of their time in the water, hippos can easily keep tabs on what’s happening above the surface and on river banks. Their eyes and ears are on the top of their heads, allowing them to stay mostly submerged while still seeing and hearing activity around them.
Many other species in the Okavango Basin, both in and out of the water, benefit from hippos living in the ecosystem. Fish and other river-dwellers eat Hippo dung that Hippos spread through the water with their flat tails. On the river banks and in grassland areas, gazelles gobble up shoots that sprout up in areas after Hippos have munched the grass down near the ground. Smaller animals use pathways created by Hippo tracks to get to the water.
Across Africa, the Hippo population has plummeted largely due to poaching. Hippos are hunted for their meat and their ivory, which has prompted the IUCN Red List to classify them as Vulnerable.
Slaty Egrets live in flooded areas, like the Okavango Delta, using the cover of tall grasses to protect them from potential predators. Their careful and deliberate walk through swampy and flooded areas belies their strategy for finding food. The gray birds shuffle their yellow
legs and feet to flush frogs and fish into the open and snatch them up. These birds, which scientists once believed were the same species as the Black Egret, have very small ranges. It’s estimated that there may be approximately 2,000 of them in the Okavango Delta and several hundred in neighboring Namibia. With such a small population and specific habitat needs, the birds are Vulnerable on the IUCN Red List.
Giraffes are the tallest animals on Earth, and are easily recognized by their long legs and necks that can help them tower to more than 18 feet tall. They use their necks, which only have seven vertebrae (the same number of vertebrae in human necks) to reach the leaves and fruit of Acacia trees. And although having a birds-eye view of the Okavango Basin is helpful to spot and avoid predators, like African Lions, being as tall as a tree can also have its disadvantages. Bending down to drink from the rivers and pools of the Okavango Delta puts Giraffes in an awkward position. They have to splay their legs and bow their necks to the water, which can make them more vulnerable to predators. To avoid constantly being in compromising positions, Giraffes have evolved to only need to drink every few days, instead absorbing water from the plants they eat. They provide a valuable warning system for other species in the Okavango Basin. Since they can see threats from so far off, other animals heed their alarm calls, which sound like snorts, and run if a herd takes off.
Giraffes are Vulnerable on the IUCN Red List largely due to poaching and habitat loss. Much of their habitat is being converted to farmland for livestock and in other areas they are hunted for their meat and pelts.
Don’t judge a cat by its size. Though the Black-footed Cat weighs up to a mere five pounds, it has a reputation as a fierce and incredibly effective predator. One study estimated that the tiny felines catch their intended prey, mostly small mammals, birds, reptiles and insects, 60 percent of the time. Their larger relatives, African Lions, are only successful in about a quarter of their hunts. The Black-footed Cat’s unrivaled predatory skills are a necessity of survival. They need to eat up to 20 percent of their body weight each day to survive. Using the cover of darkness, they leave the abandoned burrows and termite mounds they live in to escape the heat of the day in the dry savanna and grasslands of Namibia, Botswana and South Africa, for their hunting forays.
Although the Black-footed Cat has a reputation as a stealthy and effective predator, they are listed as Vulnerable on the IUCN Red List. Much of their grassland habitat is being converted into cattle pastures and they can often become the unintended target of poisoned carcasses and pesticides left for other predators.
African Wild Dogs are social canids, living in packs that patrol dry arid landscapes, like the Kavango regions in Namibia and the desert ecosystem surrounding the Okavango Delta in Botswana. The packs, which can number up to 40 dogs in areas with enough space and prey, are fairly egalitarian, with little conflict from members trying to jostle their way into a higher spot in the social hierarchy of the pack. Instead, males and females help care for pups, as well as sick and injured members of the pack. Each pack has a dominant male and female pair who are monogamous.
This cooperative lifestyle also makes African Wild Dogs precise and efficient predators. The hunting members of the pack work together to capture Warthogs, gazelles, antelopes and Wildebeest calves. Once the pack has their sights on potential prey, it’s hard for it to escape. Wild dogs are capable of running for long distances at speeds of 35
Their notoriety as hunters means African Wild Dogs are sometimes blamed for hunting livestock, which is more common prey for larger predators like Lions, Leopards and Hyenas. Retaliatory hunting combined with their savanna habitat being converted into farmland for livestock has seen Wild Dog numbers plummet. There are now about 6,500 in the wild, earning them a listing as Endangered on the IUCN Red List. The Kavango Basin in Namibia and Okavango Basin in Botswana are two of their last strongholds.
The African Lion is the king of the savanna and the Okavango Delta. The great cats can weigh between 300 and 500 pounds and are the most social species of cat, living in groups called prides. Their unique social structure helps them defend territories, and hunt and raise cubs. Females do the vast majority of the hunting, while male lions defend the pride’s territory and protect them from potential predators. Working together during carefully orchestrated hunts that involve stalking and quickly ambushing prey, Lions are capable of hunting animals many times larger than themselves, including Hippos, Water Buffalo and even Giraffes. Despite their unrivaled status as the apex predator of southern Africa, Lions never pass up an opportunity to secure a meal and will steal a kill from Hyenas, Cheetahs or other carnivores.
Their opportunistic hunting style sometimes causes conflict with humans, specifically ranchers who fear for the safety of their livestock. Large portions of Lions’ habitat has been converted into farmland over the past several decades, pushing them into smaller areas. Sometimes in retaliation for killing livestock or to prevent it, ranchers will leave poisoned carcasses that Lions eat. During the past 20 years, African Lion populations have decreased by 50 percent. They depend on healthy and bustling ecosystems like the Okavango Delta to survive.
The Cheetah is the fastest land mammal in the world, reaching speeds of up to 68 miles per hour when chasing down prey. Their semi-retractable claws, flexible spines and long tails help them balance when they put on brief bursts of speed to chase down smaller antelopes, like Gazelles and Impalas. They hunt primarily during the day when there is less competition from Lions and Jaguars. Though, they frequently are chased off their successful kills by larger cats and Hyenas.
Cheetahs have the dubious honor of being the most vulnerable species of cat in the world. One of their last strongholds is in southern Africa in Namibia and Botswana, including the Okavango River Basin. The less than 7,000 Cheetahs living across Africa, struggle to find territories large enough to support them and allow them to find mates. Their increasingly isolated and fragmented ranges exacerbate their naturally low genetic diversity, leaving them more susceptible to diseases and less resilient to environmental changes. Like all predators, Cheetahs play an important role keeping Namibia’s grassland ecosystem in balance. They help keep the number of grazing animals in check, slowing and even preventing grasslands from turning into deserts.
This story is the first part of Re:wild's Devil on the Delta blog series, an in-depth look at oil and gas drilling in the Okavango River Basin.
Devin Murphy is Re:wilds’s senior communications specialist and helps Re:wild and its partners tell stories about the work they do to protect wildlife and wildlands around the planet. Her favorite stories about conservation include fascinating and little-known species and the dedicated humans protecting them.