On land hippos can gallop at 20mph, that's very close to the fastest human sprinters.... just let that sink in for a moment. In the water, they actually don't swim but spend lots of time lounging in shallow water and walking along the bottom when they do move through deeper water. Their mouths can open 180° and they can easily chomp & tromp a human to death, it happens about 500 times a year - either you get too close in a small boat and they attack or at night you run into one on land and it feels threatened. Photographing from the water provided a unique perspective, nice and low, that I really like. It also let us drift quietly by, observing their behaviors, and most of the time they ignored us except num. 2 and num. 3 - that hippo decided we were a little too close. It was a mock charge meaning they never came all the way to the boat - just showing what was possible. We got the message and moved on.