It's not hard to tell when you are coming up to a hippo pool. It is the only thing in Africa that smelled. It seems that hippos declare their turf via projectile .. (well, you can imagine).
The hippos were an interesting group. Because their skin is so sensitive, they must wallow in the water all day long. If they are out of the pool during the day, they will end up with a horrible sunburn. Most of the time, we would only see the snout. The hippos can submerge for many minutes, so there were times when I felt that I was on a whale watch. They would surface only to breathe, then they would dive again.
The hippo is another animal which kills people. They leave the pool at night to forage, eating the grass around the pool. They can sometimes go for several miles on these foraging trips. You don't want to get between a hippo and his pool though. If you do, and he notices, you will be trampled and/or bitten to death.