You really have to know how unusual this is.
A lot of people will have no idea how unusual this is. If I'm in the bush in Africa and I hear a rustle I'm one of those curious people who wants to see what it is. With one exception that is. If' I'm near water and I hear a rustle in the bush I head the other way without looking. If it's a croc or a hippo I don't want to know about it unless a safe distance away. Both are vicious and will attack humans but the hippo is the far deadlier. First, they are huge but they are fast. People assume they can't run. Wrong! They will outrun you any day. And while both crocs and hippos can kill the hippo can do it a lot faster -- literally biting a human in half on the first try. Crocs don't fear anything except hippos. They will never mess with a hippo by choice.
I love to watch hippos, provided I'm far enough on shore or in a good size boat -- no canoes thank you. And that is why I always loved to take a cruise on St. Lucia Estuary. Every visit to the area include a cruise to go hippo watching. So seeing this hippo just follow this couple around like a puppy is quite amazing. I guess they don't have to worry much about crocs.
Now the funniest story related to these facts that I saw was about a large canoe that went down the Zambezi, just up from Victoria Falls. It was one of these double wide canoes that held quite a few people. One very stupid teen aged girl, actually from my part of the country, was riding on the right hand side and trailing her hand in the water. That is a very stupid thing to do. On her left was a very hefty woman. I mean very hefty.
The hand splashing in the water attracts a croc which comes up from underneath the canoe and clamps onto the girls hand pulling her into the river. But in the process of pulling the girl into the water it also managed to tip the canoe over as well. The very hefty lady landed on the croc. Now I can only surmise what the croc was thinking. But it seems likely that that this croc decided anything that large was a hippo. It let go of the girl and high tailed it out of there. Apparently this means Michael Moore can float down the Zambezi on his back with nary a worry except a lot of people wouldn't mention when the falls are coming up.