Chobe’s river horses

Along the Chobe river between the rapids below Kasane up river to Serondela is home to numerous pods of hippos. The river is flowing all year round which is ideal for them. The high water period is around May-June each year when the flood waters come down from Angola. Hippos do not swim but rather walk, prance, and even “fly” underwater. They can float or sink by controlling their breathing and body position. Parts of the hippo’s skeleton have very dense bones. This bone structure acts as a form of ballast to enable them achieve neutral buoyancy underwater. They are able to further regulate their buoyancy by controlling their breath. Breathing out creates negative buoyancy.

“Everything you see exists together in a delicate balance.” ~ The Lion King

Hippopotamuses get their common name from the ancient Greeks and which literally translates into English as river horse.

“It’s not what you look at that matters, it’s what you see.” ~ Henry David Thoreau

Female hippos are highly protective of their calves even against much bigger male hippos. We found many hippos out of the water but this was because we were on the Chobe in June which is mid-winter in the southern Africa. During the day when the sun is blazing, hippos spend most of their time in the water to keep cool and prevent them from sunburn. They do like to lie in mud baths next to the river which offers some protection from the sun. Hippos also produce a red fluid which is a deep red mucus-like secretion which helps to control their body temperature and acts as a potent sunscreen and antibiotic.

This looked to be a young male trying to mount a large female hippo with red-billed oxpeckers in attendance. Hippos tend to fight a lot and many have scratches and cuts on their thick hides which the oxpeckers clean up. This young male did not look like he was making the slightest impression on the dozing female. It was winter in southern Africa so the hippos spend more time than usual sunning themselves on dry land to warm up.

Hippos usually mate in the water. The female hippos are often forcibly submerged in the water by the male hippo for most of the mating process. She needs to come to the surface at times to breathe. In some cases, although very rarely, the hippos may choose to mate on land.

 A hippo can run at 30 kilometres per hour and will charge anything that gets in its way, especially if you are between it and its place of safety, which is the water. We had one incident along the Chobe river several years ago when we got between the water a dozing bull hippo. He was dosing about 40 metres from the water’s edge in the grass. We stopped next to the bank to photograph some waders. We were between the hippo and the water but checked to ensure the bull hippo was relaxed and dozing. It was not until Lou Coetzer, our CNP Safari guide, shouted to the boat driver to get out of the way as quick as possible when we turned to see the bull hippo in full charge toward the boat. We made it but a matter of metres. In our shaken state, we were reminded never to be complacent. When hippos run for the water it does provide photographers with opportunities to capture spectacular splash shots as they charge into the water.

“Hippos always have the right of way, except when an elephant crosses its path.” ~Mike Haworth

There were other times when we were slowly boating through the thick matt of water lilies and water grass when out of nowhere a hippo burst out of the water. The guide and boatman kept a very wary eye on the movement of hippos as we are travelling along the river. You would be surprised how quickly a hippo can move through the water. Furthermore, do not be fooled by deep water they can run and bounce of the river bed surprising fast and continue the chase for longer than you might expect.

The biggest threat to a male hippo is another male hippo. This young male was not being allowed back into the water by the dominant bull who was not about to shy away from a confrontation. Most hippo fights take place in the water. Hippos live in pods or groups ranging from – on average – 30 individuals to bloats numbering up to 200 in the Luangwa river. Pods comprise females, their young and a single dominant bull. This bull will aggressively protect his females and territory against other male hippos. He won and maintains his dominant position through continue combat and confrontation.

The open jawed “yawning” display is usually a threatening posture. When an unwanted male enters the dominant bull hippo’s territory, the two size each other up. They will probably stand nose to nose and bellow their discontent. In an attempt to threaten each other they open their jaws as wide as possible, which can be as much as 150 degrees wide, to display their size and power as well as their sharp teeth. If that does not work it can end up in a pitch jaw battle. The hippos teeth tend to sharpen naturally through constant use throughout their life, and can grow to be up to three feet long, strong enough to cut deep into the opposition’s thick hide or the hull of an aluminium boat.

A typical family scene along the Chobe river in winter. The larger females and males are lying in the mud in the sun. The youngsters and younger females, probably mothers, got up when we passed by. The females were probably just protective of their youngsters. The hippos do not seem to be fussed about the crocodiles or all the birdlife around them. In this case there were hundreds of Egyptian geese which made a racket but this did not disturb the slumbering mud bathers.

“Only let the moving waters calm down, and the sun and moon will be reflected on the surface of your being.” ~Deepak Chopra

After the mating period, the female hippo has a long gestation period of around eight months and the birth usually takes place in the wettest season of the year. When it is almost time to give birth, the female hippo isolates herself from the pod until she has given birth to her calf (female hippos usually give birth to one calf but occasionally produce twins). The baby hippo is born underwater with its hind legs appearing first.

Hippos and elephant don’t usually tangle. This bull elephant had crossed the southern channel around Sedudu island to feed on the island. Hippos are highly territorial but although huge they are way smaller than a bull elephant. Elephants are not usually aggressive animals unless there are young to protect or water or grazing that they need to protect. Interestingly, this bull hippo did not give much ground to the confronting bull despite its major size and weight disadvantage. Thankfully the confrontation was over quickly with no damage done.

Nothing looks more relaxed and content than a hippo submerged in its salad. This hippo was neck deep in the river amongst water lilies and water grass. The late afternoon light was soft and warm and this hippo seemed to enjoy being adorned with water lily pads.

Hippos spend most of their time deep in water to cool and graze on the water grass in the river. They require about 45 kilograms of food a day to maintain that massive weight. Hippos are herbivores but their diet depends on what is available. Hippos generally do most of the grazing at night on land but along the Chobe the overgrazing by elephants has dictated that hippos have adapted to take advantage of the water lilies and water grass. Hippos are ruminants but have only three chambers to their stomach, not four as in other ruminants. Hippos do not chew the cud, a ball like mass of partly digested plant matter. The hippo also has a small and large intestine. The small intestine is where all the fats, proteins and fat are digested (or emulsified) by enzymes and absorbed. The large intestine has the function of absorbing the water that goes through it and excretes whatever bodily material is left over as defecation.

Like elephants, hippos are the gardeners of Africa’s river systems. Hippos keep channels open through the reeds and papyrus which improves the flow of the river. Hippos defecate a lot but this provides vital for food for the fish. In turn the fish feed the Catfish and Tigerfish and many waterbirds. The Catfish and Tigerfish in turn feed the Fish eagles and crocodiles. There is a trophic cascade.

“Few can sojourn long within the unspoilt wilderness of a game sanctuary, surrounded on all sides by its confiding animals, without absorbing its atmosphere; the Spirit of the Wild is quick to assert supremacy, and no man of any sensibility can resist her.” ~James Stevenson-Hamilton

Explore, seek to understand, marvel at its interconnectedness and let it be.

Have fun, Mike

3 thoughts on “Chobe’s river horses

  1. HI Mike, Yet another interesting story and superb photos. Many thanks. I think it’s time for you to start collating all your writings and photos into a book for posterity.

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