GRAND DESIGNS

Thanks to their impressive stature, hippos just can’t help engineering the ecosystems around them

- MEGAN SHERSBY

THE HIPPO GLANCES AT US BRIEFLY, before continuing its lumber across the track. I can’t help thinking that it doesn’t seem to think much of us. Here in the South Luangwa National Park in eastern Zambia, dusk is fast approaching, the sun sinking inexorably towards the horizon. My guide, Patrick Njobvu, explains that it’s around this time each day that the hippos leave the pools and rivers in which they’ve spent the day, to graze on the land. They follow the same routes each night, creating paths across the land, which gradually become tracks and then, with repeated footfall and the downpours during rainy seasons, turn into channels and gullies. Patrick adds how, when they become deep enough, these gullies are used by leopards to stalk their prey.

Having been dismissed by the hippo, we carry on towards the viewpoint. It overlooks the river, which is now a brilliant orange in the setting sun, criss-crossed by the shadows of the trees on the opposite bank. A few hippos are still lounging in the waters.

All organisms on earth have an impact on their environment or other species in one way or another, I muse, but some modify their surroundings much more than others. Ecosystem engineers, as they are known, can be found all over the world. Think of ants or termites constructing mounds or the combined efforts of key coral-reef organisms. We humans do it to the extent that there is a proposed geological epoch to describe our impact on the planet – the Anthropocene.