In case you've ever wondered, this creepy video gives a pretty good demonstration on just why you shouldn't swim with hippos.
Even though they may look like fat and slow creatures, hippopotamuses are the most dangerous mammals in Africa and kill several thousand people each year.
These guys obviously knew that (that's why they kept an elephant gun in the boat as a backup), which makes their decision to go scuba diving in hippo infested waters all the more perplexing.
Watch the video to see firsthand why you don't swim with hippos!
I'm not sure exactly what the heck these people were trying to accomplish (maybe the full-length episode provides some more background), but they were obviously taking a big risk in going scuba diving in hippo country.
They knew there were hippo in the area, they were following hippo tracks on the bottom of the river, and yet they were shocked to encounter a hippo under water.
It should go without saying, but I'll say it anyway: don't go swimming with hippos. Doing what they did is just asking for trouble and everyone was lucky that nothing serious ended up happening.