How to Take a Water Sample from a Hippo-Infested River

Yes, this is a question I have been asking myself since I first saw that Mara River documentary...how, exactly, does one take a water sample from a river full of crocodiles and hippos?

Here's my first view of the Mara River. You can see the hippos to my right, welcoming me.

This is a hippo skull, with a crocodile skull in the background, that rested at one of the main gates to the park. I have been warned about hippos since I first started thinking about Africa. They are considered one of the most dangerous wildlife over here because they are easily frightened, and woe to the person who comes between them and their escape into water. Also, you can see here how menacing their teeth are, even though they are really just big, lazy plant eaters. Crocodiles are another danger, as they can be practically invisible as they stay underwater for long periods of time.

So, I kept thinking to myself, exactly how am I supposed to get this hippo to agree to let me take a water sample here?


Well, as it turns out, hippos and crocs are like most other wildlife in the sense that they are generally much more afraid of people than we are of them, and they are more than willing to move out of your way. You can see above the hippo watching me test the water, and then deciding he didn't want too much to do with me.

Fortunately, we were accompanied on our sampling by the wildlife vet for the Kenya Wildlife Service, who taught us a few basic rules for safe river work:

1) Wait and watch for a while to see who already lays claim to the area. Neither hippos nor crocs can hold their breath forever. Generally, if you approach slowly and watch carefully, you can tell what animals are hanging around.

2) Respect their boundaries. If someone doesn't move out of the way, or there are more of them than you are of you, just go somewhere else.

3) Don't set yourself up for failure. Only get close to the water in areas where the bottom is fairly clear and shallow, and you can see anything that may be approaching. Keep your eyes open, and have others watch out for you, too. And don't linger too long right at the water's edge.

4) Be willing to accept no for an answer. No data is worth risking your life, so if an area is just too full of wildlife, or you don't think a situation is safe, just don't take a sample.

Can you find the hippos in this picture? They are the two black marks in the water just beyond the whitecaps.

Hippos generally like to hang out in groups, so it's usually pretty easy to spot them. Oh yeah, and they are 3.4-4.2 m long and weigh 1,000-2,000 kg, so they're pretty hard to miss!

Watching for tracks along the bank, like these hippo tracks above, also gives you clues about who lives in the area.

Hippos are actually very charming animals, and all of the ones we met this last week were pretty accomodating to our visit into their home. Any place you work, you have to remember to give appropriate boundaries to the critters who live there, and Africa is no different... the reminders are just bigger! That said, I think we will still work on rigging up a sample bottle on a long stick... just to be safe!