Hippo Heaven What happens to a hippo when it sinks beneath the surface? Mzima was the place to find out. If there’s a 'must-see 'must-see for a freshwater naturalist in East Africa, then its Mzima Spring in Kenya's Tsavo West National Park. I first became aware of it as a teenager, when I was enthralled by documentary makers Alan and Joan Roots classic film Mzima: Portrait of a Spring with Spring with its extraordinarily clear underwater images of hippos. Back then, I would have assumed that there were other sites like it, scattered throughout throughout the continent.
I therefore counted myself fortunate when my partner Vicky and I eventually got the chance to visit Mzima itself with Alan Root. It was the dry season, and as Alan flew us over Tsavo I was looking forward to seeing Mzima for the first time. But when Alan dipped a wing, I was totally unprepared for what leapt out of the monochrome scorched plains.
I knew immediately that we had to make a film there and we believed that if we lived at Mzima for long enough then something incredible would reveal itself. Our goal was to film the behaviour of hippos under water to get some key sequences about which a story could be told. This meant diving with them so frequently that we gained their trust or filming them unobserved from an underwater hide.
So, after two weeks, we had only spent a total of thirty minutes underwater with no film and one attack to show for it. The chance of spending the thousands of hours underwater that we would normally do when making a film looked slim. Hippos are potentially more dangerous than crocodiles, but the more we explored the spring, the more numerous the crocodiles we found - and the bolder they became.
At the same time as trying to film underwater, we erected towers to give us an aerial view of the spring. From these, we could watch an entire group of hippos and look down through the water. What we saw was exciting. Female hippos were defending their young against crocodiles, but most extraordinary extraordinary of all, we could see the hippos opening their mouths and having their teeth cleaned by Labeo fish, which swarmed swarmed inside their gaping jaws.
The first time I tried it, this latest l atest hide was secreted in the shallows, in the shade of an overhanging fig tree. I was there waiting for the hippos to come close, when a troop of
baboons arrived to investigate and discovered that the tree was in fruit. As they fled, figs started to rain down from above.
At first it wasn't too bad but then the baboons realized that the best figs were in the branches directly above me. All this eating made them thirsty so they descended for a drink before carrying on with the feast. By the time Vicky came to relieve me, this had been going on for several hours, and the hippos had fled. There was only one thing for it; we would have to set about filming remotely. We ended up with a camera fixed to the bed of the spring and it took nine more months for the hippos to get used to that!
A I knew only too well what was coming next, but I couldn't escape. The golden rule about hide work is always to have someone else with you when you get in and out; any disturbance is then associated with that person and not the hide. But on this occasion, I was alone. B It rapidly became apparent to us that neither method was going to work. Whenever we tried to get into the water, the hippos would immediately either charge or flee. Meanwhile the local crocodiles became curious, and on the second or third dive on my way to the hide, I had been forced to fend one off by vigorously hitting it on the head with the camera. C We were .determined to film this underwater too, but progress was dismal. In an idea borrowed from Alan Root, our assistant constructed a new sort of hide, a type of 'reverse aquarium', comprising a large metal 'coffin', open on top, with a glass front through which we could film and stay dry. D This may be because hippos can't see particularly well underwater. They compensate for this by being sensitive to sound, including the high-pitched sound produced by the camera. Despite our efforts, we couldn't muffle it. E Nestled far beneath us was an oasis of liquid turquoise, set in a ring of yellow fever trees. We circled, and each time we passed over, we could see the forms of hippos asleep in the pool. Through the crystal clear water, we could make out the green shapes of crocodiles and pale blue fish. F With this in mind, we decided to build a tunnel of protective steel mesh to access the hide more safely. As a solution it seemed obvious, but the hippos found it obvious, too, and moved
away. We then left the hide alone for several months, hoping that the hippos would get used to it, but for some reason, they never did. G However, when I was filming hippos elsewhere in East Africa for a documentary twenty years later, I discovered that this was not the case. The hippos were swimming in muddy water holes and coffee-coloured rivers, so no matter how exciting the behaviour visible above the surface, every time a hippo’s nostrils pinched together, I knew my subject was about to disappear from view.
