Landscaping is child's play for these guys. Put a group of hippos into a floodplain with lots of nice, soft soil and they'll start reconfiguring the turf like crazy. The massive creatures like to plow through the reed beds that ring bodies of water. This creates deep depressions in the underlying soil, which in turn become channels. Also, on hot days, hippos will sometimes relax in the cool comfort of freshwater pools.
However, these don't offer much in the way of food. So when hunger strikes, the hippos leave their little pools to feed elsewhere. All of this coming and going produces what Discover magazine once called "hippo highways."
Worn down into deep, plant-free ravines by wandering hippos, these footpaths can be as much as 16 feet (5 meters) wide and — just like gator holes — they're quick to fill up with water. What's more, hippo highways linking the pools to big rivers can also be established. If the area should flood, these connection points may become an outlet for surging water. They also enable swamplands to expand. And under the right circumstances, the trench-like trails will divert a great deal of sediment from rivers into lagoons or ponds.
So to make a long story short, just by going about their daily business, hippos can carve up and revamp Africa's waterways. Neat. But if hippopotamuses are true blue ecosystem engineers, then how do they affect other organisms?
Well, one 2015 analysis determined that hippo dung is an important source of nutrition for at least some of the fish and insects that share the animal's native range. Don't underestimate the power of poop.